ALBERT

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Kathryn L Page, Yash P. Dang, Ram C. Dalal, Steven Reeves, Greg Thomas, Weijin Wang, John P. Thompson〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉No-tillage (NT) has been widely adopted to assist in reducing soil erosion, lowering fuel costs, conserving soil water and promoting soil health. However, NT may also have a negative effect on yield depending on season and conditions due to inadequate weed/disease control, nutrient stratification and/or decreased soil temperatures. Therefore, to fully assess its impact, long-term studies are required to monitor changes over time. This study reports on the long-term effect of NT on crop yield and profitability (primarily for wheat, 〈em〉Triticum aestivum〈/em〉 L.) using results from an experiment that has been running for 50 years in a semiarid subtropical region of Australia. In this experiment, the effect of tillage (conventional till (CT) 〈em〉v〈/em〉 no-till (NT)), residue management (stubble burning (SB) 〈em〉v〈/em〉 stubble retention (SR)), and three rates of nitrogen (N) fertiliser (0, 30 and 90 kg N/ha) were measured in a balanced factorial experiment on a Vertisol (Ustic Pellusert). Over the period of the trial (1969–2018), NT with SR resulted in greater average soil water storage in the top 1.5 m of the profile than CT with SB (390 〈em〉v〈/em〉 346 mm). However, nitrate (NO〈sub〉3〈/sub〉-N) accumulation during the fallow period was generally lower with SR and this prevented wheat from fully capitalising of on the increased soil water storage. Consequently, while crop yield was greater under NT 〈em〉v〈/em〉 CT and more so under NT + SR 〈em〉v〈/em〉 CT + SR (particularly in years where in-crop rainfall was 〈˜300 mm), N fertiliser was required to maximise yields. Within the NT treatments, SR also resulted in greater yield in the presence of applied N. Prior to 1992, nematodes prevented wheat crops from capitalising on the increased soil water and reduced yields, however, the introduction of nematode-tolerant cultivars helped maximise crop production. In line with yield effects, gross margins were greater under NT than CT and for SR when N was applied. However, despite greater yield advantages for the 90 N treatments, gross margins were lower at 90 N compared to 30 N. Nitrogen use efficiency with 90 N was approximately half that with 30 N, likely due to greater losses of N at the higher rates of application. To maximise profitability techniques to reduce losses of N are thus desirable. Good disease control, or the use of tolerant/resistant cultivars, is also essential to allow the crop to capitalise on gains in soil water in NT systems.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Qi Chen, Pei-Qin Peng, Jian Long, Xin-Yang Li, Xianqing Ding, Hong-Bo Hou, Bo-Han Liao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉While the evaluation of cadmium (Cd) phytoavailability in rice (〈em〉Oryza sativa〈/em〉 L.)–soil systems has attracted considerable attention in recent years, the results vary based on the evaluation method used. The objective of this work was to use field capacity-derived soil solution extraction (SSE) to evaluate the Cd phytoavailability in two typical paddy soils (purple paddy soil and red paddy soil) during an entire rice growth season. Compared to three conventional extraction methods diethylenetriaminepentaacetic acid (DTPA) extraction, toxicity characteristic leaching procedure (TCLP), and HCl extraction], field capacity-derived SSE resulted in the strongest correlation between extracted Cd and the Cd contents in different rice tissues (root, gem, leaf, ear, husk, and brown rice). When the data for the two soil types were combined, SSE was the best predictor of total accumulated Cd in rice, with linear correlation coefficients of 0.836, 0.831, 0.919, and 0.909 for the tillering stage, heading stage, filling stage, and mature stage, respectively. In contrast, TCLP was only suitable for predicting total Cd accumulation in the heading and mature stages (linear correlation coefficients of 0.813 and 0.931, respectively), while DTPA was only effective in the heading stage (linear correlation coefficient of 0.8306). These results demonstrate the potential of field capacity-based SSE to predict Cd phytoavailability in soil–rice systems with different soil types.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0167198719300418-ga1.jpg" width="345" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Eunice Essel, Junhong Xie, Chaochao Deng, Zhengkai Peng, Jinbin Wang, Jicheng Shen, Jianhui Xie, Jeffrey A. Coulter, Lingling Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil microbial diversity is important in maintaining soil quality, sustainable agriculture, and ecosystem function. Soil management practices can influence the diversity and activity of soil microbes in agricultural fields. The objective of this study was to assess the effects of tillage and stubble management on the diversity of bacteria and fungi, chemical property and total carbon emission in the rhizosphere and bulk soils in wheat (〈em〉Triticum aestivum〈/em〉 L.) -pea (〈em〉Pisum arvense〈/em〉 L.) rotation at pre-harvest. Treatments included conventional tillage with stubble removed (T), no-tillage with stubble removed (NT), conventional tillage with stubble incorporated (TS), and no-tillage with stubble retained (NTS). Bacteria 16S rRNA (V3V4) and fungi ITS (ITS2) region genes were sequenced from bulk soil and rhizosphere soils. Abundance of the dominant bacterial (Actinobacteria, Proteobacteria, Chloroflexi, Acidobacteria, and Planctomycetes) and fungal (Ascomycota and Basidiomycota) phyla identified did not differ significantly (〈em〉P〈/em〉 〈 0.05) among treatments. 〈em〉Rhizobium〈/em〉 and rare fungi 〈em〉Kurtzmanomyces〈/em〉 occurred in the rhizosphere but were virtually absent in bulk soil. However, bacterial and fungal OTUs diversity indices were less in the rhizosphere compared to bulk soil. Soil from the NTS and NT had the greatest bacteria 16S rRNA and fungi ITS region number of OTUs; however, the microbial community did not differ among treatments. The abundance of class level bacteria and fungi were associated with soil pH, total organic carbon, total nitrogen, NH〈sub〉4〈/sub〉〈sup〉+〈/sup〉 -N, and NO〈sub〉3〈/sub〉〈sup〉¯〈/sup〉 -N contents. The results indicate that bulk soil had higher microbial library, which will be beneficial for establishment of the next season’s microbial community.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 195〈/p〉 〈p〉Author(s): Bin Zhang, Aizhen Liang, Zhanbo Wei, Xueli Ding〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soils simultaneously provide multiple ecosystem functions (i.e. multifunctionality) which are of critical importance in terms of climate regulation and fertility maintenance. Although the influence of tillage practices on many soil functions is well documented, its effect on the resistance and resilience of these functions to climate change from a ‘holistic ecosystem’ view remains poorly understood. In this study, we compared the resistance and resilience to dry-wet cycles, which is predicted to be more frequent and intensified in agricultural soils under climate change, of soil multifunctionality under no-tillage and ridge tillage. We found that no-tillage led to a higher resistance but a lower resilience of soil multifunctionality than ridge tillage in response to dry-wet disturbances. Variation partitioning analysis and mantel correlation between dissimilarity matrices showed that the resistance and resilience of soil multifunctionality was closely related to soil microbial diversity. Soil pH also contributed to the variation in stability of soil multifunctionality, but its explanatory power was much lower than microbial diversity. Our results suggest that tillage practices strongly affect the resistance and resilience of soil multifunctionality to dry-wet cycles, which might exert important consequences for ecosystem services that delivered by agricultural soils under climate change.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 195〈/p〉 〈p〉Author(s): Zihao Wu, Bozhi Wang, Junlong Huang, Zihao An, Ping Jiang, Yiyun Chen, Yanfang Liu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The spatial distribution of soil organic carbon density (SOCD) is crucial for understanding land use impact on carbon budget. The spatial estimation and accurate mapping of SOCD in plains remain challenging, partly due to the relatively invariant topography and the lack of consideration of landscape patterns. Here, we propose a novel landscape metric-based regression Kriging (LMRK) for the spatial estimation of SOCD in plains. Using 242 topsoil samples collected in the Jianghan Plain, China, we (i) investigate the scale-dependent relationship between SOCD and 24 landscape metrics and (ii) develop LMRK models with multi-scale buffers (100–1000 m) for SOCD estimation and compare their performance with ordinary Kriging (OK) and regression Kriging (RK) that integrates land use types. Results showed that LMRK outperformed other models. The relationships between SOCD and landscape metrics were found to be scale-dependent, and the buffer of 300 m exhibited the optimal scale in our case. The LMRK also revealed that a highly connected and water-sufficient landscape was conducive to the accumulation of soil organic carbon in farmlands. These results indicated that landscape metrics serve as good predictors, and the proposed LMRK method is effective for SOCD mapping in plains. Our findings highlight the scale-dependent relationship between landscape metrics and SOCD and provide a new perspective for soil mapping in plains.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 195〈/p〉 〈p〉Author(s): Haihou Wang, Mingxing Shen, Dafeng Hui, Ji Chen, Guofeng Sun, Xin Wang, Changying Lu, Jing Sheng, Liugen Chen, Yiqi Luo, Jianchu Zheng, Yuefang Zhang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Crop straw management plays important roles in sustainable agriculture and environmental protection. Straw incorporation has multiple influences on soil organic carbon (SOC) sequestration, greenhouse gas (GHG) emissions, and crop yields, but these influences have rarely been studied simultaneously in a single cropping system. This study was conducted to examine the influence of long-term straw incorporation on the SOC sequestration rate, methane (CH〈sub〉4〈/sub〉) and nitrous oxide (N〈sub〉2〈/sub〉O) emissions and crop yields in a Chinese rice (〈em〉Oryza sativa〈/em〉 L.) –wheat (〈em〉Triticum aestivum〈/em〉 L.) cropping system in Hydragric Anthrosols under a subtropical monsoon climate. Four straw incorporation treatments were applied: wheat straw incorporation only (WS), rice straw incorporation only (RS), both wheat and rice straw incorporation (WSRS), and no straw incorporation (as a control). The SOC sequestration rate was estimated from the changes in SOC stock in the topsoil (0–20 cm) from 2007 to 2016. The emissions of CH〈sub〉4〈/sub〉 and N〈sub〉2〈/sub〉O were measured every 7 d when possible using a static chamber method from the 2013 rice season to the 2016 wheat season. Our results showed that the straw incorporation treatments significantly influenced the seasonal CH〈sub〉4〈/sub〉 and N〈sub〉2〈/sub〉O emissions and rice yield but had no influence on wheat yield. Straw incorporation significantly increased the annual topsoil SOC sequestration rate by 0.24–0.43 t C ha〈sup〉−1〈/sup〉 yr〈sup〉−1〈/sup〉 and the annual CH〈sub〉4〈/sub〉 and N〈sub〉2〈/sub〉O emissions by 44–138 kg CH〈sub〉4〈/sub〉-C ha〈sup〉−1〈/sup〉 yr〈sup〉−1〈/sup〉 and 0.68–1.49 kg N〈sub〉2〈/sub〉O-N ha〈sup〉−1〈/sup〉 yr〈sup〉−1〈/sup〉, respectively. Relative to the RS treatment, the WS and WSRS treatments significantly increased annual CH〈sub〉4〈/sub〉 emissions by 38% and 61%, respectively. Relative to the RS treatment, the WSRS treatment significantly increased the annual N〈sub〉2〈/sub〉O emissions, by 35%. The average annual yields were significantly higher in the WSRS (16.8 t ha〈sup〉−1〈/sup〉 yr〈sup〉−1〈/sup〉) and RS (16.7 t ha〈sup〉−1〈/sup〉 yr〈sup〉−1〈/sup〉) treatments than in the WS (15.7 t ha〈sup〉−1〈/sup〉 yr〈sup〉−1〈/sup〉) and control (15.2 t ha〈sup〉−1〈/sup〉 yr〈sup〉−1〈/sup〉) treatments. Across the three rotation cycles, the annual net global warming potential and greenhouse gas intensity were similar between the control and RS treatments but were significantly lower in these treatments than in the WSRS and WS treatments. These findings suggest that the RS treatment can simultaneously increase crop yields and environmental sustainability in rice–wheat cropping systems.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 195〈/p〉 〈p〉Author(s): Milson Evaldo Serafim, Walmes Marques Zeviani, Fábio Benedito Ono, Leonarda Grillo Neves, Bruno Montoani Silva, Rattan Lal〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The increasing demand of society for agricultural products and environmental services, charges agriculture a convergence between productivity gains and soil quality. In view of this, the establishment of boundary values ​​for productivity and for soil quality in areas of high productivity and under conservation management systems were the target of this study. The objective of this study was to obtain reference values ​​for the chemical, physical and biological properties of areas under no-till (NT) management in the southern region of the state of Mato Grosso, Cerrado region, Brazil. A total of 65 commercial soybean crop areas were sampled at the 0.0–0.10, 0.10–0.20 and 0.20–0.40 m layers. The productivity of the stands selected for the study was higher than the state average (3.32 Mg ha〈sup〉−1〈/sup〉) and the national average (3.29 Mg ha〈sup〉−1〈/sup〉). In 26 of these areas, which represented environments of high soybean yield, the 3-year average productivity in 2015, 2016 and 2017 was above 4.2 Mg ha〈sup〉−1〈/sup〉. The use of a quantitative regression analysis was an effective way to obtain the limits of the interval that is considered adequate to assure high productivities for each property. Among the 75 replicated variables obtained from 29 soil properties of three layers, 18 were significant for soybean yield. The soil properties that were significant in at least one of the layers were acid phosphatase, calcium, magnesium, potassium, the S index, the soil water retention curve (SWRC) inflection point, field capacity, pH (H〈sub〉2〈/sub〉O), the available water capacity, bulk density, particle density and base saturation. The reference values ​​of the soil properties that are suitable for productivity are also indicators of good soil quality. These results indicate a convergence between a high productive potential and good soil quality, which was explained by the impact of the NT system on soil quality in the studied areas.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 195〈/p〉 〈p〉Author(s): Hanxi Wang, Jianling Xu, Xuejun Liu, Di Zhang, Longwei Li, Wei Li, Lianxi Sheng〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Long-term fertilization causes declines in soil quality and crop yield, hindering current agricultural development. This paper is about the effect of long-term fertilization (20 years) in Hunan’s Qiyang County. It was found that chemical nitrogen, phosphorus, and potassium (NPK) fertilizer lowered soil pH by an annual average of 0.07, while organic fertilizer increased soil pH by about 0.04. Furthermore, organic fertilizer and chemical fertilizer both increased total soil organic carbon (SOC). Long-term chemical NPK and organic fertilizer increased straw and grain yield of wheat and maize to a greater extent than did other fertilization methods. Thus, our results suggest that mixing organic fertilizer with chemical NPK fertilizer should prevent soil acidification and elevate crop yield.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 195〈/p〉 〈p〉Author(s): Iris Vogeler, Rogerio Cichota, Ingrid K. Thomsen, Sander Bruun, Lars Stoumann Jensen, Johannes W.M. Pullens〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Determining the nitrogen (N) release from catch crop residues is important for N management in arable farming systems. The use of catch crops and subsequent incorporation of its residues represents a nutrient provision for the following crop and has the potential of reducing N leaching. To investigate whether the Agricultural Production Simulator (APSIM) can be used to predict the N release from 〈em〉Brassica〈/em〉 catch crop residues with different carbon to nitrogen ratios (C:N) under different temperatures the model was set-up using three different approaches: (i) the generic approach, in which the residue is distributed to the various carbon pools with default APSIM parameters (Gen), (ii) the generic approach but with partitioning of the various pools based on the biochemical composition (Gen-BC), and (iii) the inclusion of an additional carbon pool in which mineralisation is based on first order decay and the C:N of the crop residue, termed simple mineralisation model (SMM). The SMM was parameterized based on results from various previous incubation studies. APSIM was then used to predict N release through mineralisation from these experiments. The simulations indicate that the generic approach in APSIM greatly underestimates the amount of N released from the cover crop residues, especially at low temperatures; the model efficiency (based on the Nash Sutcliffe efficiency score) was negative for the incubation study done at 2 °C. APSIM linked with the SMM shows a substantially higher prediction accuracy. The Gen-BC, which could only be done for one of the incubation experiments, had a higher prediction accuracy than the generic approach, but was not as good as the SMM. This indicates that, for accurate predictions of N mineralisation from 〈em〉Brassica〈/em〉 catch crop residues, the generic approach with default partitioning needs to be modified, either by assigning various carbon pools based on the biochemical composition or by including an additional carbon pool.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Yuan Li, Zhou Li, Song Cui, Sindhu Jagadamma, Qingping Zhang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Conservation tillage practices, here defined as no-tillage (NT) or reduced tillage (RT) with/without residue retention, have been widely used to alleviate the negative effects caused by intensive tillage practices. Implementing effective and sustainable agriculture requires a deeper understanding of the impacts of conservation tillage practices on soil physical properties. This study examined the effects of conservation tillage practices on soil physical properties, including soil bulk density, aggregate size and stability, hydraulic properties, and soil pH; based on data collected from 264 studies published worldwide since 1980. The results indicated that no-tillage (NT), NT with residue retention (NTS), and reduced tillage (RT) increased bulk density by 1.4, 2.6, and 2.1%, respectively, compared with conventional tillage (CT). Soil bulk density decreased by 2.9% in NTS compared with NT, and 3.9% in RT with residue retention (RTS) compared with RT. The effect size of bulk density significantly decreased with the increasing experimental duration under NT and NTS practices. Compared to CT, conservation tillage practices increased aggregate mean weight diameter (MWD), geometric mean weight diameter and water stable aggregate (WSA) regardless of the residue retention or minimum tillage systems. The largest effect size of MWD (51.9%) and WSA (54.9%) appeared under NTS as compared to the CT. The effect size of MWD and WSA increased under NT with the increasing experimental duration. NT increased saturated hydraulic conductivity by 24.6% compared to CT. All conservation tillage practices increased soil available water capacity (AWC) compared with CT and NTS with a 10.2% increase in AWC compared with NT. The effect size of AWC increased under RT and NT practices with the increasing experimental duration. Soil pH decreased by 1.7 and 1.0% under RTS compared with RT and CT, respectively; and NT led to a 2.8% reduction in soil pH compared with CT. The effect size of soil pH decreased under RT and NT treatments with the increasing experiment duration. Overall, conservation tillage practices positively affected many soil physical properties; and the extent of the effects varied with the duration of the experiment.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 195〈/p〉 〈p〉Author(s): Xiang Wang, Xin Dou, Xinle Zhang, Huanjun Liu, Houxuan Li, Xiangtian Meng〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil spectral allocation or classification is usually conducted on air-dried soils. However, the field soils are not all air-dried, and the change of soil moisture will affect soil reflectance. We introduce a soil allocation model that considers the effect of soil moisture for the purpose of eliminating the effect of soil moisture. The topsoil spectral curves of four typical soils from the Songnen Plain in Northeast China were re-sampled to 10-nm intervals and converted to first-derivative spectral curves and continuum removal curves. The spectral feature parameters were extracted from continuum removal curves in the visible-near infrared (VNIR) range (350–2500 nm), and the range of 430–2400 nm was used to build soil allocation models for reducing the effect of noise. Samples with different soil moisture were mixed into air-dried soils and we calculated the coefficient of variation (CV) of different inputs to assess the effect of soil moisture and to find allocation indices that were not affected by soil moisture. We used allocation indices of Zhang et al. (2018) because of the high accuracy of their DT (Decision Tree) model to allocate mixed-soil samples. We also used allocation indices that were not affected by soil moisture to allocate mixed-soil samples with decision tree (DT), multinomial logistic regression (MLR) and multi-layer perception neural network (MLPNN), and compared the results of the two methods. The results show the following: 1) As SFPs were built with shorter bands, SFP was less sensitive to soil moisture than PCR and PCFD and thus SFP is more suitable to build soil allocation models that consider the effect of soil moisture as input than PCR and PCFD. 2) Differences in soil moisture had little effect on absorption valley shoulders, symmetry and absorption positions, moderate effect on absorption area and depth, and a major effect on the slope of different bands. 3) The effect of soil moisture on continuum removal curves of different soil classes was variable. There was little effect on Arenosols, a moderate effect on Chernozems and Cambisols, and a large effect on Phaeozems. 4) The accuracy of the DT model using allocation indices that were not affected by soil moisture was 91.892% with a Kappa coefficient of 0.888. Our results suggest that it is feasible to build soil spectral allocation models that are not affected by soil moisture, and this improves the universality of soil spectral allocation, especially to field soils, which can be of considerable help in soil classification.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 195〈/p〉 〈p〉Author(s): Jian Luo, Zicheng Zheng, Tingxuan Li, Shuqin He, Yongdong Wang, Xizhou Zhang, Huagang Huang, Haiying Yu, Tao Liu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Rill erosion is one of the most serious problems in sloping farmland of purple soil. The formation and evolution of runoff and sediment associated with rill erosion are complex processes that are influenced by many factors. The aim of the present study was to investigate the temporal variation characteristics of runoff and sediment associated with rill erosion during the maize-growing season. Simulated rainfall experiments (1.0, 1.5 and 2.0 mm min〈sup〉−1〈/sup〉) were carried out in three experimental croplands on a typical slope gradient of 15°. Multi-scale temporal variation characteristics of runoff and sediment associated with rill erosion were identified by rescaled range (R/S) and wavelet analyses. The results showed that the Hurst index of the runoff ranged between 0.572 and 0.875 during the maize-growing season, while those of the sediment ranged between 0.575 and 0.855, indicating a long-range positive correlation. Therefore, the time series of runoff and sediment were persistent time series, and the future trends of runoff and sediment would be consistent with the present. The principal cycles of runoff and sediment presented an initial increasing and then a decreasing trend with maize growth, and the runoff and sediment yield varied periodically every 8–15 minutes. The changes in the primary cycles of runoff and sediment were basically consistent with the changes in vegetation coverage. The results provided a new insight for describing multi-time scale characteristics of runoff and sediment associated with rill erosion.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Ting Yang, Jirka Šimůnek, Minghao Mo, Blake Mccullough-Sanden, Hossein Shahrokhnia, Setrag Cherchian, Laosheng Wu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Salinity leaching is necessary to sustain agricultural production in irrigated croplands. Improving salinity leaching efficiency not only conserves water but also reduces groundwater contamination. Current leaching requirement (〈em〉LR〈/em〉) calculations are based on steady-state and one-dimensional (1D) approaches, and consequently, this 〈em〉LR〈/em〉 concept may not be applicable to drip irrigation (approximately 2D), which is becoming more common due to its higher water use efficiency. The aims of this study were to assess the salinity leaching fraction (〈em〉LF〈/em〉) in clay, loam, and sand soils under 1D (to mimic sprinkler irrigation) and 2D (to mimic drip irrigation) transient conditions with a numerical model (HYDRUS). Water applications used the actual irrigation scheme in an almond orchard located in central California without considering precipitation. Model simulations showed that soil salinity at the lower boundary (depth of 150 cm) reached steady-state in 10 years in HYDRUS-1D simulations. The leaching fractions calculated from the ratio of drainage-water depth to irrigation-water depth (〈em〉LF〈sub〉w〈/sub〉〈/em〉 = 〈em〉D〈sub〉dw〈/sub〉〈/em〉/〈em〉D〈sub〉iw〈/sub〉〈/em〉) and irrigation-water salinity to drainage-water salinity (〈em〉LF〈sub〉EC〈/sub〉 = EC〈sub〉iw〈/sub〉〈/em〉/〈em〉EC〈sub〉dw〈/sub〉〈/em〉) from HYDRUS-1D were similar among different textured soils. However, they were much higher under drip irrigation (2D) than under sprinkler irrigation (1D) when the same amount of water was applied, and 〈em〉LF〈sub〉EC〈/sub〉〈/em〉 values were much greater than the 〈em〉LF〈sub〉w〈/sub〉〈/em〉 values under 2D simulations. Salt balance (〈em〉SB〈/em〉) and leaching efficiency (〈em〉LE〈/em〉) indicated that sprinkler irrigation (1D) is more effective for salinity leaching than drip irrigation (2D). To improve salinity leaching efficiency, further evaluation of 〈em〉LRs〈/em〉 under drip irrigation is needed.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 195〈/p〉 〈p〉Author(s): Yuanhong Li, Zuoxi Zhao, Weicheng Xu, Zong Liu, Xiao Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉It is difficult to systematically classify and detect objects buried in tillage soil layers. There is no effective way to detect destructive objects in the soil. This paper presents a method and model of intelligently classifying hard objects of electromagnetic wave based on Finite Difference Time Domain (FDTD), especially the volume and shape of the object can destroy agricultural machinery in farming. It aims to improve the environmental detection technology of agricultural machinery and break through the limit of intelligent equipment. Firstly, in order to calculate the energy amplitude loss function of plane electromagnetic waves in farmland soil layer, the optimal Soil Layer and Electromagnetic Wave Model (SEM) is determined by using Blackman-Harris pulse as the excitation source; The absorption boundary condition of Uniaxial Perfectly Matched Layer (UPML) is also determined by test. Secondly, the forward modeling is performed by REFLEX and MATLAB software programming, the grid type forward modeling results, compared to electromagnetic wave results and real-time forward measured data by GPR in layered soil, there were verification and analysis. Measuring the relationship between different phase amplitude and electromagnetic wave energy between different materials, proved by experiment, the optimized 750 MHz excitation source function was verified experimentally and accuracy rate reached to 0.98 or 0.99 with FDTD model. The precision of actual depth and calculated depth of the object are not more than 0.02 m. The multi-channel amplitude analysis of five kinds of material of electromagnetic waves of metal, wood, PVC plastic, dry hard stone, and glass is obtained by SEM in different soil layers, and the classification accuracy is 100%, the optimal value of energy discrimination peak amplitudes of these five materials are 0.0183, 0.0028, 0.0043, 0.0069 and 0.0087. The research shows that the FDTD difference method is used to simulate the propagation mechanism of electromagnetic waves in the soil. The SEM of GPR forward modeling can be established efficiently and accurately. The results can provide theoretical and technical support for the GPR soil matter or objects classification system and agricultural machine farming modules to detect objects buried in the soil layer.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): G.A. Miller, R.M. Rees, B.S. Griffiths, B.C. Ball, J.M. Cloy〈/p〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 195〈/p〉 〈p〉Author(s): Lidong Ren, Tommy D’Hose, Greet Ruysschaert, Jan De Pue, Redouane Meftah, Veerle Cnudde, Wim M. Cornelis〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Slurry spreaders are among the heaviest machines used for farming operations. The effects of soil wetness and tyre pressure on physical soil properties were evaluated by using a ˜5 Mg wheel load slurry spreader mounted on a tractor. The impacts were also compared with Terranimo® model predictions and X-ray micro-computed tomography (X-ray micro-CT) parameters. In the consecutive maize growing season, soil physical properties, total mineral nitrogen content and maize above biomass were evaluated additionally between in and out track positions. Immediately after traffic, penetration resistance (PR) was significantly higher (〈em〉P〈/em〉 〈 0.05) under moist conditions and at in-track positions compared with dry conditions and out-track positions for the top 10 cm. Tyre pressure did not affect PR at in- or out-track position. At 10 cm depth, bulk density and macro-porosity (d〉 30 μm) of soil trafficked under moist conditions was different (〈em〉P〈/em〉 ≤ 0.10) from those under dry conditions. Macro-porosity showed a clear response (〈em〉P〈/em〉 〈 0.10) to tyre pressure and all the trafficked treatments. Deeper in the profile, there were no significant differences in these soil physical quality indicators. X-ray micro-CT results agreed well with the soil physical quality indicators, and detected slight changes in degree of compaction more precisely. Terranimo® well predicted the contact area and mean ground pressure (RMSE=0.06 m〈sup〉2〈/sup〉). It indicated considerable compaction risk from the tractor’s rear wheels, which seemed to contradict with the relatively minor changes in soil physical properties observed. In the maize growing season, soil physical properties and nitrogen content showed no significant differences (P 〉 0.05) between in- and out-track positions while above ground dry biomass of maize reduced with ˜7% at in-track positions.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 7 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research〈/p〉 〈p〉Author(s): Marc Corbeels, Rémi Cardinael, David Powlson, Regis Chikowo, Bruno Gerard〈/p〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 195〈/p〉 〈p〉Author(s): Peter L. O’Brien, Aaron L.M. Daigh〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Tillage is commonly implemented worldwide to improve crop productivity by optimizing soil temperature and moisture, reducing penetration resistance of the seedbed, and suppressing weeds. However, these benefits are accompanied by drawbacks, including increased erosion and loss of soil organic matter. Research continues on how to maximize benefits and minimize drawbacks of tillage in a range of agricultural systems. The surface energy balance (SEB) may be a promising avenue for future tillage research because it describes the partitioning of energy into compartments crucial to crop productivity, especially heating the soil and evaporating water. Despite this relevance, very little research addresses the effects of tillage on the SEB, and the existing literature does not adequately describe the relationship between these two topics. The aims of this review are to identify research that has been completed on the subject, synthesize current knowledge, and propose topics for continuing research. This review suggests that alterations to soil surface cover, surface roughness, and near-surface porosity caused by tillage are reflected in changes in the SEB, with the greatest effects evident during wetting-drying cycles. The total available energy is increased following tillage, but the magnitude of change and partitioning of that energy is not understood, which directly relates to the energy available for heating the soil and evaporating water. Future research should focus on quantifying the magnitude of effects of tillage on the SEB, how those effects change over time, and identifying any other indirect effects that may inform better management decisions.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 195〈/p〉 〈p〉Author(s): Pu Shi, Rainer Schulin〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Dissolved organic carbon (DOC) constitutes the largest carbon pool in surface waters, with soil being its main source via surface and subsurface runoff. Amendment with organic residues can reduce soil erosion and surface runoff, but little is known how this affects the amount and composition of DOC losses via surface runoff and the associated transfer of nutrients and pollutants. In this study, artificial rainfall experiments were conducted on three pairs of soil runoff plots with contrasting organic matter management. A mixture of grass and wheat straw residues was incorporated into the topsoil of one plot in each pair (OI treatment) but not into the other (control). Artificial rainfall was applied onto both treatments at an intensity of 49.1 mm h〈sup〉−1〈/sup〉, and surface runoff samples were collected at designated time steps for analysis of DOC, total dissolved phosphorus (TDP), copper (TDCu) and zinc (TDZn) concentrations, as well as for characterization of DOC by UV–vis absorbance (SUVA〈sub〉254〈/sub〉 and E2:E3) and fluorescence spectroscopy (FI) indexes. The organic amendment reduced the loss rates of DOC, TDP, TDCu and TDZn by reducing surface runoff, although increasing the concentrations of DOC, TDP and TDCu. Regardless of the treatment, DOC, TDP and TDCu concentrations were always maximal at the onset of runoff and then continuously decreased after the initial flush. The observed relationships of TDP and TDCu concentrations with DOC indicate that the export of “dissolved” P and Cu primarily occurred in DOC-bound form, while the concentration of TDZn was not correlated with that of DOC. Surface runoff from the amended soils generally contained more hydrophilic and low molecular weight DOC (as indicated by low SUVA〈sub〉254〈/sub〉 and high E2:E3 and FI values), particularly at high DOC concentrations. The ratio between TDCu and DOC concentration showed a positive relationship to DOC aromaticity (as indicated by SUVA〈sub〉254〈/sub〉 values) in the OI treatment. The results indicate that organic amendment can reduce total rates of dissolved element losses with surface runoff, but attention should also be paid to the composition of lost DOC and the concentrations of DOC-associated solutes.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 195〈/p〉 〈p〉Author(s): Songsong Gu, Qiulong Hu, Yuqi Cheng, Lianyang Bai, Zhonghua Liu, Wenjun Xiao, Zhihua Gong, Yueni Wu, Kai Feng, Ye Deng, Lin Tan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil microbiomes contribute to plant growth, health and agricultural production. However, the influence of long-term application of different fertilizers on soil microbial diversity and community structure of tea (〈em〉Camellia sinensis〈/em〉) plantations remains unclear. Here it was hypothesized that organic fertilizer treatment (OF) would significantly improve the microbial diversity and alter the microbial community structure, leading to the support of more soil ecosystem functions in tea plantation. To test this, we investigated microbial communities of tea plantation soils under different long-term fertilization treatments using both high-throughput 16S rRNA gene Illumina sequencing and molecular ecological network analysis. Soil samples (Red soils, classified as Haplic Acrisol) were collected from 5 large experimental tea plantations under different long-term fertilization treatments (organic fertilizer (OF), chemical fertilizer (CF) and non-fertilizer (NF)) in central south of China in August 2017. Soils under OF treatment had higher microbial diversity compared with soils under other treatment regimes. Unweighted principal coordinate analysis (PCoA) results revealed a clear separation among the groups of tea plantation soils under the three treatment regimes. Relationship analysis between soil properties and microbial communities showed that pH and nitrate nitrogen (NO〈sub〉3〈/sub〉-N) concentration were key physicochemical factors that significantly influenced microbial diversity and community structure. Furthermore, network analysis indicated that the network of OF treatment soils contained more functionally interrelated microbial modules than soils with CF treatment and that the topological roles of characteristic microorganisms and key microbial organisms were significantly different between CF and OF treatments. Relative to CF treatment, the relative abundances of organisms belonging to chemoheterotrophy, fermentation, nitrogen fixation, and aerobic nitrite oxidation functional groups in tea plantation soils under OF treatment were significantly increased by 28.74%, 110.10%, 41.16% and 556.64%, respectively (〈em〉p〈/em〉 〈  0.05). It was concluded that OF treatment could improve microbial diversity, alter microbial network structure and enhance potential ecosystem function in tea plantation soils.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Giorgio Baiamonte, Agata Novara, Luciano Gristina, Francesco D’Asaro〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the field of conservative agriculture, no-till (NT) management has been receiving increasing interest, with 45 million ha of land under no-till management in 1999 to 155 million ha in 2014. Up until now, no-till has only been observed to perform better under rainfed conditions, especially in dry climates mainly because the reduced tillage system retains more soil moisture. However, the adoption of alternative agricultural practices (NT) can be improved only if uncertain and consequent assumption of risk is well known and accepted. For these reasons, the aim of this research is (i) to define durum wheat suitability under NT soil management in terms of yield success probability and (ii) to determine the suitable area for NT wheat cultivation within three climatic periods (the past, present, and future). The probability distribution of the aridity index (〈em〉AI〈/em〉) was used to derive the non-exceedance conditional probability of NT yield success in comparison to conventional tillage (CT) on arable land in the Sicilian Region (southern Italy). The probability of NT management resulting in a higher yield than CT management for each specific environment was predicted. The latter made it possible to determine the probability of a higher yield under NT practice in comparison to CT, considering both the environment (aridity index) and different management practices (cropping system and residue management). An analysis of the relationship between the crop yield and the 〈em〉AI〈/em〉 showed that the probability of NT success in durum wheat yield is affected by cropping systems and residue management and that Sicilian climatic trends will determine an increase in the areas suitable for NT durum wheat management. The uncertainty quantification or the success yield probability of NT could be used to target incentives for NT durum wheat cultivation in areas (within a region) where the mean yield and non-exceedance probability are low.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Loraine ten Damme, Matthias Stettler, François Pinet, Patrick Vervaet, Thomas Keller, Lars Juhl Munkholm, Mathieu Lamandé〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The use of today’s heavy machinery in agriculture poses a great risk to soil in the form of compaction. Subsoil compaction has been found to persist for decades, thus reducing the risk is extremely important. The stress distribution in the contact area between the tyre and the soil is of primary importance for the propagation of stress in the soil. The characteristics of the tyre therefore affect soil stress. The objective of this study was to compare effects of five generations of tyres (introduced from before the 1970s to 2018) on soil stress and soil structure, including two standard narrow tyres and three larger low-aspect-ratio tyres. Wheel loads of 2900 and 4300 Mg were chosen for the front and rear axles respectively, and the load-rated inflation pressure ranged from 240 to 60 kPa. The contact stress distribution was estimated using the FRIDA model and was used as input for calculation of the vertical stress through the soil profile. Mean normal stress and physical properties were quantified in a field experiment on a clay soil in Clermont-Ferrand, France. The results show that for a given wheel load, the tyre-evolution reduced soil stress when the development included an increase in the tyre-soil contact area and an associated decrease in the tyre inflation pressure. FRIDA model calculations indicated a reduction in soil stress for newer tyres due to a more even contact stress distribution, and were confirmed by the mean normal stress measurements. Although the difference in soil stress between the various tyres decreased with depth, a significant reduction was measured even at 0.6 m depth beneath the centreline of both front and rear tyres. We found only a very limited effect of the traffic on the dry bulk density and air permeability at 0.3 m depth below the centre of the tyres.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 195〈/p〉 〈p〉Author(s): Meiyan Wang, Shengxiang Xu, Chao Kong, Yongcun Zhao, Xuezheng Shi, Naijia Guo〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The conversion of cereal to vegetable represents a significant shift in land use in China, and it causes significant changes in soil properties. Most studies have only focused on chemical or biological properties; few have investigated soil structure. Soil structure, especially macropore space, is very important for plant growth because of its relation to important soil functions and processes, such as gas diffusion and water permeability. The objective of this study was to assess the effect of land use conversion from rice to vegetable on soil macropores (〉50 μm) measured by computed tomography (CT) and to examine the relationships between CT-measured pore characteristics and soil chemical properties. By using space instead of time, we sampled three land uses – rice/wheat rotation (RWR), open-field vegetable (OFV) and plastic-greenhouse vegetable (PGV) – in a tilled and plow pan layer in a suburban area of Nanjing, China, and analyzed the basic physicochemical properties and CT-measured macropore characteristics. The results showed that the tilled layer soil had a significant response to the land use change. The macroporosity decreased from 11.5% under RWR to 8.0% under OFV and 5.8% under PGV, and the decreased portion consisted mainly of elongated large macropores (〉1000 μm). In addition, the macropore morphology of vegetable fields also showed degradation, with a higher degree of anisotropy (DA) and lower fractal dimension (FD) and connectivity compared to those under RWR, but PGV experienced a higher degree of degradation than did OFV. This study also showed that soil structure degradation was significantly correlated with decreasing soil organic matter (SOM). Increasing the amount of organic fertilizer applied might improve the SOM content and therefore improve the soil structure. Based on the linear regression equation, adding 1 g of SOM per kilogram of soil can improve the macroporosity by 0.54 m〈sup〉3〈/sup〉 m〈sup〉−3〈/sup〉.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 195〈/p〉 〈p〉Author(s): Xiangwei Gong, Chunjuan Liu, Jing Li, Yan Luo, Qinghua Yang, Weili Zhang, Pu Yang, Baili Feng〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Cereal-legume intercropping has been widely used to increase productivity and achieve sustainable development in modern agricultural systems. However, there has been few studies of intercropping in minor grain crops, and we therefore designed an experiment to monitor rhizosphere soil properties, enzyme activities, and the microbial community diversity of proso millet (〈em〉Panicum miliaceum〈/em〉 L.) under proso millet /mung bean intercropping systems on the Loess Plateau of China, and a sole planting was used as a control. Illumina sequencing of the 16S rRNA gene and ITS gene was used to analyze soil microbial (bacterial and fungal) diversity and composition. The results showed that the rhizosphere soil nutrient contents and enzyme activities were higher under intercropping patterns with significant correlations being observed. The physical properties were also changed, including the soil water content, bulk density, and soil temperature. The effect of intercropping patterns on bacterial diversity was larger than that on fungal diversity, especially alpha diversity, although both groups were markedly affected by intercropping patterns. 〈em〉Actinobacteria〈/em〉 was the most abundant bacterial phylum, which was decreased by 32.37% under intercropping. Other phylum species, including 〈em〉Proteobacteria〈/em〉, 〈em〉Chloroflexi〈/em〉, 〈em〉Gemmatimonadetes〈/em〉, 〈em〉Acidobacteria〈/em〉, 〈em〉Nitrospirae〈/em〉, and 〈em〉Firmicutes〈/em〉 were also markedly affected by intercropping patterns. For the dominant fungal phyla, 〈em〉Ascomycota〈/em〉, 〈em〉Mortierellomycota〈/em〉, and 〈em〉Basidiomycota〈/em〉 did not respond substantially to intercropping patterns. Binding spatial ordination analysis demonstrated that soil temperature and bulk density for bacteria and total nitrogen and nitrate contents for fungi contribute more to the microbial community than the other investigated soil parameters, whereas the soil enzyme activities played the same roles in bacteria and fungi. Overall, these results suggest that intercropping alters soil microbial community composition, and the soil bacteria reflect changes in soil properties and enzyme activities better than fungi. Meanwhile, these findings also provide insights into the mechanisms underlying the maintenance of biodiversity in the agro-ecosystems functioning.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Huifeng Wang, Lipeng Yao, Biao Huang, Wenyou Hu, Mingkai Qu, Yongcun Zhao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil fertility should be explored from a productivity perspective because the most important function of the soil is to ensure crop yield. This study presents an integrated and scientific approach to exploring soil fertility based on rice (〈em〉Oryza sativa〈/em〉 L.) yields, using Jinxian County as an example. The main soil types are Haplic Acrisols and Hydragric Anthrosols. Five soil fertility indicators (〈em〉p〈/em〉-Value 〈 0.05) were selected according to the generalized additive model (GAM) hypothesis test between the rice yield and each indicator. Furthermore, these indicators were used to assess the quality of soil fertility via Takagli and Sugeno (T-S) fuzzy neural networks models. Finally, the geodetector model was used to explore the restricting indicators of soil quality that can influence rice yields. The results indicate that continuous fertilization for decades has improved the surface soil organic matter (SOM) concentrations in the study area. However, the surface total potassium (K〈sub〉T〈/sub〉) was still low at a mean value of 13.95 ± 4.74 mg/kg. The determination power (DP) of exchangeable magnesium (0–20 cm) and K〈sub〉T〈/sub〉 (20–40 cm) of 0.067 and 0.061, respectively, revealed that the proper use of potassium and magnesium fertilizers can increase rice yields. This integrated soil fertility exploration could scientifically assess the soil fertility and identify mainly restricting indicators of soil fertility in the study area. Moreover, these effective models with minor adjustments could be applied to assess soil fertility in other typical areas.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Murali K. Darapuneni, Leonard M. Lauriault, Syam K. Dodla, Omololu J. Idowu, Kulbhushan Grover, Gasper Martinez, Koffi Djaman, Sangamesh V. Angadi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Utilizing manure as a cost-effective plant nutrient source under dryland farming is often undermined by transportation and application costs of large quantities of manure. Reducing application quantities by applying manure only to the strip-till (ST) zone also may help reduce possible eutrophication and nitrate contamination of ground and surface water. A 3-yr study conducted at New Mexico State University’s Agricultural Science Center at Tucumcari, NM USA, compared the effectiveness of a one-time application of manure in the ST zone using dryland sorghum (〈em〉Sorghum bicolor〈/em〉 L.) as the test crop in four randomized complete blocks each year. Treatments were an ST control and manure rates [11 (Low (L)) and 22 (High (H)) Mg ha〈sup〉−1〈/sup〉] in combination with application techniques [surface (S) and 15 cm incorporation by ST (I)]. Significant treatment X year interactions existed (〈em〉P ≤ 0.05〈/em〉) for sorghum biomass yield, tissue N and P, water-use efficiency (WUE) and the majority of residual soil characteristics with the H + I treatment consistently having greater results compared to the other treatments every year. The WUE for control, L + S, L + I, H + S, and H + I were 8.9, 9.9, 10.3, 11.7, and 13.9 kg ha〈sup〉−1〈/sup〉 mm〈sup〉−1〈/sup〉, respectively, three years after the single manure application (〈em〉P 〈 0.01〈/em〉, SEM = 0.674). Despite having the higher biomass yield and tissue N and P concentrations, H + I continued to show high residual soil N and P, even three years after the single manure application. Consequently, significant agricultural benefits from a one-time application of manure continued to be evident beyond a three-year period. Due to predominant semi-arid dryland conditions, the N and P runoff losses were not evident in this study.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Khurram Shahzad, Andy I. Bary, Douglas P. Collins, Linda Chalker-Scott, Muhammad Abid, Henry Y. Sintim, Markus Flury〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Mulching is a common soil management technique used in agricultural, nursery, and landscape settings. Despite multiple benefits, such as reducing weeds and evaporation, some mulches can also hinder gas exchange across the soil-atmosphere interface, and thus may have negative impacts on plant growth. The objective of this study was to determine to what degree commonly used landscape mulches will affect carbon dioxide and oxygen concentrations in the root zone and gas exchange across the soil-atmosphere interface in a controlled greenhouse environment. We used mesocosms filled with a soil-compost mix and covered the surface with different mulches. The experimental treatments included no mulch (control), arborist wood chip mulch, cardboard mulch, landscape fabric mulch, and polyethylene film mulch. The flux of CO〈sub〉2〈/sub〉 across the soil-atmosphere boundary was measured with the dynamic closed chamber method. Concentrations of CO〈sub〉2〈/sub〉 and O〈sub〉2〈/sub〉 were measured in the mesocosms at two depths (6.5 and 13.5 cm) for a total of 16 days after covering the mesocosms with the mulches. Diffusion coefficients of CO〈sub〉2〈/sub〉 through mulch materials were of the order of 〉10〈sup〉−3〈/sup〉, 10〈sup〉−4〈/sup〉, 10〈sup〉−5〈/sup〉, and 10〈sup〉−6〈/sup〉 cm〈sup〉2〈/sup〉 s〈sup〉−1〈/sup〉 for wood chips, cardboard, landscape fabric, and polyethylene film, respectively. Despite the different diffusion coefficients of the different mulches, CO〈sub〉2〈/sub〉 and O〈sub〉2〈/sub〉 concentrations in the soil under the various mulches were not significantly different as compared to the control, except for the polyethylene treatment. The orders of magnitude differences in diffusion coefficients among the mulch materials, however, could negatively impact a diverse soil environment such as those found in biologically rich landscapes with higher oxygen demands. Among the mulches tested, wood chips are a preferred method of mulching in terms of providing best gas permeability, particularly in landscape conditions.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Annett Latsch, Thomas Anken〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Traffic induced soil compaction, as well as the associated negative effects on soil structure and soil functions can be reduced by the use of permanent traffic lanes for all field vehicles – known as Controlled Traffic Farming (CTF). Adapted to the small-scale agriculture in Switzerland, a simplified version may be applicable. In the current study, we evaluated the implementation of a “CTF-light” system in the Swiss Central Plateau specifically for heavy machines used for crop protection, fertilisation and harvesting. During a three-year trial (2015–2017), we investigated the practicality of this “CTF-light” system by using standard machinery on 17 study sites. The effects of permanent lanes on soil penetration resistance, water infiltration rate, bulk density, macropore volume and yields were evaluated. Harmonising machine working widths was challenging and required intense planning, however, we were able to realise “CTF-light” on all sites. After three years of controlled trafficking, we observed developing differentiation of soil properties. In untrafficked areas, there was a tendency of decreased penetration resistance and bulk density as well as an increased infiltration rate and macropore volume. This significantly increased maize yield, which is very sensitive to soil compaction. For other field crops, no consistent yield differences have yet been determined. The technical and organisational effort to realise permanent traffic lanes for heavy standard machines is not to be underestimated.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 195〈/p〉 〈p〉Author(s): Junhua Zhang, Zhigang Bai, Jie Huang, Sajid Hussain, Futao Zhao, Chunquan Zhu, Lianfeng Zhu, Xiaochuang Cao, Qianyu Jin〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Biochar is used mainly to alleviate salt stress in arid and semiarid soils, or to regulate acidification stress in paddy soils. However, the effects of biochar on paddy soil environments under salt stress and the biochemical characteristics of rice seedlings differing in salt tolerance are unclear. This study explored whether and how biochar is involved in alleviating salt stress in paddy soil and regulating the biochemical characteristics of rice seedlings. The trial was conducted under pot culture conditions, and NaCl was used as the salt stress agent in paddy soil. Two rice varieties were used in this trial: Jinyuan 85 (a salt-tolerant rice variety) and Nipponbare (a salt-sensitive rice variety). The salt stress included three treatments: 0 g NaCl kg〈sup〉−1〈/sup〉 dry soil (control, S〈sub〉0〈/sub〉), 1 g NaCl kg〈sup〉−1〈/sup〉 dry soil (S〈sub〉1〈/sub〉), and 3 g NaCl kg〈sup〉−1〈/sup〉 dry soil (S〈sub〉3〈/sub〉). Biochar produced by rice straw involved three treatments: no biochar (control, C〈sub〉0〈/sub〉), biochar produced at 300℃ applied into soil (C〈sub〉300〈/sub〉), and biochar produced at 600℃ applied into soil (C〈sub〉600〈/sub〉). The results suggested that the adsorption ability of the biochar produced at 600℃ was significantly higher than that of the biochar produced at 300℃. Bulk density, electrical conductivity, exchangeable Na〈sup〉+〈/sup〉 and exchangeable Cl- in the soil under salt stress were greatly decreased by the application of biochar, and the soil environment of C〈sub〉600〈/sub〉 was more favorable for rice seedlings. The salt accumulations in the rice seedling, and the microstructure of the root and leaf of the rice seedlings under salt stress were significantly and positively affected by the biochar, and the biochemical characteristics of the rice seedlings also greatly improved in response to biochar application. The responses of Nipponbare to salt stress were more severe than those of Jinyuan 85, while the regulatory effects of biochar were more favorable for Jinyuan 85 than for Nipponbare. In conclusion, biochar, especially that produced at 600℃ in this trial played a positive role in alleviating the inhibitory effects of salt stress on rice seedlings, and might be useful as an amendment in saline soils to improve rice plant growth.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0167198719304805-ga1.jpg" width="356" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Gary Feng, Ardeshir Adeli, John Read, Jack McCarty, Johnie Jenkins〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Keeping soil healthy as a medium that can supply adequate nutrients for plant growth is essential for sustainable agriculture. Large amounts of poultry litter are generated on commercial poultry farms in the southeastern United States. While applying poultry litter generally enhances soil nutrients and crop productivity, few studies have investigated changes in soil physical and hydraulic properties. As part of a larger study on cotton (〈em〉Gossypium hirsutum〈/em〉 L.) response to pelletized poultry litter (PPL), this study investigated soil physical and hydraulic properties in a Marietta fine sandy loam soil at two times, in the fall of 2014 and spring of 2015, after repeatedly applying 6.7 Mg ha〈sup〉−1〈/sup〉 PPL in a precision sub-surface band, 134 kg ha〈sup〉−1〈/sup〉 N (as ammonium nitrate) in subsurface bands and no fertilizer (control) for four years (2010–2013). Soil measurements were made at 0–15 cm depth in three plots of each treatment randomized as a complete block design. As compared to unfertilized plots measured in fall 2014, annual applications of PPL increased soil aggregate stability, plant available water, field capacity, saturated hydraulic conductivity, and infiltration by 10, 52, 26, 80, and 54%, respectively. These same soil properties measured in spring 2015 were greater in PPL than control plots by approximately 16, 28, 18, 90, and 100%, respectively. In fall 2014, soil bulk density and penetration resistance were approximately 6 and 19% lower, respectively, in PPL than unfertilized plots. In fall 2014 and as compared to commercial N fertilizer, annual PPL applications increased soil aggregate stability, plant available water content, field capacity, saturated hydraulic conductivity, and infiltration by 6%, 18%, 11%, 38% and 44%, respectively. These results are useful for development of management practices that improve soil health and function.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Sambo Pheap, Clara Lefèvre, Alexis Thoumazeau, Vira Leng, Stéphane Boulakia, Ra Koy, Lyda Hok, Pascal Lienhard, Alain Brauman, Florent Tivet〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As a response to the worldwide challenge raised by soil degradation, Conservation Agriculture (CA) was proposed to help restoring the three main soil functions, i.e. carbon transformation, nutrient cycling and structure maintenance. However, there is still a lack of integrative studies that assess the overall impact of CA on soil health. To fill the gap, Biofunctool®, a set of in-field indicators, was developed to monitor changes in soil biological functioning. In this study, Biofunctool® was used to assess the impact of a conventional tillage (CT) and three CA annual-based cropping systems on soil health on a Cambodian Oxisol. Eight indicators related to the three soil functions were monitored and integrated into a Soil Quality index (SQI), i.e. the Biofunctool® Index. Overall, we found that soil health was twice higher under the CA treatments than under CT treatment. Although it was similar in the three CA treatments, the contribution of each soil function to the soil health diverged. An analysis of soil carbon dynamics also showed that CA support short-term soil organic carbon stabilization compared to CT. This study demonstrates that Biofunctool® is a robust, relevant, time-and cost-effective in-field assessment tool that can be used in multiple ways including cropping system management, capacity building of local stakeholders, and policy dialogue.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Mei Lu, Shaojun Wang, Zhe Zhang, Minkun Chen, Shaohui Li, Run Cao, Qianbin Cao, Qianqian Zuo, Ping Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Ants act as ecosystem engineers in regulating soil heterogeneities. Little is known about the degree and direction of these modifications on soils across a restoration chronosequence of tropical forests. Our objectives aimed to explore the effect of belowground-nesting ants on soil characteristics across four forest restoration stages (i.e., 12-, 28-, 42- and 53-yr olds) on slash-burn lands in the tropical Xishuangbanna, southwestern China. We confirmed the hypotheses about a positive effect of ant colonization on soil physical characteristics, and on the enrichment of microbial carbon and mineral nutrients in nest soils across the four restoration stages. Ant nests had the highest enrichment of soil organic matter (103%), readily oxidizable carbon (78%), total nitrogen (114%), available nitrogen (126%), NH〈sub〉4〈/sub〉〈sup〉+〈/sup〉 (133%) and NO〈sub〉3〈/sub〉– (140%) at the 12-yr old stage compared with the surrounding soils. In contrast, the highest enrichment of microbial carbon (110%) in nest soils was showed at the 53-yr old stage. The enrichment of microbial carbon in nest soils increased with restoration age, but that of soil mineral nutrients would not follow the forest restorations. A higher enrichment of mineral nutrients in nest soils at the early restoration stage can improve soil fertility, which might promote the spontaneous forest restorations. A higher abundance and area of ant nests at the older restoration stage may create a higher bare space for plant development. Therefore, our results suggest that ant colonization can regulate forest restorations, possibly through creating and maintaining higher soil nutrient heterogeneity at earlier stage, and greatly stirring microbial growth and opening up space for plant development at older stage on slash-burn tropical lands.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0167198718312492-ga1.jpg" width="210" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Ryan R. Busby, H. Allen Torbert, Stephen A. Prior〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The United States Army produces a significant amount of classified paper waste that is pulverized to a fine consistency unsuitable for recycling. However, cheap, high quality organic materials such as classified paper waste are useful as soil amendments. The objective of this research was to evaluate the utilization of pulverized classified paper waste as a soil amendment to improve soil health and increase establishment of desirable native grasses on degraded Army training lands. Paper was applied at rates of 9 to 72 Mg ha〈sup〉−1〈/sup〉 to two soil types at Fort Polk, LA: an alfisol (very fine sandy loam - Fine, smectitic, thermic Chromic Vertic Hapludalfs) and an ultisol (loamy fine sandy - Loamy, siliceous, semiactive, thermic Arenic Paleudults). These are common soil orders found on military training lands nationwide and represent fertile (alfisol) and unfertile (ulitsol) soils. Vegetation and soils were monitored over 2 growing seasons. No increase in heavy metals were observed in soils. Extensive analysis showed very low levels of regulated contaminants in the paper, but most were below detection limits. The ultisol site showed improved soil physical and chemical properties, while desirable vegetation benefitted from nutrient immobilization at the alfisol site. Based on the results of this study, applying pulverized paper waste to soil at a rate of 35.9 Mg ha〈sup〉−1〈/sup〉 is recommended. Application of paper waste to soils had no adverse environmental effects, improved soil physiochemical properties, and facilitated establishment of desirable native vegetation.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Nkanyiso J. Sithole, Lembe S. Magwaza〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil management practices may change soil chemical properties and thus fertility. The magnitude of change varies depending on soil type, cropping system, climate, fertilizer application and management practice. The objectives of this study were to evaluate the effects of no-till (NT), rotational tillage (RT), conventional tillage (CT) treatments, and three N-fertilizer application rates (0, 100 and 200 kg ha〈sup〉−1〈/sup〉) on soil chemical properties and maize yield in a semi-arid environment, Haplic Ferrasol in South Africa, Bergville. This was evaluated in 0–10, 10–20 and 20–30 cm depths. Soil chemical properties were measured 13 years after the implementation of the trial. Marginal differences (〈em〉p〈/em〉 〉  0.05) were found in total soil organic carbon (SOC) with NT having the highest concentration (27.1 t.ha〈sup〉−1〈/sup〉) compared to RT (26.0 t.ha〈sup〉−1〈/sup〉) and CT (26.5 t.ha〈sup〉−1〈/sup〉). The concentration of Nitrogen (N) followed the same trend (〈em〉p〈/em〉  = 0.024) where it was found to be higher under NT (1.54 t.ha〈sup〉−1〈/sup〉) than RT (1.30 t.ha〈sup〉−1〈/sup〉) and CT (1.42 t.ha〈sup〉−1〈/sup〉), respectively. SOC and N were found to be highly concentrated in the 0–10 cm depth in both NT and RT treatments. Phosphorus was significantly higher (〈em〉p〈/em〉 〈  0.001) under NT (0.0213 t.ha〈sup〉−1〈/sup〉) than RT (0.0127 t.ha〈sup〉−1〈/sup〉) and CT (0.00704 t.ha〈sup〉−1〈/sup〉). A large amount of phosphorus was in the 0–10 cm depth in NT and it was distributed more uniformly under RT and CT. Potassium was also higher (〈em〉p〈/em〉 〈  0.05) under NT (9.73 t.ha〈sup〉−1〈/sup〉) than RT (9.52 t.ha〈sup〉−1〈/sup〉) and CT (8.00 t.ha〈sup〉−1〈/sup〉). It was found to be uniformly distributed across the soil depths in all tillage treatments. No significant differences were found in the concentration of calcium across the tillage treatments, however, it was observed to increase with depth under NT and RT and to decrease with increase in depth in CT. The soil of NT and RT treatments had lower pH values (5.80 and 5.86) than CT (6.68) at 0–10 cm depth while in the lower depths, 10–20 and 20–30 cm depth was observed to increase significantly, by 1.2 and 0.9 units in NT and RT respectively. Similar trends were observed in CEC. Yield across the years averaged at 12.3, 12.4 and 11.8 t.ha〈sup〉−1〈/sup〉 in NT, RT and CT treatments respectively, under 200 kg.ha〈sup〉−1〈/sup〉 N-application. However, yields gains under NT diminished significantly than in RT and CT treatments in 100 (10.6, 11.3 and 11.4 t.ha〈sup〉−1〈/sup〉, NT, RT & CT, respectively) and 0 kg.ha〈sup〉−1〈/sup〉 N-application rate (6.6, 7.6 and 8.3 t.ha〈sup〉−1〈/sup〉, NT, RT & CT, respectively). This suggested the application of correct fertilizer proportion to increase yield. The results of this study indicated that SOC takes time to improve in conservation agricultural practices in a semi-arid environment and its increase is only confined to the soil surface. This increase in the soil surface is also associated with increased availability of the soil important nutrients which may reduce the application of these nutrients as a starter.〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 191〈/p〉 〈p〉Author(s): Raman Jeet Singh, J.S. Deshwal, N.K. Sharma, B.N. Ghosh, Ranjan Bhattacharyya〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Despite investigations suggesting that agro-geo-textiles (AGT) could be an effective and inexpensive soil conservation method, limited quantitative data are available on erosion-reducing effects of AGT under field conditions and effects on crop productivity. Field experiments (probably first of its kind) were conducted on two crop rotations during 2015-16 and 2016-17 at Dehradun on a 4% land slope in the Indian Himalayan Region (IHR). Seven treatments were executed to evaluate the conservation effects of AGT prepared from giant-cane (〈em〉Arundo donax〈/em〉) and maize (〈em〉Zea mays〈/em〉 L.) straw; and comparisons were made with coir-geo-textile, cowpea (〈em〉Vigna unguiculata〈/em〉), and grass weed vegetative filters (all placed at 1 m vertical intervals, within 100 m length plots in the rainy season maize crop) on crop productivity, profitability, runoff and soil loss reduction, and moisture conservation. During two years of experimentation, a total of 35 runoff events were observed in maize crops in rainy months (June to September). Results revealed that the highest (〈em〉p〈/em〉 〈 0.05) maize grain yield (2.8 Mg ha〈sup〉−1〈/sup〉) was recorded in 〈em〉Arundo donax〈/em〉 AGT treatment (conservation agriculture plus), which was 36% higher than maize crops raised without AGT (conservation agriculture only). This treatment also reduced runoff (24%) and conserved soil losses (8.22 t ha〈sup〉-1〈/sup〉  year 〈sup〉-1〈/sup〉) across 18 runoff events, resulting in more soil moisture conserved in the soil profile than without AGT (35 runoff events). Productivities of succeeding pea (〈em〉Pisum sativum var. hortense〈/em〉) and wheat (〈em〉Triticum aestivum〈/em〉 L. emend Fiori & Paol.) crops were enhanced by 122 and 36%, respectively, which resulted the higher net return (736 US$ ha〈sup〉−1〈/sup〉) than in a maize-pea-wheat system in conservation agriculture only (128 US$ ha〈sup〉−1〈/sup〉). In summary, conservation tillage practices along with AGT (conservation agriculture plus) are more profitable than conservation tillage practices alone on 4% land slopes of IHR.〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 191〈/p〉 〈p〉Author(s): Henrique Oldoni, Viviane Santos Silva Terra, Luís Carlos Timm, Carlos Reisser Júnior, Alex Becker Monteiro〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The soil nutritional management in peach orchards in Southern Brazil is still based on conventional and uniform recommendations, without taking into consideration the spatial variability of the physical environment. This might result in over-application of fertilizers in areas with high nutrient levels and under-application in areas with low nutrient levels, which will cause high heterogeneity in the peach production and fruit quality resulting in a low profit of farmers. The objectives of this work were to characterize the spatial variability of soil and tree attributes, in a peach orchard using classical statistics and geostatistical tools as well as to delineate potential management zones based on the soil and tree attributes using the principal component and fuzzy c-means clustering analyses. A 1.8 ha peach orchard, in Morro Redondo, State of Rio Grande do Sul, Brazil, was selected as the study area and a grid of 101 trees was established. Close to each of these trees, soil samples were collected in the 0−0.10 m and 0.10−0.20 m layers to determine sand, silt and clay fractions, soil bulk density, volumetric water content, pH in water, organic matter, available phosphorus as well as exchangeable potassium, magnesium and calcium contents. During the years of 2010, 2011 and 2012, peach yield, number of fruits per tree, average fruit weight per individual tree, flesh firmness and total soluble solids content per tree were determined. All data sets were submitted to descriptive statistics and the Kolmogorov–Smirnov test as well as to geostatistical analysis. Principal component and fuzzy c-means clustering analyses were used to delineate the management zones based on the optimal number of clusters identified employing the fuzziness performance index and the modified participation entropy. Results showed high spatial variability of yield and quality of peaches. It was found that the optimal number of management zones for the peach orchard was two and most of the soil and tree attributes presented statistical differences in each defined management zone. The defined management zones based on soil and tree attributes open the opportunity to farmers for site-specific management in the peach orchard, aiming at precision agriculture and directing soil sampling design as well.〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 191〈/p〉 〈p〉Author(s): Tina Frank, Iris Zimmermann, Rainer Horn〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Liming is a well-established practice to ameliorate acidic soils worldwide. However, the role of liming in soil structure formation and its relation to the nitrogen cycling is only little explored. We hypothesized that improved physical and mechanical soil properties, which are directly linked to soil structure, lead to lower nitrogen losses in an agricultural system. Water holding capacity, total pore volume, bulk density, hydraulic conductivity, shear stress and pre-compression stress were quantified in the topsoil of three surveys located in Germany on different soil types: Eutric Gleyic Cambisol (Loamic) (Magdeburg, Saxony-Anhalt), Haplic Luvisol (Neubrandenburg, Mecklenburg-Western Pomerania) and Eutric Cambisol (Loamic) (Puch, Bavaria). The field experiments were arranged in a Randomized Complete Block Design and treated with two different rates of lime (calcium carbonate). Furthermore, three rates of nitrogen in form of urea or calcium ammonium nitrate were applied every year. Liming significantly increased the pH, plant available water capacity, total pore volume and decreased bulk density in the soils six months after application, but twelve months after lime application the soil structure collapsed again causes by ploughing and chiseling. We, therefore, assume a positive influence of lime application on soil physical parameters, if tillage is excluded at least initially. On the other hand, our results from the shear stress parameters and the pre-compression stress values indicate that their changes need time and we assume that it may take several years to develop a sustainable structure system.〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 191〈/p〉 〈p〉Author(s): Evangelina Pareja-Sánchez, Carlos Cantero-Martínez, Jorge Álvaro-Fuentes, Daniel Plaza-Bonilla〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In newly irrigated Mediterranean agroecosystems, the combined effect of tillage and N fertilization on soil carbon dioxide (CO〈sub〉2〈/sub〉) and methane (CH〈sub〉4〈/sub〉) fluxes is at present poorly understood. The goal of this study was to quantify both soil CO〈sub〉2〈/sub〉 and CH〈sub〉4〈/sub〉 emissions as well as crop performance under different tillage systems and N fertilization rates during three maize (〈em〉Zea mays〈/em〉 L.) growing seasons (2015–2017) in a semiarid area converted to irrigated. Three types of tillage (conventional tillage, CT, reduced tillage, RT, and no-tillage, NT) and three mineral N fertilization rates (0, 200, and 400 kg N ha〈sup〉−1〈/sup〉) were compared in a randomized block design with three replications. Weekly soil CO〈sub〉2〈/sub〉 and CH〈sub〉4〈/sub〉 emissions, soil temperature and gravimetric moisture were measured. Moreover, maize above-ground biomass, grain yield, and above-ground C-inputs were quantified. Carbon dioxide emissions ranged from 173 to 4378 mg CO〈sub〉2〈/sub〉-C m〈sup〉-2〈/sup〉 d〈sup〉-1〈/sup〉. No-tillage showed a greater mean soil CO〈sub〉2〈/sub〉 flux than CT when applying the highest rate of N (400 kg N ha〈sup〉-1〈/sup〉). Although some emissions of CH〈sub〉4〈/sub〉 were observed, all treatments acted as net CH〈sub〉4〈/sub〉 sinks during most of the experimental period. A linear multiple relationship between soil CO〈sub〉2〈/sub〉 fluxes and soil gravimetric moisture (0–5 cm depth) and temperature (10 cm depth) were found. In the 2015 growing season, greater cumulative CO〈sub〉2〈/sub〉 emissions were found under NT and RT compared with CT, while in 2016 N T showed the highest values compared to CT with intermediate values in RT. Differently, in 2017 no differences between tillage systems were found. When applying N fertilizer, NT and RT increased maize grain production and above-ground C-inputs compared to CT, since a severe soil crusting occurred in this last, which caused crop water deficit. The results suggest that tillage intensity and N fertilization rate reduction can increase maize biomass production and yield which leads to greater C-input that returns to the soil.〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 191〈/p〉 〈p〉Author(s): K.C. Flower, D. Hüberli, S.J. Collins, G. Thomas, P.R Ward, N. Cordingley〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉No-tillage is a cropping system that promotes minimal soil disturbance, full residue retention and diverse crop rotation. From a disease perspective, crop rotation is one of the best control measures in no-tillage systems, as many diseases are stubble-borne. A long-term no-tillage systems experiment was conducted from 2007 to 2016 in Western Australia to test effects of crop rotation and residue amount on soil health, crop growth and yield. The current research focusses on the progression of the main stubble-borne and root diseases and plant-parasitic nematodes in this experiment. The research compared a diverse crop rotation with a ‘typical’ farmer rotation, a cereal rotation and wheat monoculture. Three-year rotations were used and the crops and cultivars were changed periodically, within the rotations, to ensure they were relevant to farmers.〈/p〉 〈p〉Levels of root lesion nematode (〈em〉Pratylenchus neglectus〈/em〉) and 〈em〉Pythium〈/em〉 increased most in the pasture and diverse rotations, followed by the wheat monoculture and appeared to decrease slightly in the farmer and cereal rotations. The combination of canola and wheat, along with susceptible chickpea, appeared to favour root lesion nematode. In contrast, fallow and lupin in the farmer rotation appeared most effective at reducing levels. The relatively high numbers of 〈em〉P〈/em〉. 〈em〉neglectus〈/em〉 in the pasture was likely due to continuous presence of a number of susceptible weeds and subterranean clover. The crop selections in the diverse rotation of this experiment have generally been a poor choice in terms of 〈em〉P. neglectus,〈/em〉 the main nematode threat in Western Australia.〈/p〉 〈p〉By 2016, there was significantly greater 〈em〉Rhizoctonia solani〈/em〉 in the soil following cereals compared with canola, chickpea and fallow. Nonetheless, the break crops appeared to have had a relatively short term effect on amounts of 〈em〉R. solani〈/em〉.〈/p〉 〈p〉Over the nine years, 〈em〉Fusarium〈/em〉 spp. DNA in the soil increased most in the cereal rotation and wheat monoculture; it hardly changed in the farmer rotation and pasture and it declined in the diverse rotation.〈/p〉 〈p〉There was a decrease in 〈em〉Didymella pinodes〈/em〉/〈em〉Phoma medicaginis〈/em〉 var 〈em〉pinodella〈/em〉 DNA (causing pea black spot) in the cereal rotation, farmer rotation and wheat monoculture. In contrast, there was a small increase in pea black spot pathogen DNA in the diverse rotation. This generally reflected the number of pea crops grown, except for the farmer rotation, which had peas grown at the same intensity as the diverse rotation. The difference between these two rotations was likely due to the lower amounts of residue in the farmer rotation, which had fallow and tillage since 2013. As expected, there were higher incidence of the stubble-borne disease in wheat and barley when following the same type of crop. Crop residue management, by windrow burning, had little effect on the level of leaf, root or crown diseases.〈/p〉 〈p〉The differences in host status between crop types and even varieties means that farmers require up-to-date information on the host status if rotations are going to be effective in reducing a broad range of plant-parasitic nematodes and pathogens in soils with no-tillage.〈/p〉 〈/div〉

Description: 〈p〉Publication date: May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 188〈/p〉 〈p〉Author(s): Songchao Chen, Dominique Arrouays, Denis A. Angers, Manuel P. Martin, Christian Walter〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Increasing soil organic carbon (SOC) stocks via land management has been proposed as a temporary climate change mitigation measure. An upper limit of soil stable SOC storage, which refers to the concepts of SOC saturation has been proposed. Using systematic grid sampling of topsoil in mainland France and an equation that predicts this SOC saturation, we derived estimates of the SOC sequestration potential density (SOC〈sub〉spd〈/sub〉) for various land uses. First, using French database and data from the literature we estimated the proportions of the SOC stored in the fine fraction (SOC〈sub〉fine〈/sub〉) in total SOC for grassland (69%), cropland (85%) and forest (66%). Then, SOC〈sub〉spd〈/sub〉 was calculated as the difference between the theoretical SOC saturation value and SOC〈sub〉fine〈/sub〉. The SOC〈sub〉spd〈/sub〉 stocks for French topsoil were estimated at about 1.1 Pg, in which cropland, forest and grassland accounted for 66%, 17% and 17%, respectively. Varying the proportions of SOC〈sub〉fine〈/sub〉 in the calculations by assuming a possible range of 0.8-0.9 for cropland and 0.6-0.9 for grassland and forest soils led to variations of total SOC〈sub〉spd〈/sub〉 stocks of about 0.1 Pg for each land use. Most importantly, we demonstrate that the distribution of SOC〈sub〉spd〈/sub〉 in forest soils is exactly centred at zero, which suggests that on average, forest topsoils are saturated in SOC〈sub〉fine〈/sub〉, and thus Hassink’s equation provides a valid estimate for the SOC sequestration potential for French topsoil.〈/p〉〈/div〉

Description: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 189〈/p〉 〈p〉Author(s): Jaqueline A.R. Borges, Luiz F. Pires, Fábio A.M. Cássaro, André C. Auler, Jadir A. Rosa, Richard J. Heck, Waldir L. Roque〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The sustainability and efficiency of crop production are sometimes dependent on the adopted tillage system. In Brazil, conservation systems such as no-tillage (NT) have been adopted as an alternative to conventional tillage (CT) method. Conservation tillage systems usually tend to minimize soil losses, water runoff, preserve soil moisture and reduce the disruption of the soil structure. Nevertheless, the influence of these managements in the soil porous system, in the micrometric point of view, is not presented in most of the published literature. Considering the importance of pores for the proper functioning of the soil, the main objective of this study was to analyze the effect of long-term NT and CT systems, in comparison to non-managed soil maintained under secondary forest (F) conditions on the pore system of a clay soil, using 3D X-ray computed tomography (μCT) images. To achieve this goal, 3D μCT images were obtained from samples of the surface soil (0.05-0.10 m and 0.10-0.15 m). Morphological attributes such as: macroporosity (MAP), number of macropores (NMAP), shape of pores, tortuosity (τ) and connectivity (C), estimated based on the Euler-Poincaré characteristic (EPC), were employed to characterize the soil porous system. In addition, saturated hydraulic conductivity (K〈sub〉s〈/sub〉) and soil water retention curve (SWRC) were analyzed. The forest was characterized by the highest MAP. However, when comparing the tillage systems, the CT MAP was larger than that of NT. K〈sub〉s〈/sub〉 showed the same trends, which indicates that K〈sub〉s〈/sub〉 was directly influenced by MAP. However, SWRC analyses showed a greater volume fraction of mesopores and micropores under NT than under CT. The macropore size distribution reveals that large well-connected macropores (volume 〉1000 mm〈sup〉3〈/sup〉) were responsible for the major contribution to MAP. However, the highest contribution to NMAP was given by macropores with volume up to 0.1 mm〈sup〉3〈/sup〉. Tortuosity results indicate less sinuous pores for F, when compared to CT and NT. EPC results present better connectivity of pores in the shallow layer 0.05-0.10 m for F, while the opposite was observed for CT. The present research showed that from 3D μCT images, associated with results of hydraulic properties, it is possible to characterize the macroporous system of undisturbed samples. Research like this is important to infer about the impacts of management systems on soil.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 195〈/p〉 〈p〉Author(s): Gábor Szatmári, Béla Pirkó, Sándor Koós, Annamária Laborczi, Zsófia Bakacsi, József Szabó, László Pásztor〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We compiled maps for the topsoil (0–30 cm) organic carbon (SOC) stock and its prediction uncertainty in Hungary at 100 m resolution for the years 1992 and 2010 using a machine learning algorithm, namely, quantile regression forest. 10-fold cross-validation was used for checking the accuracy of the spatial predictions and uncertainty quantifications for both years. The performance of the spatial predictions and uncertainty quantifications was appropriate, which was verified by the computed biases (0.15 and 0.30 for 1992 and 2010), root mean square errors (21.99 and 21.39 for 1992 and 2010), accuracy plots and the G statistics (0.96 for both years) as well. Based on the compiled SOC stock maps, we assessed the spatio-temporal change of SOC stocks on the territory of Hungary. A scheme was elaborated based on the quantified prediction uncertainties for identifying and delimiting significant and tendentious changes of SOC stock during the respective period. The total SOC stock in the topsoil was found to be 424.41 Tg (1 teragram = 10〈sup〉12〈/sup〉 grams) in 1992 and 451.59 Tg in 2010. Thus SOC stock increased by 27.18 Tg over the respective period. On those areas where the land use types did not change, we observed that the SOC stock increased under forests (by 16.29 Tg) and pastures (by 2.48 Tg), decreased under wetlands (by 0.49 Tg) and did not change under agricultural areas. On those areas where the land use has been changed during the 18-year period, we found that afforestation has increased the SOC stock, whereas cultivation of pastures has decreased it. Due to soil sealing 34,000 ha of soil have been lost resulting in approximately 1.7 Tg carbon loss. We compared our own total SOC stock estimate and map referring to 1992 with other estimates and maps provided by global and continental initiatives. The comparisons have pointed out that the SOC stock map of 1992 outperformed these maps. We recommend applying the SOC stock map of 1992 as a baseline for Hungary.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0167198719301448-ga1.jpg" width="417" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 195〈/p〉 〈p〉Author(s): Qiaoyi Huang, Xiaolin Fan, Shuanhu Tang, Mu Zhang, Xu Huang, Qiong Yi, Yuwan Pang, Jianfeng Huang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Single basal application of bulk blending urea(BBU) which consists of both controlled-released urea(CRU) and conventional urea(U) has been proposed to facilitate fertilization and lower cost of CRU. Nevertheless, its effect on the growth, yield and N use efficiency(NUE) of rice in double rice cropping system under subtropical environment are still unknown. Field experiments were conducted at two different sites(Taishan county and Wengyuan county) simultaneously in Guangdong province to investigate the effects of single basal application of two types of BBU(P-BBU which consists of parabolic pattern CRU, and S-BBU which consists of sigmodial pattern CRU) on soil available N, grain yield and NUE. Conventional high-yield fertilization treatment with four split applications of U(FP) and no-N treatment(CK) were established as controls. The results demonstrated that BBU could provide similar or more adequate N nutrient for rice with FP during late rice season. BBU performed comparably to or better than FP on soil NH〈sub〉4〈/sub〉〈sup〉+〈/sup〉-N, dry matter, grain yield and NUE during late rice season. During early rice season, BBU performed comparably with FP on soil NH〈sub〉4〈/sub〉〈sup〉+〈/sup〉-N, N content of rice, dry matter, grain yield and NUE at Taishan site, while at Wengyuan site, it significantly reduced soil NH〈sub〉4〈/sub〉〈sup〉+〈/sup〉-N, N content of rice, dry matter and NUE compared with FP, and reduced grain yield slightly. Release tests in water and paddy field were conducted in order to evaluate the releasing dynamics of parabolic and sigmodial pattern CRU. Results showed that the N release rate of CRU in paddy field during early rice season was significantly slower than that during late rice season. This was closely correlated with the changing pattern of accumulated temperature. The N release rate of parabolic CRU in paddy field was faster and more sensitive to changing temperature than sigmodial CRU. Non-linear regression analysis shows that the N release patterns of sigmodial CRU in paddy fields were more close to N uptake of rice during both rice seasons. The grain yield of rice and NUE in S-BBU was higher slightly than P-BBU during both rice seasons. These results demonstrated that BBU obtained similar grain yield in double rice cropping system in South China, and S-BBU treatment is better for N requirement of rice during both seasons. Future studies should focus on optimizing and customizing the blending ratio of BBU for each rice season in double rice cropping system to increase crop yield and the robustness of BBU to changing weather conditions.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 195〈/p〉 〈p〉Author(s): Juan Song, Yanyan Han, Bianxia Bai, Shan Jin, Qingfang He, Jiahong Ren〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The diversity of arbuscular mycorrhizal fungi (AMF) of 〈em〉Sophora flavescens〈/em〉 was studied in the prefecture-level cities of Changzhi and Jincheng in Shanxi Province, China, based on their relationship to the soil environment and elevation. Rhizosphere soils were investigated by Illumina MiSeq technology. In total, 220 AMF operational taxonomic units were detected, representing eight families and 14 genera. 〈em〉Glomus〈/em〉, 〈em〉Septoglomus〈/em〉, 〈em〉Rhizophagus〈/em〉, 〈em〉Kamienskia〈/em〉 and 〈em〉Sclerocystis〈/em〉 were the dominant AMF genera in the root zone of 〈em〉S. flavescens.〈/em〉 In addition, the content of glomalin-related soil proteins was measured to assess AMF biomass. Soil type determined the distribution of AMF communities in 〈em〉S. flavescens〈/em〉 field soils, and this effect was attributed to soil properties related to total nitrogen, available phosphorus concentration, invertase, soil organic matter and urease. Our results support the hypothesis that concentrations of soil chemicals and host plant can exert a selective effect on the composition of the AMF population in the soil surrounding 〈em〉S. flavescens.〈/em〉〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Relative abundance of members of families belonging to the division Glomeromycota at each site are presented in terms of the number of reads per family. Only the top 20 OTUs and the horizontal heatmap are shown. Rhizosphere soils were investigated by Illumina MiSeq technology. In total, 220 AMF operational taxonomic units were detected, representing eight families and 14 genera. 〈em〉Glomus〈/em〉, 〈em〉Septoglomus〈/em〉, 〈em〉Rhizophagus〈/em〉, 〈em〉Kamienskia〈/em〉 and 〈em〉Sclerocystis〈/em〉 were the dominant AMF genera in the root zone of 〈em〉S. flavescens.〈/em〉〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0167198718311966-ga1.jpg" width="218" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 195〈/p〉 〈p〉Author(s): Rainer Horn, Dörthe Holthusen, José Dörner, Anneka Mordhorst, Heiner Fleige〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Due to the need of securing food production for a growing world population, modern agriculture enhances the risk of land degradation. Thus, knowledge of biological, chemical and physical soil properties and processes under in situ conditions at all scales are needed to give a precise quantification of relevant soil functions. Scenarios for political discussions must be included. Parameters and their boundary conditions need to be defined. These parameters include the interparticle forces on the micro-scale, which are determined by the zeta potential and rheological properties. They are affected by matric potential and organic carbon. In addition, fertilizer application (amount and composition) and micro (aggregate) stability, which includes the processes of repulsion and dispersion, affect these forces. The latter are strongly related to the ionic composition and concentration. Strengthening processes can be also documented on the meso- and macroscale. On all scales, we need to regard tensorial properties and functions, as they also serve as a feedback mechanism for anthropogenic effects including changes in fluxes, accessibility of particle or pore surfaces for filter and buffer processes, or plant growth. Land use affects the physical soil functions, which may result in yield decline, enhanced gas emission, enhanced soil erosion, or more frequent flooding, if the rigidity of the pore system is not maintained. Soil degradation due to inadequate management mainly occurs when the internal soil strength (i.e., the precompression stress range, as its transitions from the recompression to the virgin compression range) is exceeded. The degradation can occur with any stress whether it is static or dynamic or mechanical or hydraulic. In the field, it can be verified by visible deformation (as a result of too much traffic) and, by means of critical physical values, the consequences on soil functions can be estimated using Compaction Verification Tools (CVT) that document harmful (subsoil) compaction.〈/p〉 〈p〉Thus, to avoid irreversible soil degradation because of subsoil compaction, precompression stress values (or ranges), in combination with hydraulic conductivity and air capacity values, are suggested to be the basis for values used in the German soil-protection law.〈/p〉 〈/div〉

Description: 〈p〉Publication date: February 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 196〈/p〉 〈p〉Author(s): Ziting Wang, Tong Li, Yuze Li, Deqiang Zhao, Juan Han, Yang Liu, Yuncheng Liao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present study investigates the microbial (bacterial and fungal) community diversity and carbon substrates utilization in rhizosphere and bulk soil under three tillage practices (chisel plow, zero, and plow tillage) by using high-throughput sequencing technology and community-level physiological profiles. Conservation tillage practices increased the DOC, SOC, and invertase activity in bulk soil compared with conventional tillage. Tillage disturbances changed the soil microbial phylogenetic composition and utilization abilities of carbon substrates, and there was a significant positive correlation between soil microbial alpha diversity and catabolic diversity under different tillage practices. The soil microbial phylogenetic composition was significantly different with different soil types (rhizosphere and bulk) under three tillage practices, which had great influence on carbon substrate utilization. The soil physicochemical parameters were significantly correlated with microbial taxonomy composition. Structural equation model (SEM) analysis suggested that the relative abundances of Proteobacteria (Alpha- and Betaproteobacteria), Bacteroidetes, Capnodiales, and Pleosporales in the rhizosphere helped in the utilization of amino acids, carbohydrates, and carboxylic acid under different tillage practices. Our results suggested that conservation tillage practices and crop root activities modified soil physicochemical parameters and enrich soil nutrient conditions, which contributes to differences of soil microbial phylogenetic and taxonomic compositions, thereby increasing copiotrophic microbial populations in the rhizosphere and enhances metabolic capacities. Thus, these results can improve our understanding of the roles of conservation tillage in changing soil microbial community and catabolic diversity, as well as can help to establish a profitable agroecosystem to enhance soil nutrient conditions and modify soil microbial ecology, in turn improving plant production sustainability.〈/p〉〈/div〉

Description: 〈p〉Publication date: February 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 196〈/p〉 〈p〉Author(s): Longshan Zhao, Rui Hou, Faqi Wu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In many studies, the role of tillage-induced surface microrelief (TSM) in water erosion was assessed by comparing the changes in microrelief indexes during rainfall estimated from a digital elevation model (DEM). Accurate quantification of microrelief indexes is essential because it was said that DEM resolution affects microrelief indexes. The objective of this study was to estimate several common microrelief indexes (tortuosity index (〈em〉T〈sub〉B〈/sub〉〈/em〉), maximum depression storage (MDS), depression volume, depression area ratio and surface microrelief slope) and determine how DEM resolution affects these indexes. Surface elevation data of three surface slopes were collected using a laser scanner from 1-m-wide by 2-m-long plots after reservoir tillage. A series of DEMs with grid sizes of 1, 2, 4, 6, 8, 10, 20, 40 and 60 mm were generated based on the interpolation method. Our results showed that 〈em〉T〈sub〉B〈/sub〉〈/em〉 decreased with increasing grid size, while no significant differences were measured among the small grid sizes; overall, the MDS and depression volume remained steady regardless of DEM grid size, meaning that the effects of grid size on the MDS and depression volume are very small; the depression area ratio decreased with increasing grid size. As the grid size increased, the number of steep slopes decreased, while gentle and medium slopes exhibited increasing surface microrelief slopes. Therefore, on reservoir tillage-treated slopes, the effects of grid size on microrelief indexes differed due to their different physical meanings. Based on our results, it is better to maintain a grid size of 20 mm or smaller when estimating DEM-based microrelief indexes.〈/p〉〈/div〉

Description: 〈p〉Publication date: February 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 196〈/p〉 〈p〉Author(s): Peter Riegler-Nurscher, Gerhard Moitzi, Johann Prankl, Josef Huber, Jürgen Karner, Helmut Wagentristl, Markus Vincze〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To address inhomogeneous soil properties during seedbed preparation, a system for site-specific tillage is proposed. The aim of this study was to develop a system to control the rotational speed of the power harrow based on visual detection of the soil roughness with a stereo camera. The basis for the control is the causal relationship between the measurement of soil roughness with stereo cameras, tillage intensity and the aggregate size distribution through dry sieving of the top seedbed. The stereo camera based roughness measurement system developed during this study, focused on robustness and real-time capabilities. Environmental influences on the measurement system were investigated and countermeasures were implemented. The measurement system outputs a roughness index which was the input for a control algorithm. The system was integrated into an ISOBUS Class III application which controls the PTO speed of a tractor in order to prepare a homogeneous soil roughness. During tests several seedbeds with different roughness were prepared with a power harrow following different primary tillage operations. The results of the study have been the basis for the development of a control-approach. The correlations between the aggregate size measured with sieve analysis and soil roughness measured by the stereo vision system was estimated to evaluate the system. Additionally, the comparison between soil roughness and tillage intensity showed high correlation. During validation of the controller, the homogenizing effect on the soil roughness could be shown.〈/p〉〈/div〉

Description: 〈p〉Publication date: February 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 196〈/p〉 〈p〉Author(s): Hua Zhou, Chunling Zhang, Wenliang Zhang, Quanjun Yang, Dong Li, Zhengyuan Liu, Junfang Xia〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Straw incorporation into the soil can effectively solve the problem of extra harvested crop residues on the surface. However, due to the lack of research on the spatial distribution effects of straw in the soil after incorporation, it is difficult to evaluate the actual straw incorporation effects of tillage tools. In this study, straw incorporation experiments were conducted via three types of tillage tools in rice stubble fields: a traditional rotary tiller (TR), a straw rotary burying and returning machine (SR) developed by our research group, and a subsoiling + straw rotary burying and returning machine (SSR). The same operating parameters, such as working speed and tillage depth, were used in the experiments. The spatial distribution of straw after tillage tool operation was measured and compared by a measuring device developed for straw three-dimensional coordinates. The results showed that after TR operation, the cutting effect on the straw was poor; more straw was left on the surface and less straw was buried into the lower layer of the tillage depth compared to SR and SSR; the average length of straw in the divided cells was small; and there were many cells without straw. Compared with that of TR, the straw average length of SR and SSR decreased by 48.2% and 52.7%, respectively. Only a small amount of straw remained on the surface. The proportion of straw in the lower layer of the tillage depth increased by 154.9% and 214.1%, the average straw length in cells increased by 114.9% and 98.6%, and the number of cells without straw decreased by 40.2% and 36.0%, respectively. On the whole, SR and SSR had more advantages for straw cutting and straw incorporation into the soil, and SSR could bury more straw into the soil of the lower layer. Therefore, for fields with excessive residue concerns, the SSR was the most desirable tillage tool.〈/p〉〈/div〉

Description: 〈p〉Publication date: February 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 196〈/p〉 〈p〉Author(s): Yushu Zhang, Xiangzhou Zheng, Baoling Guo, Juhua Yu, Alison Carswell, Tom Misselbrook, Jinbo Zhang, Christoph Müller, Deli Chen, Hong Ding〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The effectiveness of rice-straw incorporation to alleviate environmental deterioration and increase soil fertility is widely accepted, whereas, the effect of this management on stimulating soil nitrogen (N) transformation is not fully understood. This study was conducted to investigate the effect of rice-straw incorporation on soil N transformation. An incubation experiment was conducted with rice-straw incorporated at rates of 0 (RS0), 1.67 (RS1), 3.33 (RS2) and 6.67 g kg〈sup〉−1〈/sup〉 soil (RS3). Tracing experiments with 〈sup〉15〈/sup〉NH〈sub〉4〈/sub〉NO〈sub〉3〈/sub〉 and NH〈sub〉4〈/sub〉〈sup〉15〈/sup〉NO〈sub〉3〈/sub〉 was conducted in the first (Week 1) and tenth week (Week 10) after straw incorporation, and a numerical model was used to calculate gross rates of N transformations. Incorporation of rice-straw increased gross rates of soil organic N mineralization, ammonium (NH〈sub〉4〈/sub〉〈sup〉+〈/sup〉) and nitrate (NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉) immobilization and oxidized organic-N to NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉, by 0.2–1.7 times, 4.6–11.6 times, 20.4–74.9 times and 6.2–20.3 times, respectively. However, the stimulation of soil N transformation via rice-straw incorporation was insignificant by week 10. Over the incubation period, the stimulation of soil inorganic N production pathways (organic N mineralization and oxidized organic-N to NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉) via rice-straw incorporation was less than on consumption pathways (NH〈sub〉4〈/sub〉〈sup〉+〈/sup〉 and NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉 immobilization), leading to soil inorganic N supply capacity decreasing with straw incorporation rates. Dissimilatory NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉 reduction to NH〈sub〉4〈/sub〉〈sup〉+〈/sup〉 was stimulated by rice-straw incorporation, as observed in both the first and tenth week. Compared with RS0, autotrophic nitrification decreased by 14%, 25% and 46% in RS1, RS2 and RS3, respectively, but this effect disappeared by week 10. However, nitrification capacity (〈em〉NC〈/em〉, the ratio of autotrophic nitrification rate to total mineralization rate) was constrained following rice-straw incorporation both in the first and tenth weeks. Decreasing autotrophic nitrification was the most important factor contributing to decreased NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉 content with straw incorporation, followed by increasing NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉 immobilization. The gross rate of autotrophic nitrification was negatively correlated with NH〈sub〉4〈/sub〉〈sup〉+〈/sup〉immobilization, indicating that autotrophic nitrification inhibition may be attributed to increased NH〈sub〉4〈/sub〉〈sup〉+〈/sup〉 immobilization. Therefore, based on the observations of this study, rice-straw incorporation is recommended for reducing nitrification capacity and reducing risks of N losses in subtropical acid soil.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S016719871930947X-ga1.jpg" width="249" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: February 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 196〈/p〉 〈p〉Author(s): Maroua Dachraoui, Aurora Sombrero〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In recent decades, the agricultural sector contributed to the increase of the greenhouse gases (GHGs) concentrations into the atmosphere. Soil management and the use of high amounts of energy (direct and indirect) contribute significantly to these emission〈u〉s.〈/u〉 This work aims to estimate the carbon footprint (C footprint) in two different soil managements in continuous irrigated maize, conventional (CT) and no tillage (NT), using different nitrogen fertilisation rates. The study was carried out from 2011 to 2017, in Zamadueñas experimental field in the Spanish province of Valladolid. The design included blocks randomly chosen, where the main factor studied was tillage system and the second was the nitrogen fertilisation. Under CT, the seedbed was prepared with a mouldboard plough (at a depth of 30 cm) followed by a spring cultivator, while only an herbicide was applied under NT system. In 2012/2014, N-fertilisation included the application of 700 (FC) and 600 (FR) kg ha〈sup〉−1〈/sup〉 of Calcium Ammonium Nitrate 27%. In 2015/2017, it consisted of 700 kg ha〈sup〉−1〈/sup〉 (FC) of NAC 27%, 700 (FE) and 600 (FER) kg ha〈sup〉−1〈/sup〉 of Ammonium Sulfate Nitrate 26%. The assessment of CO〈sub〉2〈/sub〉 emissions depended on the analysis of the energy consumed and produced in the maize production process and on the amount of soil organic carbon (SOC) obtained by collecting soil samples at three depths 0–10, 10–20, and 20–30 cm in 2011 and were after re-sampled at 2 years intervals. N〈sub〉2〈/sub〉O emissions estimation was based on the methodology suggested by IPCC (2006). The results obtained showed that maize C footprint was mainly due to direct and indirect N〈sub〉2〈/sub〉O emissions produced by the application of synthetic fertilisers and ranged from 3.3 to 4.2 tCO〈sub〉2eq〈/sub〉 ha〈sup〉-1〈/sup〉 and from 3.4 to 4.4 tCO〈sub〉2eq〈/sub〉 ha〈sup〉-1〈/sup〉 under CT and NT management respectively. The highest N〈sub〉2〈/sub〉O emissions were produced by the use of FC and FE fertilisation while FR and FER resulted in the lowest N〈sub〉2〈/sub〉O emissions under both tillage treatments. The emissions resulting from the energy inputs of electricity, fuel combustion and agricultural machinery contributed to the C footprint with means ranging from 0.25 to 0.27 tCO〈sub〉2eq〈/sub〉 ha〈sup〉-1〈/sup〉 and from 0.23 to 2.25 tCO〈sub〉2eq〈/sub〉 ha〈sup〉-1〈/sup〉 under CT and NT system respectively during the 6-year study. SOC changes played a very important part in the quantification of maize C footprint as they reversed the results from high and positive when the calculation excluded the SOC to low and negative when the SOC was included.〈/p〉〈/div〉

Description: 〈p〉Publication date: February 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 196〈/p〉 〈p〉Author(s): Eeusha Nafi, Heidi Webber, Isaac Danso, Jesse B. Naab, Michael Frei, Thomas Gaiser〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Loss of topsoil, enriched with nutrients, reduces soil fertility, and is one of the major impediments to sustainable crop production in West Africa. Appropriate management practices can lead to a stable restoration of land’s capacity to provide adequate ecosystem services. Thus, our study aimed to investigate the impact of alternative management practices and their interactions on topsoil (0–20 cm) organic carbon (SOC〈sub〉d〈/sub〉), nutrient stocks [total nitrogen (STN〈sub〉d〈/sub〉), phosphorus (SP〈sub〉d〈/sub〉) and potassium (SK〈sub〉d〈/sub〉)] under a maize-cotton rotation system on highly weathered soils of West Africa. To this end, on-farm trials were set up on four sites in the sub-humid Savanna of West Africa (2 in Benin (St1 and St2), and 2 in Burkina-Faso (St3 and St4)) in a strip-split plot layout, where 2 levels of tillage (contour ridge tillage, Ct and reduced tillage, Rt) were considered as main plot factor, and sub-plot factors included 2 levels of crop residue management (removed, CRr and incorporated, CRi), and 2 levels of N fertilizer (control, N0 and recommended rate, Nr). In 2016, after 5 cycles of annual maize-cotton rotation (2012–2016), the largest pool of soil nutrients was recorded on St3 (Haplic Lixisol, footslope in Benin), while the lowest content was observed on St1 (Ferric Lixisol, footslope in Burkina). When comparing the treatments, we found that Ct combined with CRi improved soil nutrient stocks in upslope sites, St2 (Eutric Plinthosol, upslope in Burkina) and St4 (Plinthic Lixisol, upslope in Benin), which are more prone to erosion. At the same time, footslope sites (St1 and St3) benefited from Rt coupled with CRi. CRi promoted an increase in SP〈sub〉d〈/sub〉 and SK〈sub〉d〈/sub〉 on all sites except St1 (Haplic Lixisol on footslope). The application of recommended dose of N fertilizer improved STN〈sub〉d〈/sub〉 under the Ct system in upslope regions and under the Rt system in footslope regions. However, no significant difference was observed for soil pH among the treatments across all sites. In summary, the efficiency of practices for conservation of soil nutrient stocks was closely related to landscape position of the field, which was correlated with soil moisture, textural class, and gravel content. Consequently, site-adapted tillage practices combined with residue incorporation are crucial for sustainable soil fertility management and crop productivity under maize-cotton rotation in smallholder production systems in West Africa.〈/p〉〈/div〉

Description: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 198〈/p〉 〈p〉Author(s): Wenru Jia, Chunlai Zhang, Xueyong Zou, Liqiang Kang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Through wind tunnel experiments, we measured the surface shear stress (τ〈sub〉s〈/sub〉) on a bed surface that contained widely but uniformly spaced non-erodible ridges. We found that when the ridge spacing is larger than 10 times the height (〈em〉H〈/em〉), the τ〈sub〉s〈/sub〉 between two adjacent ridges could be divided into two sections. In each section, shear stress gradually increases and then decreases. The first section appears to be produced by the reverse-flow vortex that develops close behind upwind ridges and the second appears to result from airflow recovery followed by blockage by the downwind ridge. The mean surface shear stress (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.svg"〉〈mover accent="false"〉〈mrow〉〈msub〉〈mtext〉τ〈/mtext〉〈mtext〉s〈/mtext〉〈/msub〉〈/mrow〉〈mo〉¯〈/mo〉〈/mover〉〈/math〉) of the total bed increases with increasing ridge spacing and friction velocity, and decreases with increasing ridge density. The spatial differences in τ〈sub〉s〈/sub〉 lead to a non-uniform distribution of wind erosion between the ridges. Based on the threshold shear stress (τ〈sub〉t〈/sub〉) of the tested soil, we revealed a regular distribution of effective shear stress (τ〈sub〉eff〈/sub〉) on the sand bed, and established quantitative relationships among mean effective shear stress (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si3.svg"〉〈mover accent="false"〉〈mrow〉〈msub〉〈mtext〉τ〈/mtext〉〈mrow〉〈mtext〉e〈/mtext〉〈mtext〉f〈/mtext〉〈mtext〉f〈/mtext〉〈/mrow〉〈/msub〉〈/mrow〉〈mo〉¯〈/mo〉〈/mover〉〈mo stretchy="false"〉)〈/mo〉〈/math〉, 〈em〉H〈/em〉, ridge spacing (〈em〉L〈/em〉), friction velocity (〈em〉u〈/em〉〈sub〉*〈/sub〉), and the threshold friction velocity (〈em〉u〈/em〉〈sub〉*t〈/sub〉) for sand entrainment: 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si4.svg"〉〈mover accent="false"〉〈mrow〉〈msub〉〈mtext〉τ〈/mtext〉〈mrow〉〈mtext〉e〈/mtext〉〈mtext〉f〈/mtext〉〈mtext〉f〈/mtext〉〈/mrow〉〈/msub〉〈/mrow〉〈mo〉¯〈/mo〉〈/mover〉〈mo〉=〈/mo〉〈mi〉a〈/mi〉〈mi〉L〈/mi〉〈msqrt〉〈mi〉H〈/mi〉〈/msqrt〉〈msup〉〈mrow〉〈mfenced close=")" open="("〉〈mrow〉〈msub〉〈mi〉u〈/mi〉〈mi〉*〈/mi〉〈/msub〉〈mo〉-〈/mo〉〈msub〉〈mi〉u〈/mi〉〈mrow〉〈mi〉*〈/mi〉〈mtext〉t〈/mtext〉〈/mrow〉〈/msub〉〈/mrow〉〈/mfenced〉〈/mrow〉〈mn〉2〈/mn〉〈/msup〉〈/math〉.〈/p〉〈/div〉

Description: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 198〈/p〉 〈p〉Author(s): Rafael Villarreal, Luis Alberto Lozano, María Paz Salazar, Guido L. Bellora, Esteban M. Melani, Nicolás Polich, C. Germán Soracco〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil hydraulic properties and pore system configuration are important parameters to understand soil physical behavior under different tillage systems. However, there are some contradictory results, including the influence of soil type on the temporal variation of these properties during the crop cycle. The aim of this work was to determine soil hydraulic properties and soil pore system configuration in different sampling dates during the crop cycle under no tillage (NT) and conventional tillage (CT) in three representative soil types from Argentinean Pampas Region. Soil hydraulic conductivity at different tensions, pore size distribution (PoSD), water-conducting porosity and soil pore connectivity were determined in a loam Abruptic Argiudoll (Chascomús site, CHA); a silty loam Typic Argiudoll, (Pergamino site, PER); a sandy loam Entic Haplustoll (Dorila site, DOR), under NT and CT. Temporal trends of soil hydraulic properties were different in each site, depending on the tillage system. PoSD and hydraulic properties showed more pronounced temporal changes in CHA and PER as compared with DOR. Mean values of K〈sub〉0〈/sub〉 ranged between 0.47 and 3.85 cm h〈sup〉−1〈/sup〉, corresponding to PER, under NT, and CHA, under CT, respectively. CT treatment presented higher values of hydraulic conductivity and water-conducting macroporosity, especially between spring and summer, related to higher biological activity, except in PER. It was observed that tillage can increase temporally the values of total macroporosity, while the biological activity during the growing period increases the connectivity of soil macropores, improving water transport.〈/p〉〈/div〉

Description: 〈p〉Publication date: February 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 196〈/p〉 〈p〉Author(s): Peng Zhao, Jukka Pumpanen, Shaozhong Kang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An investigation of soil respiration (〈em〉R〈sub〉s〈/sub〉〈/em〉) is critical to determining the CO〈sub〉2〈/sub〉 emissions and carbon balance in grapevines, but unfortunately, there is a lack of information about the magnitude of vineyard 〈em〉R〈sub〉s〈/sub〉〈/em〉 and the effects of cultivation practices and environmental factors on this important process. The objective of the present study was to evaluate the spatial and temporal variability and controls of 〈em〉R〈sub〉s〈/sub〉〈/em〉 in a furrow-irrigated vineyard. An automatic CO〈sub〉2〈/sub〉 exchange system was used to measure 〈em〉R〈sub〉s〈/sub〉〈/em〉 for a three-year period. The hourly 〈em〉R〈sub〉s〈/sub〉〈/em〉 ranged between 0.45–2.20 μmol m〈sup〉−2〈/sup〉 s〈sup〉−1〈/sup〉 on the ridge and between 0.23–1.62 μmol m〈sup〉−2〈/sup〉 s〈sup〉−1〈/sup〉 in the furrow, respectively. The spatio-temporal variability in 〈em〉R〈sub〉s〈/sub〉〈/em〉 was mainly affected by soil temperature, and soil moisture played a second role. This study failed to separate 〈em〉R〈sub〉s〈/sub〉〈/em〉 into the autotrophic and heterotrophic components by measuring 〈em〉R〈sub〉s〈/sub〉〈/em〉 in the plant and bare areas, which could be attributed to the deeper distribution of grape roots as well as the fewer root biomass. Continuous measurement of houly 〈em〉R〈/em〉〈sub〉s〈/sub〉 showed statistically non-significant differences before and after irrigation in the furrow and on the ridge, respectively. The diel hysteresis between soil respiration and temperature was found in our study. The shape and direction of the hysteresis loops and the time lag were mainly influenced by soil moisture. Finally, based on an empirical temperature-moisture model, the vineyard seasonal total and daily average 〈em〉R〈sub〉s〈/sub〉〈/em〉 were estimated to be 470.6, 461.4 and 495.4 g CO〈sub〉2〈/sub〉 m〈sup〉−2〈/sup〉, and 2.83, 2.64, and 2.74 g CO〈sub〉2〈/sub〉 m〈sup〉−2〈/sup〉 day〈sup〉−1〈/sup〉 in 2013, 2014 and 2015, respectively.〈/p〉〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 190〈/p〉 〈p〉Author(s): S.G. Mudarisov, I.I. Gabitov, Y.P. Lobachevsky, N.K. Mazitov, R.S. Rakhimov, R.R. Khamaletdinov, I.R. Rakhimov, I.M. Farkhutdinov, A.M. Mukhametdinov, R.T. Gareev〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The purpose of the research is to develop a model of the technological process of tillage, justify the initial and boundary conditions for the functioning of the model and determine the ratio of the physical and mechanical properties of the soil and the viscosity of the medium.〈/p〉 〈p〉As a model of the soil medium, it was proposed to use the rheological model of Newtonian viscous fluid, which allows using the methods of continuous media dynamics for modeling the technological process of soil treatment, and computational fluid dynamics for numerical implementation of the model. The initial and boundary conditions for the functioning of the model are substantiated and the ratio of the physical and mechanical properties of the soil and the viscosity of the medium are found. The results of determining the traction resistance of the tool and their comparison with the results obtained during laboratory experiments on the soil channel are presented. The proposed method of modeling the soil treatment allows you to analyze the power characteristics of the working bodies and the quality of the soil at the design stage of tillage machines. The obtained characteristics make it possible to optimize the structural and technological parameters of the working bodies of machines on the computer.〈/p〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 190〈/p〉 〈p〉Author(s): Helio Henrique Soares Franco, Rachel Muylaert Locks Guimarães, Cássio Antonio Tormena, Maurício Roberto Cherubin, Henrique Sasso Favilla〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Visual Evaluation of Soil Structure (VESS) method has been used frequently to evaluate the structural quality of soils from various parts of the planet, under different edaphoclimatic conditions and cultivation practices. In this context, this paper hypothesised that VESS is sensitive enough to detect differences between structural quality (Sq) scores of VESS from soils with different textural classes, submitted to distinct management and cultivation practices, under contrasting climates. To test this hypothesis, a systematic review and meta-analysis of global scope were conducted, with the objective of compiling and analysing all indexed scientific papers that utilised the method. Exclusion criteria were adopted with the intention of eliminating papers that did not meet the selection criteria for the meta-analysis, however, these papers were used in the systematic review. A sensitivity analysis was performed prior to the meta-analysis in order to evaluate the heterogeneity in the data set, thus increasing the scientific validity of the overall analysis. The results obtained through the systematic review showed that the number of studies using VESS has grown in recent years, not only in temperate regions, but also under diverse soil conditions and cropping systems in subtropical and tropical regions. The meta-analysis showed that temperate soils presented lower Sq scores compared to those observed in tropical and subtropical soils, whereas higher Sq scores were observed in clayey/silty soils compared to sandy soils, regardless of climate zone. Our findings also revealed that Sq scores differences induced by soil management and cropping systems were not detected by the meta-analysis. Thus, the VESS is an on-farm, practical and reliable tool for evaluating the structural quality of soils globally.〈/p〉〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 190〈/p〉 〈p〉Author(s): C.M. Parihar, A.K. Singh, S.L. Jat, A. Ghosh, A. Dey, H.S. Nayak, M.D. Parihar, D.M. Mahala, R.K. Yadav, V. Rai, T. Satayanaryana, M.L. Jat〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Assessment of temperature sensitivity of soil organic carbon (SOC) mineralization from soils of long-term precision conservation agriculture (CA) plots is essential to forecast soil C dynamics. Under CA, varying quantity of inorganic nutrient application had differential impact on SOC. At the same time study of SOC mineralization at different simulated temperatures is important as global climate change affects C-cycle of an agro-ecosystem. To assess the impact of tillage and nutrient management on SOC build-up, a long-term study (five year old) with 3-tillage practices [ZT-zero tillage; PB-permanent beds, & CT-conventional tillage] in main plot and 4-nutrient management strategies [unfertilized, farmer fertilizer practice-FFP, recommended fertilizers-〈em〉Ad-hoc〈/em〉 and a site specific nutrient management-SSNM] in sub-plot in a maize-wheat-mungbean system was chosen. To measure the build-up and thermal sensitivity of SOC, soil samples from 3- depths (0–7.5, 7.5–15 and 15–30 cm) were collected. The kinetics of C-mineralisation was studied through laboratory incubation at 3-temperatures (27, 32 and 37 °C) for 90 days. The PB/ZT and SSNM had significantly higher SOC compared with CT and unfertilized plots, respectively. Although the cumulative C mineralization after 90-days of incubation followed the trend of SOC content among the treatments, while decay rates of SOC mineralization showed somewhat different trend. In all the tillage treatments the percentage of SOC mineralised ranged between 3.3–5.8% at 27 °C, 5.2–8.1% at 32 °C and 7.3–10.9% at 37 °C. At higher temperature, higher SOC decay rates were observed under CT and unfertilized plots compared with PB/ZT and SSNM plots, respectively. The SOC from lower soil depth in CT and unfertilized plots was more temperature sensitive (Q〈sub〉10〈/sub〉 = 4.03 and 4.89, respectively) compared to those under CA-based PB/ZT (Q〈sub〉10〈/sub〉 = 2.63–2.82) and SSNM (Q〈sub〉10〈/sub〉 = 2.15) based balanced nutrition, respectively. The SOC in lower soil depth (7.5–15 and 15–30 cm) is 1.3 and 2.1 times more temperature sensitive respectively than surface soil depth of 0–7.5 cm soil depth. Higher proportion of less labile SOC under CT and unfertilized plots might be the reason for higher temperature sensitivity. In the inevitable and impending global climate change scenario, we might lose a sizeable amount of sequestered C, which is otherwise stable at present ambient temperature.〈/p〉〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 190〈/p〉 〈p〉Author(s): Yang Zhang, Deti Xie, Jiupai Ni, Xibai Zeng〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil nutrient loss is considered to be one of the most important causes of agricultural ecosystem degradation, but a scarcity of comprehensive research has evaluated nutrient losses affected by the reduction in application of specific fertilizers. Here, five phosphate fertilization treatments with conventional phosphate fertilization of 300 kg P〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 ha〈sup〉-1〈/sup〉 yr〈sup〉-1〈/sup〉, 3/4 conventional phosphate fertilization, 1/2 conventional phosphate fertilization, 1/4 conventional phosphate fertilization and zero phosphate fertilization were conducted in a mustard-maize rotation system of the Three Gorges Reservoir (TGR) area. The contents of nitrogen (N), phosphorus (P) and potassium (K) in surface runoff and subsurface leachate and nitrous oxide (N〈sub〉2〈/sub〉O) emission were compared among treatments. Results indicated that reduction of phosphate fertilizer rates from that the current typical rates significantly affected soil nutrient loss in the mustard-maize rotation system in the TGR area, and the effect on surface nutrient loss and N〈sub〉2〈/sub〉O emission were the most significant. The 3/4 and 1/2 conventional phosphate fertilization treatments have no effect on nutrient uptake in mustard and maize, but decreased soil nutrient loss. A Gaussian model fit of data showed that the application of 150–250 kg P〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 ha〈sup〉-1〈/sup〉 yr〈sup〉-1〈/sup〉 was most conducive in improving plant nutrient utilization. Therefore, reducing the phosphate fertilizer application by one-quarter to half of the amount used by conventional fertilization standards in the TGR area is beneficial to decrease soil nutrient loss and restore the ecological degradation of the mustard-maize rotation system.〈/p〉〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 190〈/p〉 〈p〉Author(s): Tomasz Sosulski, Ewa Szara, Magdalena Szymańska, Wojciech Stępień, Beata Rutkowska, Wiesław Szulc〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The paper presents the relts of a study aimed at assessing N〈sub〉2〈/sub〉O-N emissions from arable and forest soils under the climate conditions of Central Poland. Measurements were conducted during the 2012 growing season. N〈sub〉2〈/sub〉O-N emissions from the soil were measured 〈em〉in situ〈/em〉 by infrared spectroscopy using a portable Alpha FTIR spectrometer (Bruker). The measured N〈sub〉2〈/sub〉O-N fluxes showed a high variability over the study period, with fluxes from the arable soil treated with fertilizer (0.08–21.60, median 5.31, mean 7.08 μg N〈sub〉2〈/sub〉O-N m〈sup〉−2〈/sup〉 h〈sup〉-1〈/sup〉) tending to exceed those from the forest soil (0.00–18.78, median 3.35, mean 4.54 μg N〈sub〉2〈/sub〉O-N m〈sup〉−2〈/sup〉 h〈sup〉-1〈/sup〉). N〈sub〉2〈/sub〉O-N fluxes from the arable soil were correlated stronger with the atmospheric temperature and soil moisture than with the soil NO〈sub〉3〈/sub〉--N content. The N〈sub〉2〈/sub〉O-N fluxes from the forest soil were positively correlated with atmospheric temperature only. The relationship between the N〈sub〉2〈/sub〉O-N emission from the arable soil and soil NH〈sub〉4〈/sub〉〈sup〉+〈/sup〉-N content was marked by negative correlation. Based on the measured N〈sub〉2〈/sub〉O-N flux and its relationship with environmental factors (especially the negative correlation between N〈sub〉2〈/sub〉O-N flux and NH〈sub〉4〈/sub〉〈sup〉+〈/sup〉-N content) it can be hypothesized that denitrification is an important source of N〈sub〉2〈/sub〉O-N in arable soils of Central Poland, even when the soil water-filled pore space (WFPS) during the growing season is below 40%. However, in such soil moisture conditions the N〈sub〉2〈/sub〉O-N fluxes from the arable soils are relatively low. The very low soil NO〈sub〉3〈/sub〉--N content throughout almost the entire growing season suggests that nitrification may be the main process producing N〈sub〉2〈/sub〉O-N in the forest soil characterized a low soil pH. The study results indicate that conservation and sustainable management of forests constitute an effective way to mitigate the N〈sub〉2〈/sub〉O-N emissions from the soil. Given the non-zero emission from the forest soils, we postulate a review of the algorithms employed for the approximation of the regional N〈sub〉2〈/sub〉O-N emissions to properly reflect the impact of afforestation on the regional N〈sub〉2〈/sub〉O-N emission.〈/p〉〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 190〈/p〉 〈p〉Author(s): Nkanyiso J. Sithole, Lembe S. Magwaza, Guy R. Thibaud〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil degradation associated with the loss of soil organic carbon (SOC) has been a major concern in sub-Saharan Africa because of the subsequent yield reduction. It is not fully understood how long-term additional C through biomass and N-fertilizers impact on C distribution in soil aggregates and its effects on soil aggregate stability and infiltration in sub-tropical maize monocropping system. The study, therefore, assessed long-term changes in total SOC (TSOC), aggregate-associated C, particulate organic C (POC), aggregate stability and infiltration in the 0–10, 10–20 and 20–30 cm depths under different tillage systems after 13 years of implementation of the trial. The three tillage systems were no-till (NT), rotational tillage (RT) both with permanent residue cover and conventional tillage (CT) with residue removed. N-fertilizer was applied at a rate of 0, 100 and 200 kg/ha. On average TSOC did not vary (〈em〉p〈/em〉 〉 0.05) across the tillage treatments, 27.1 t/ha NT 〈em〉vs〈/em〉 26.0 t/ha RT and 26.6 t/ha CT, but varied with depth where it was stratified in the 0–10 cm depth in NT and RT. Particulate organic C, however, varied significantly (〈em〉p〈/em〉 〈 0.05) across the treatments where it decreased with increase in tillage intensity but only in the 0–10 cm depth. Carbon associated with large aggregates (〉2000 μm) differed marginally (〈em〉p〈/em〉 =  0.085) with tillage treatment with NT having 38.0 t/ha, RT 36.6 t/ha and CT 29.7 t/ha. However, differences (〈em〉p〈/em〉 〈 0.05) were observed in small macroaggregates (250–2000 μm) with NT having 37.8 t/ha, RT 33.5 t/ha and CT 30.4 t/ha in the surface depth. Fertilizer application rate did not seem to affect soil aggregate stability & SOC. The results found a strong effect of residue retention in NT and RT in the soil surface with aggregate stability which, was correlated with the high rate of infiltration rate in these treatments. The results of this study indicate that reduced soil disturbance improves physical protection of SOC, soil structure and infiltration, however, it also indicated that TSOC takes time to improve in maize continuous monocrop system in the studied soil.〈/p〉〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 190〈/p〉 〈p〉Author(s): H.S. Jat, Ashim Datta, M. Choudhary, A.K. Yadav, V. Choudhary, P.C. Sharma, M.K. Gathala, M.L. Jat, A. McDonald〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Intensive tillage based management practices are threatening soil quality and systems sustainability in the rice-wheat belt of Northwest India. Furthermore, it is accentuated with puddling of soil, which disrupts soil aggregates. Conservation agriculture (CA) practices involving zero tillage, crop residue management and suitable crop rotation can serve as better alternative to conventional agriculture for maintaining soil quality. Soil organic carbon is an important determinant of soil quality, playing critical role in food production, mitigation and adaptation to climate change as well as performs many ecosystem functions. To understand the turnover of soil carbon in different forms (Total organic carbon-TOC; aggregate associated carbon-AAC; particulate organic carbon- POC), soil aggregation and crop productivity with different management practices, one conventional agriculture based scenario and three CA based crop management scenarios namely conventional rice-wheat system (Sc1), partial CA based rice-wheat-mungbean system (Sc2), full CA-based rice-wheat-mungbean system (Sc3) and maize-wheat-mungbean system (Sc4) were evaluated. TOC was increased by 71%, 68% and 25% after 4 years of the experiment and 75%, 80% and 38% after 6 years of the experiment in Sc4, Sc3 and Sc2, respectively, over Sc1 at 0–15 cm soil depth. After 4 years of the experiment, 38.5% and 5.0% and after 6 years 50.8% and 24.4% improvement in total water stable aggregates at 0–15 and 15–30 cm soil depth, respectively was observed in CA-based scenarios over Sc1. Higher aggregate indices were associated with Sc3 at 0–15 cm soil depth than others. Among the size classes of aggregates, highest aggregate associated C (8.94 g kg〈sup〉−1〈/sup〉) was retained in the 1-0.5 mm size class under CA-based scenarios. After 6 years, higher POC was associated with Sc4 (116%). CA-based rice/maize system (Sc3 and Sc4) showed higher productivity than Sc1. Therefore, CA could be a potential management practice in rice-wheat cropping system of Northwest India to improve the soil carbon pools through maintaining soil aggregation and productivity.〈/p〉〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 190〈/p〉 〈p〉Author(s): M.H.J.P. Gunarathna, Kazuhito Sakai, Tamotsu Nakandakari, Kazuro Momii, M.K.N. Kumari, M.G.T.S. Amarasekara〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Knowledge of the hydraulic properties of soil is a vital factor in evaluating and managing environmental and agricultural problems. The expense and difficulty of measurements have prompted the development of other approaches to estimate soil hydraulic properties. Pedotransfer functions (PTFs) are predictive functions used to estimate soil properties on the basis of easily measurable soil parameters. Although PTFs are in use for most temperate regions, few attempts have been made to develop them for locations in the tropics. This study aimed to establish suitable PTFs for tropical soils of Sri Lanka to estimate soil hydraulic properties (field capacity and permanent wilting point) by a multiple linear regression method from inputs consisting of different combinations of four easily measured parameters: sand content; sand, silt, and clay content; bulk density; and organic carbon concentration. This analysis used the open-source data mining software in the Waikato Environment for Knowledge Analysis. We found that all the PTFs developed using different input levels showed similar performances. Our functional evaluation showed that the output of the PTFs performed essentially as well as measured data for estimating available water content and generating irrigation schedules for the selected localities. Hence, even using sand percentage alone, volumetric water contents at –10, –33, and −1500 kPa can be successfully estimated using PTFs developed for Sri Lankan soil conditions.〈/p〉〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 192〈/p〉 〈p〉Author(s): Danilo dos Santos Rheinheimer, Mayara Regina Fornari, Marília Camotti Bastos, Gracieli Fernandes, Maria Alice Santanna, Ademir Calegari, Lutécia Beatriz dos Santos Canalli, Laurent Caner, Jérôme Labanowski, Tales Tiecher〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The no-tillage system combining winter cover crops and crop rotation may increase the efficiency use of soil P and phosphate fertilizer. The objective of this study was to evaluate the effect of three decades of different soil management systems and winter cover crops on the fractions of P in a clayey Oxisol of Paraná State, Brazil. The bi-factorial experiment with three replicates was established in 1986. The main plots consisted of seven winter cover crops. In the subplots, two tillage systems were used: no-tillage and conventional tillage. The soil was sampled in the 0–10 cm soil layer in each plot in the post-harvest of the corn (March 2015), the flowering of the winter cover crops (September 2015) and at soybean flowering (February 2016). Samples from a native forest adjacent to the experimental area were also taken for comparison. The different pools of P were evaluated. Results indicated that after 30 years of no-till with phosphate fertilizers addition, the amount of P organic pools and type of P organic compound were very similar to those observed in the natural biome. The no-tillage guaranteed higher inorganic and organic P, both rapid and moderately available, in comparison to the conventional tillage system. However, in the conventional tillage (40 years − 80 plows + 160 harrows), despite the addition of 3 Mg ha〈sup〉−1〈/sup〉 of P〈sub〉2〈/sub〉O〈sub〉5〈/sub〉, the available and moderately labile P content in soil surface were very similar to soil under natural forest. In the natural biome, the amount of P stored in soil microbial biomass was stable in the time showing a homeostatic equilibrium. Nevertheless, in cultivated soil and fertilized with inorganic phosphate, there was a synchronism between plant demand and storage in soil microbial biomass. Except for P stored in soil microbial biomass, the other P pools, regardless its nature (organic or inorganic) or degree of bioavailability, had despicable or absent effect of winter cover plants, compared to winter fallow.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): F.J. Moral, F.J. Rebollo, C. Campillo, J.M. Serrano〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The first stage to implement site-specific crop management (SSCM) within an agricultural field consists in determining subfields of similar production potential, that is, management zones (MZ). Different approaches have been proposed to delineate MZ, but sometimes results are inaccurate and unsatisfactory. In this study, the formulation of the Rasch measurement model, as an objective method which synthesizes data with different units into a uniform analytical framework, is considered to calculate measures of production potential at some locations of an olive orchard. Later, they can be used to delimit MZ.〈/p〉 〈p〉With the aim of illustrating this approach, nine soil properties (soil apparent electrical conductivity, clay, sand, and silt content, organic matter, total nitrogen, available phosphorous and potassium, and cation exchange capacity) measured from soil samples taken at 40 locations in a field were considered. The main results, after applying the Rasch model, were a ranking of all locations according to the soil production potential and another one in which the influence on the production potential of each individual soil property is shown. Moreover, those soil samples or properties which have any anomaly where highlighted; this information can be necessary to conduct site-specific treatments, leading to a more cost-effective and sustainable field management. Additionally, estimates using geostatistical algorithms were utilised to map soil production potential and to delineate with a rational basis the MZ in the field.〈/p〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Jie Wang, Guobin Liu, Chao Zhang, Guoliang Wang, Linchuan Fang, Yongxing Cui〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Microorganisms play critical roles in soil biogeochemical processes and the establishment of vegetation communities. However, their long-term successional patterns and associations with environmental factors are not well understood, especially in semiarid areas where plant community composition and species diversity change rapidly. We investigated changes in soil (〈em〉Cambisol〈/em〉) microbial communities across a chronosequence of abandoned farmland comprising six successional stages (0, 11, 35, 60, 100, and 150-years) in the semiarid Loess Plateau of China. We aimed to reveal the long-term patterns and succession rates of microbial communities, and to reveal the driving forces. Bacterial and fungal communities were characterized by sequencing bacterial 16S ribosomal RNA genes and fungal internal transcribed spacers (ITS), respectively. Temporal turnover of microbial succession was investigated using the slope (〈em〉w〈/em〉 value) of linear regression of log-transformed microbial community similarity over time. Succession rate of fungi was approximately three times higher (〈em〉w〈/em〉 = 0.1477, 〈em〉P〈/em〉 〈 0.0001) than that of bacteria (〈em〉w〈/em〉 = 0.0549, 〈em〉P〈/em〉 〈 0.0001). Bacterial succession was affected by changes in soil NH〈sub〉4〈/sub〉〈sup〉+〈/sup〉-N, total N, organic C, water content, bulk density, and pH, whereas fungi were more susceptible to changes in NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉-N, available phosphorus, and C:N ratio. Bacterial communities transitioned from slow-growing oligotrophic groups (〈em〉Gemmatimonadetes, Chloroflexi〈/em〉) to fast-growing copiotrophic groups (〈em〉Alpha〈/em〉- and 〈em〉Betaproteobacteria〈/em〉). 〈em〉Basidiomycota〈/em〉 showed the highest temporal turnover (〈em〉w〈/em〉 = 0.2000, 〈em〉P〈/em〉 〈 0.0001), followed by 〈em〉Armatimonadetes〈/em〉, 〈em〉Firmicutes〈/em〉, 〈em〉Verrucomicrobia〈/em〉, 〈em〉Chloroflexi〈/em〉, and 〈em〉Proteobacteria〈/em〉. These results provide new insights into microbial community dynamics during long-term secondary succession, and enhance our understanding of associations between soil factors and microbes in semiarid ecosystems.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): José Ferreira Lustosa Filho, Cristiane Francisca Barbosa, Jefferson Santana da Silva Carneiro, Leônidas Carrijo Azevedo Melo〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Developing slow-release phosphate sources more synchronized with the crop cycle is needed to increase phosphorus (P) use efficiency in weathered tropical soils. We hypothesized that impregnation of biomass with phosphate and magnesium prior to biochar production will generate slow-release P fertilizer and increase P use efficiency by plants. In this study, triple superphosphate (TSP) or phosphoric acid (H〈sub〉3〈/sub〉PO〈sub〉4〈/sub〉) were mixed with magnesium oxide (MgO) and poultry litter (PL) to produce slow-release P biochar-based fertilizers (BBFs). The P fractions of the BBFs soluble in water, citric acid and neutral ammonium citrate + water were analyzed. Phosphorus diffusion in soil was determined using a visualization technique over time and chemical analyses, and the agronomic efficiency of the BBFs was compared with soluble fertilizer (TSP) in both granular and powder form for maize grown in an Oxisol under greenhouse conditions. Results showed that BBFs strongly decreased water-soluble P, which caused a slow-release of P in soil as demonstrated by diffusion visualization technique. When applied as powder mixed through the soil, BBFs improved soil pH and Mg and were able to provide P to plants similarly to TSP. The granular form of PLB-H〈sub〉3〈/sub〉PO〈sub〉4〈/sub〉-MgO was equivalent to TSP for P release during early growth of maize and preserved higher amounts of P in the granule, which can be used for plants in future harvests. Pyrolysis of biomass with phosphate and magnesium can be an option to enhance P use efficiency from fertilizers, especially for on high P-fixing soils.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0167198718306718-ga1.jpg" width="265" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 191〈/p〉 〈p〉Author(s): M.A. Kader, K. Nakamura, M. Senge, M.A. Mojid, S. Kawashima〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Numerical simulations for predicting soil-water and heat-flow regimes beneath mulched soils are important to increase the opportunity for efficient use of mulching in agriculture. This study simulated water and heat flows by HYDRUS-1D model under rice-straw mulching and bare soil treatments for rain-fed soybean (〈em〉Glycine max〈/em〉) cultivation at Gifu Prefecture in central Japan. Soil hydraulic and thermal parameters with the straw mulching were optimized by adding a hypothetical 3-cm straw layer. The optimized parameters were validated with field-measured soil-moisture and temperature regimes of two consecutive soybean-growing seasons of 2015 and 2016. HYDRUS-1D model performed fairly well in simulating heat and water movements at 5, 15 and 25 cm soil depths under the two treatments. The model simulated soil moisture and temperature with small Root-Mean Square Error (RMSE): 0.016–0.044 cm〈sup〉3〈/sup〉  cm〈sup〉–3〈/sup〉 for soil moisture and 0.94–1.63 °C for soil temperature. The simulation results revealed that straw mulching increased soil moisture but reduced soil temperature at the three soil depths compared to the bare soil. The moisture content of the additional straw layer (3 cm) and heat flow through it showed a decreasing pattern compared to the soil layers. The straw mulching contributed 16–96% vapor to the total water flow and stored/released 0.0322 to 0.0295 MJ m〈sup〉–2〈/sup〉 heat per day at 0–3 cm straw layer. Water balance in the soybean field revealed that the straw layer enhanced rain water infiltration by limiting evaporation from the soil surface. The simulation results can be useful for better management of soil hydro-thermal regimes under straw-mulched fields in dryland cultivations.〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 191〈/p〉 〈p〉Author(s): Miguel A. Gabarron-Galeote, Jacqueline A. Hannam, Thomas Mayr, Patrick J. Jarvis〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Sugar beet in the UK is harvested in autumn and winter, when soil moisture is usually close to field capacity. This, together with the heavy machinery used can lead to serious environmental problems such as topsoil disturbance, subsoil compaction and soil erosion. BEETSOIL is a decision support tool (DST) developed to help plan the sugar beet harvest campaign by assessing if soil conditions are suitable for harvest whilst minimising the occurrence of soil damage. The core of BEETSOIL is a soil water balance model that, using a rainfall source selected by the user, predicts soil water content in a determined prediction window. The resulting soil water content is used to predict soil trafficability, wheel sinkage, soil stickiness and soil loss due to harvest on a daily basis. The soil water balance module was validated with measured soil water content at three field sites with contrasting clayey, silty and sandy textures and showed RMSE of 0.91%, 0.96% and 0.52%, respectively. The sensitivity of the trafficability modules of BEETSOIL were tested using several scenarios using different initial soil water contents at the start of the harvest campaign combined with rainfall amounts that simulate wet, median and dry conditions during the harvest period. Analysis of the scenarios showed the trafficability module was very sensitive to changes in texture, initial soil water content of the simulation and rainfall. This information can be used to assess the suitability of new sugar beet growing areas, where the proportion of time during which fields can be trafficked by vehicles (harvested effectively) can be predicted under different scenarios and therefore give an indication of any consistent harvest difficulties. The model outputs of sinkage, trafficability and soil loss by harvest have yet to be validated, but the first outputs provide indications of how the DST can be used across the whole growing area to schedule harvest operations to target areas that can be harvested most effectively.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Mehmet Zahid Malasli, Ahmet Celik〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Disc angles which play an important role on horizontal (draft), side and vertical forces are divided into two as the disc and tilt angle. Five disc angles (0, 5, 10, 15 and 20°), five tilt angles (0, 2.5, 5, 7.5 and 10°), three vertical disc loads of 50 kg, 100 kg and 150 kg and no-residue, wheat and corn residue conditions were taken into account in this study which was conducted under soil bin conditions. The angles of the disc opener were easily changed by using a mechanism designed and manufactured for this purpose. According to the obtained results, the increase in disc angle led to an increase of the vertical and draft forces that affect the disc and minimum values at 0° disc angle and maximum values at 20° disc angle were obtained. The vertical forces acting on the disc according to disc angle varied between 321.5 N and 373.4 N while the draft forces were between 92.2 N and 131.3 N. As the tilt angle increased, the draft forces decreased, and these values were measured between 122.7 N and 103.7 N. The vertical forces ranged from 335.1 N to 360.6 N. It has been determined that the 7.5 and 10° tilt angles generally give better results. The increase in the vertical load applied to the disc enabled penetration into the soil, while at the same time an increase incurred in the vertical, draft and side forces acting on the furrow opener. In addition, the vertical, draft and side forces acting on the disc type opener and the data of cross-sectional area of the furrows opened were used to calculate specific vertical, specific draft and specific side forces Results indicate that an increase in disc angle decreased specific draft, side and vertical forces. An increase of the tilt angle caused the specific vertical, draft and side forces to increase.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): G.A. Miller, R.M. Rees, B.S. Griffiths, B.C. Ball, J.M. Cloy〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The rate of change in the relative size of SOC pools (sensitivity) due to land management may vary depending on their level of chemical and/or physical protection from decomposition, but has rarely been directly measured. The availability of archived (1975) soils from an abandoned long term tillage treatment experiment provided a unique opportunity to assess the sensitivity of SOC pools with different levels of stability to uniform land management after divergent tillage treatments. There were four initial treatments (1968–1991): 1) deep plough then no till, 2) shallow plough, 3) reduced till then rotary cultivation and 4) no till. The treatments were followed by uniform long-term grassland management (17 years) and subsequent short-term arable (two years). The sensitivity of SOC to land management was assessed by fractionation and direct comparison of archived soils and soils sampled in 2014 from this site. Both reductions and increases in SOC stocks were observed over time in comparable treatments but the overall effect was a trend towards an equilibration of SOC stocks across all plots. The labile fractions (particulate and dissolved organic matter) were sensitive to land management regardless of initial tillage treatment, but were more sensitive in the reduced till + rotary cultivation and no till treatments (2.3–5.3 times more sensitive than the whole soil) than the deep plough + no till and shallow plough treatments (1.12.2 times more sensitive than the whole soil). The chemically resistant fraction of the soils was surprisingly sensitive to land management (0.9–1.3 times more sensitive than the whole soil). This study shows that the degree of sensitivity of SOC fractions to land management can vary significantly depending on previous tillage management practices.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Chris Bluett, Jeff N. Tullberg, John E. McPhee, Diogenes L. Antille〈/p〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Haiqing Chen, Qiong Liang, Yuanshi Gong, Yakov Kuzyakov, Mingsheng Fan, Alain F. Plante〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil organic matter (SOM) concentration and enzyme activity are important biochemical indicators of soil health for assessing the sustainability of agricultural management practices. However, little is known about the long-term effects of tillage and crop residue management on SOM and enzyme activities in soil particle-size fractions on the Loess Plateau of Northern China. The objective of this study was to investigate the effects of 11 years of combined tillage and crop residue management treatments on soil organic carbon (SOC), total nitrogen (TN) concentrations and enzyme activities in bulk soil and particle-size fractions from a rainfed wheat (〈em〉Triticum aestivum〈/em〉 L.) monoculture system in this region. We hypothesized that reduced tillage and increased residue retention would increase SOC, TN and enzyme activities in both bulk soil and particle-size fractions, and that enzyme activity would serve as a more sensitive indicator of soil health in response to management. Compared with conventional tillage and residue removal (CTRR), reduced tillage and stubble mulch residue retention (RTSM) increased bulk soil activities of most enzymes (sulfatase +68%, invertase +62%, β-glucosidase +58%, dehydrogenase +46%). These increases were greater than the relative increases in total SOC (34%) and TN (33%) concentrations, supporting our hypothesis of a stronger response in microbial activity to management than total element stocks. The RTSM treatment also increased SOC and TN concentrations, as well as β-glucosidase, acid phosphatase and urease activities in all particle-size fractions (2000-250, 250-53, 53-2 and 〈 2 μm) compared with the CTRR treatment. Both β-glucosidase and acid phosphatase showed a general decrease from coarse- to fine-sized fractions, and resembled the distribution of SOC and TN concentrations in particle-size fractions. Conversely, urease activity was greater in sand and clay fractions, which was decoupled from SOC and TN distributions. Our results indicate that biological indicators of soil health were more sensitive than C and N stocks to cumulative long-term changes in tillage and residue management.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Jinsen Zheng, Ying Qu, Method M. Kilasara, William N. Mmari, Shinya Funakawa〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nitrate (NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉) leaching from agriculture is a growing environmental concern, but little attention has been given to the cropping systems in sub-Saharan Africa, where efforts are underway to increase fertilizer (especially nitrogen, N) use to secure food production. During 2015–2017, we monitored NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉 leaching from the critical root zone of maize in the tropical highlands of Tanzania using repacked soil monolith lysimeters. Four urea-N rates (0–150 kg N ha〈sup〉−1〈/sup〉) and in combination with maize straw (∼2 Mg C ha〈sup〉−1〈/sup〉; C:N ≥ 60) were evaluated in two soil types (sandy Alfisols and clayey Andisols). The soil rewetting process, particularly at the onset of the rainy season and following N applications, was a critical driver of NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉 flux. Nitrate leaching increased exponentially with increasing N rates, yet inter-annual variation was observed. Relating cumulative NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉 flux to maize yield under increasing N rates revealed a tipping point—occurrence depending on season—above which yield increments were accompanied by substantial NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉 leaching. Such a tipping point occurred at the N rate of 62 and 50 kg N ha〈sup〉−1〈/sup〉 at the sandy and clayey site, respectively, in the second season. Straw incorporation induced net N immobilization in the early growing season, and reduced NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉 leaching by 3.3–6.3 kg N ha〈sup〉−1〈/sup〉, but no effect was observed on the cumulative NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉 fluxes or maize yields. The NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉 leaching reductions (equivalent to 1.2–2.7 kg N Mg〈sup〉−1〈/sup〉 C) were far below the net N immobilization potential of the incorporated straw (18.0–38.1 kg N Mg〈sup〉−1〈/sup〉 C; for C:N ratios of 60–206). This was likely caused by large pieces of straw (∼0.15 m) used in the field, which reduced the surface area exposed to soil and microbes; consequently, only limited N in the decomposition microsites could be immobilized. Our results showed the potential to enhance maize yield without inducing substantial N leaching by adopting the proper N rate in the tropical highlands of Tanzania, and highlighted that temporary immobilization of leachable N by using large pieces of straw in the field was inefficient for the improvement of N synchrony and benefits to yield.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Fengling Ren, Nan Sun, Meng Xu, Xubo Zhang, Lianhai Wu, Minggang Xu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil microbial biomass carbon (SMBC) and nitrogen (SMBN) are important indices of soil bio-fertility. While intensively managed cropping systems can reduce microbial biomass, application of manure is a potential way to rebuilt microbial biomass and improve soil functions. However, the responses of SMBC and SMBN to manure application relative to mineral fertilizers (NPK) in Chinese cropping systems remains unclear. We conducted a meta-analysis based on 103 peer-reviewed publications with 1448 paired observations to identify the degree to which climate types, soil properties and agricultural managements regulate the responses of microbial biomass to manure amendment relative to NPK. The results indicated that manure application increased SMBC, SMBN, SMBC/soil organic carbon (SOC) and SMBN/soil total nitrogen (TN) by 40%, 55%, 16% and 21%, respectively, across all the observations compared to NPK. SMBC/SMBN under manure amendment (6.58 in average) was lower than that in NPK (7.86 in average). Manure-related factors, e.g. manure types, duration of application, manure-C and N input rates, were the strongest regulators of the response of microbial biomass. Soil properties and climates also contributed to considerable degrees of variation in microbial biomass response based on variance partitioning analysis (VPA). Results of the random forest (RF) models showed that manure type, application rate (manure-C and N input) as well as soil initial properties (SOC, TN and clay contents) were likely the predominant factors controlling the response of microbial biomass to manure application. Our study indicates that manure application can be an effective way to restore the loss of microbial biomass due to intensive application of NPK, yet variations in response are determined by specific manure type, application rate, as well as local conditions of climate and inherent soil properties.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Fig. Relative importance of independent variables for controlling SMBC (a), SMBN (c) changes after manure application as determined using random forests (RF) models and the performance of random forests models for detecting controlling factors of SMBC (b), SMBN (d) change in the croplands in China.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0167198719300133-ga1.jpg" width="269" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 191〈/p〉 〈p〉Author(s): Zhiyuan Yao, Dabin Zhang, Na Liu, Pengwei Yao, Na Zhao, Yangyang Li, Suiqi Zhang, Bingnian Zhai, Donglin Huang, Zhaohui Wang, Weidong Cao, Sina Adl, Yajun Gao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Estimating the dynamics and future sequestration potential of soil organic carbon stocks (SOCS) and total nitrogen stocks (TNS) is useful to determine whether cropping systems can promote sustainable production in terms of improving soil fertility. The Rothamsted Carbon (RothC) model and the correlations between SOCS and TNS were used to estimate the future SOCS and TNS of green manure-based wheat production systems on the Loess Plateau of China. The field study was a split-plot design with 4 main treatments (Huai bean, soybean and mung bean grown as green manure in summer, with a fallow treatment as the control) and 4 subtreatments (synthetic N rates of 0, 108, 135 and 162 kg ha〈sup〉−1〈/sup〉 applied at wheat sowing). Leguminous green manure (LGM) treatments increased the amount of carbon and nitrogen returned to the field by 67–91% and 74–125%, respectively, compared with the fallow treatment (〈em〉P〈/em〉 〈 0.05). These treatments also increased SOCS by 15–23% and TNS by 12–22% (〈em〉P〈/em〉 〈 0.05) after 8 years in comparison with the fallow treatment. Coupling of the RothC model and the correlations between SOCS and TNS of the 3 LGM treatments generated acceptable simulations for the dynamics of SOCS and TNS. The projected SOCS for LGM and fallow treatments at the new equilibrium are 37.67–47.29 and 13.97–17.58 Mg ha〈sup〉−1〈/sup〉, respectively. The corresponding TNS for LGM treatments are 5.42–6.79 Mg ha〈sup〉−1〈/sup〉. The projection also indicates that under the LGM treatments, the SOCS and TNS at the new equilibrium will be 107% and 158% higher, respectively, than the baseline level. In conclusion, growing LGM to replace summer fallow would be a useful alternative to improve soil fertility and promote sustainable crop production.〈/p〉〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 190〈/p〉 〈p〉Author(s): S.L. Jat, C.M. Parihar, A. Dey, H.S. Nayak, A. Ghosh, N. Parihar, A.K. Goswami, A.K. Singh〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the scenario of global climate change, the enhancement and stabilization of soil organic carbon holds prime importance. In this context, conservation agriculture (CA) based practices 〈em〉i.e.,〈/em〉 diversified cropping systems and permanent bed (PB) holds great potential. In this article, we have compared the dynamics of soil organic carbon under mustard and wheat based systems [MMuMb, maize-mustard-mungbean and MWMb, maize-wheat-mungbean)] planted on PB, with and without residue (PB + R and PB - R) along with four nitrogen (N) management options [Un-fertilized, N through prilled urea (PU), N through sulphur coated urea (SCU), and N through neem coated urea (NCU)]. After 5-years of experimentation, to assess the medium-term impact of full CA (PB + R) in comparison to partial CA (PB-R) on SOC dynamics under mustard and wheat based systems with diverse N sources, we had conducted an incubation study at three temperature levels (27, 32 and 37 °C) in a sandy loam soil (Typic Haplustept) of north-western Indo- Gangetic Plains (IGP) of India. Wheat-based cropping system (MWMb) resulted in higher values of less labile, non-labile as well as total SOC, as compared with mustard-based system (MMuMb). On the other hand, MMuMb registered higher amount of very labile and labile SOC, with enhanced decay rate. The cumulative C mineralization (Ct) was 11–17% higher under MMuMb compared with MWMb, from all the soil depths at 27 °C. Retention of crop residue in PB increased total SOC by 11.5 to 19.5% compared with PB-R, across the soil depths. The Ct were significantly higher under full CA plots with lower decay rate (Kc), as compared to plots under partial CA. Application of N fertilizers registered a significant hike in total SOC compared to un-fertilized control plots. At the same time, the coated N sources 〈em〉i.e.,〈/em〉 SCU and NCU failed to cause any significant improvements in total SOC as compared with uncoated PU plots. On the other hand, coated urea treated plots registered significantly higher C mineralization compared with uncoated PU plots. Between the two coated urea products, the NCU application registered significantly higher C mineralization compared with SCU across the sampling events and temperature regimes from all the soils layers. Cropping system or residue addition/removal did not affect temperature sensitivity of SOC mineralisation. At the same time, addition of N-fertilizers, irrespective of sources lowered the Q〈sub〉10〈/sub〉 compared with no-N fertilization.〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 191〈/p〉 〈p〉Author(s): Margita Hefner, Rodrigo Labouriau, Michael Nørremark, Hanne Lakkenborg Kristensen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Increased farm machinery weight in agricultural production results in soil compaction. Controlled traffic farming (CTF) restricts traffic to permanent lanes, thereby creating traffic free beds for crop production. Field experiments were conducted at two organic vegetable farms in Denmark, on a sandy loam (2013–2016) and on coarse sand (2013–2015) to investigate CTF effects compared with random traffic farming (RTF) on vegetable yield, root growth, and soil mineral nitrogen (N). Root growth was measured using minirhizotrons. White cabbage, potato, and beetroot yield increased by 27%, 70% and 42%, respectively, in CTF compared with RTF in 2015 and winter squash indicated a yield increase of 43% on sandy loam in 2016. White cabbage (2015) and potato, beetroot and winter squash (2016) grew 2–25 times more roots and beetroot grew deeper roots under CTF compared with RTF on sandy loam in 2016. On coarse sandy soil, beetroot root frequency was 1.4 times greater under CTF than under RTF and beetroot roots grew deeper than 1.5 m under both treatments in 2015. Soil mineral N and potential net N mineralization were equal between treatments or higher in CTF by 2–41 kg ha〈sup〉−1〈/sup〉 and 11 mg kg〈sup〉−1〈/sup〉 35 days〈sup〉−1〈/sup〉, respectively, indicating N supply was maintained or increased in this system. Despite the variability in crop and root growth responses to traffic between years and crops, the effects were always equal or positive for CTF following treatment implementation. Therefore, our results encourage the use of CTF for organic vegetable production under temperate conditions.〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 191〈/p〉 〈p〉Author(s): Ganesh Upadhyay, Hifjur Raheman〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Predicting draft requirements of tillage implements is essential from the viewpoint of proper tractor-implement matching and machinery design. It was hypothesized that draft requirement of offset disc harrow (ODH), a widely used tillage implement depends mainly on four major soil and working parameters, i.e. soil cone index (CI), forward speed, working depth and front gang angle (FGA), which could be used to develop a reasonable regression model for estimating its specific draft. To test this hypothesis, investigations were carried out on the draft requirement of ODH in an indoor soil bin available at Indian Institute of Technology, Kharagpur (22°19′ N, 87°19′ E), India during the months of November 2016 to May 2017. The soil available in the soil bin was acid lateritic sandy clay loam and taxonomically grouped under order Alfisol (Oxyaquic haplustalf). The experimental design was completely randomized with draft measured using S-type load cell (2-tonne capacity) at four levels each of FGA and forward speed, three levels each of working depth and soil CI using a 3 × 3 ODH (i.e. 3 discs in each of the two gangs) with the objective to acquire data on the draft force requirement of ODH at various soil and working parameters. The forward speed, working depth, and soil CI were measured with the help of a magnetic-type proximity switch, rotary potentiometer, and hydraulic cone penetrometer, respectively and were found to have a significant effect (p ≤ 0.01) on the draft with CI having highest influence followed by working depth, speed, and FGA. Multiple regression analysis was carried out to develop a model for estimating specific draft for ODH. The efficiency of specific draft model, was assessed by various performance indices such as mean error (ME), value account for (VAF), root mean square error (RMSE), coefficient of determination (R〈sup〉2〈/sup〉), and mean absolute percentage error (MAPE) and their values were found to be -3.22, 92.77%, 4.82, 0.90 and 14.75, respectively. A major advantage of the developed specific draft model compared to other researchers’ model is the inclusion of all parameters that affect draft especially FGA and CI which would increase its applicability. A good general agreement between measured and estimated specific draft was found with the data obtained from the soil bin with an average absolute variation (AAV) of 10.76%. Verification of the model was also carried out by comparing its outputs with the model outputs of previous researchers to check its applicability for other soil types and working conditions, and the results were found to be fairly good (Al-Janobi and Al-Suhaibani, 1998 (R〈sup〉2〈/sup〉 = 0.87, AAV = 14.33%), Kheiralla et al., 2004 (R〈sup〉2〈/sup〉 = 0.93, AAV = 11.95%), and Roul, 2014 (R〈sup〉2〈/sup〉 = 0.94, AAV = 23.05%) except the ASABE draft model (R〈sup〉2〈/sup〉 = 0.66, AAV = 50.18%). Therefore, the developed model in this research could be used to predict draft requirements of ODH’s with reasonable accuracy.〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 191〈/p〉 〈p〉Author(s): Tingmiao Huang, Qiannan Huang, Xu She, Xiaolong Ma, Ming Huang, Hanbing Cao, Gang He, Jinshan Liu, Dongli Liang, Sukhdev S. Malhi, Zhaohui Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉It is useful to understand soil nutrients responsible for grain zinc (Zn) variation of winter wheat (〈em〉Triticum aestivum〈/em〉 L.) in different cropping regions, in order to adopt appropriate soil management measures to improve grain Zn nutrition and alleviate human Zn malnutrition. A total of 599 wheat plant and corresponding soil samples were collected from farmers’ fields in three typical wheat cropping regions of China in 2015 and 2016, to determine the dominant soil nutrients related to high grain Zn concentration. Obtained results showed that a large variation in grain Zn existed within different regions, with 8%, 9% and 16% of grain samples reaching the recommended level of 40 mg kg〈sup〉−1〈/sup〉 in the single wheat, wheat-maize and rice-wheat regions, respectively. In the single wheat region, grain Zn was positively correlated with soil available potassium (K) and Zn, and negatively correlated with available iron (Fe) (〈em〉P〈/em〉 〈  0.001), with the available K being 164 and 117 mg kg〈sup〉−1〈/sup〉, Zn 0.64 and 0.46 mg kg〈sup〉−1〈/sup〉, and Fe 3.3 and 5.2 mg kg〈sup〉−1〈/sup〉 for the high and low Zn groups, respectively. In the wheat-maize region, grain Zn was positively correlated with soil available Zn, while negatively correlated with available phosphorus (P) (〈em〉P〈/em〉 〈  0.001), with the available Zn being 1.7 and 1.3 mg kg〈sup〉−1〈/sup〉, and P 24 and 25 mg kg〈sup〉−1〈/sup〉 for the high and low Zn groups, respectively. In the rice-wheat region, grain Zn was positively correlated with soil ammonium nitrogen (Amon-N) and available Zn (〈em〉P〈/em〉 〈  0.001), with Amon-N being 7.2 and 4.6 mg kg〈sup〉−1〈/sup〉, and available Zn 1.9 and 1.2 mg kg〈sup〉−1〈/sup〉 for the high and low Zn groups, respectively. Therefore, it is possible to produce wheat with grain Zn higher than 40 mg kg〈sup〉−1〈/sup〉 in farmers’ fields, and apart from available Zn, soil available K and Fe in the single wheat region, available P in the wheat-maize region, and Amon-N in the rice-wheat region should also be considered for the purpose of grain Zn improvement.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0167198718306743-ga1.jpg" width="378" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 191〈/p〉 〈p〉Author(s): Shufang Guo, Limei Zhai, Jian Liu, Hongbin Liu, Anqing Chen, Hongyuan Wang, Shuxia Wu, Qiuliang Lei〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Losses of nutrients, water and soil from sloping farmlands have a large potential to contribute to water eutrophication and land degradation. However, few long-term and multi-site measurements are available to assess the magnitude of effects of cross-ridge tillage on surface runoff and nitrogen (N) and phosphorus (P) losses from sloping farmlands. Field experiments were conducted under natural rainfall conditions for six to seven years across four experimental sites in southern China. Each site-year experiment consisted of three management practices: downslope ridge without fertilizer as control (CK), downslope tillage with fertilizer (DF), and cross-ridge with fertilizer (CF). Results indicated that compared to the downslope tillage practice, cross-ridge tillage reduced the average annual runoff by 6.11% to 64.2%. Compared with DF, CF significantly decreased total N (TN) and total P (TP) losses by 11.3% to 69.7% and 15.9%- to 63.5%, respectively (〈em〉P〈/em〉 〈 0.05). The decreases in TN and TP losses were significantly associated with sediment yield reduced by cross-ridge, which significantly reduced both particulate N and particulate P losses. While TN loss in CF was dominated by total dissolved N (62.4%), particulate P accounted for 68.4% of TP in runoff. Across all tillage practices, N and P losses increased at higher soil N and P contents, indicating the necessity of adopting crop and nutrient management practices to reduce soil nutrient levels and thus nutrient losses from sloping farmlands. Despite regional and temporal variabilities, cross-ridge tillage consistently reduced surface runoff, sediment yield, and N and P losses compared with downslope tillage. In conclusion, cross-ridge tillage is an effective conservation measure to reduce soil erosion and nutrient losses from sloping farmland in China’s hilly regions.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Alireza Amirian-Chakan, Budiman Minasny, Ruhollah Taghizadeh-Mehrjardi, Rokhsar Akbarifazli, Zahra Darvishpasand, Saheb Khordehbin〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil texture is the most well-known composition in soil science. When separate components of the texture (sand, silt, and clay) are predicted independently in digital soil mapping (DSM), there is no guarantee that the separate estimates will sum to 100%. Log-ratio transformations before DSM modelling are alternatives to guarantee a constant sum of the estimates. Little is known about the effect of non-summing to 100% and transformations of particle-size fractions (PSFs) when DSM products were used to predict soil functional properties using pedotransfer functions (PTFs). Therefore, this study was conducted to investigate the effect of different soil texture modelling methods on the estimation of available soil water capacity (AWC) and the total amount of irrigation water (TIW) required for wheat production on a 4600 ha area in Khuzestan province, southwestern Iran. Specifically, this study aimed i) to assess the performance of random forest models (RF) to predict untransformed (UT) and transformed PSFs using environmental covariates; ii) to study the effects of three widely used log-ratio transformations including additive, centroid and isometric log-ratio transformations (alr, clr, and ilr respectively) on the estimations of AWC and TIW. A total of 150 soil samples were collected from the surface layers (0–30 cm) based on the conditioned Latin hypercube sampling (cLHS) procedure. Results indicated that, in terms of root mean square error (RMSE), RF provided similar accuracies in predicting PSFs for both untransformed and transformed data. However, transformation resulted in biased estimates. In addition, RF prediction based on untransformed data resulted in more correctly soil texture classes allocation when compared to transformed data. The spatial distribution of the sum of the predicted untransformed fractions indicated only small parts of the area conformed to the 100% sum. Almost the same accuracies for estimates of AWC were obtained when both untransformed and transformed predicted texture components were used as the inputs to PTFs. Data transformation can result in biased estimates of AWC. The findings indicated no significant difference between transformation methods in predicting AWC and TIW. The general patterns of the spatial distribution of the predicted AWCs across the whole area were the same for transformed and untransformed data (except for clr transformation).〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Catherine Mathenge, Moses Thuita, Cargele Masso, Joseph Gweyi-Onyango, Bernard Vanlauwe〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Rhizobia inoculation can increase soybean yield, but its performance is influenced by among others soybean genotype, rhizobia strains, environment, and crop management. The objective of the study was to assess soybean response to rhizobia inoculation when grown in soils amended with urea or vermicompost to improve nitrogen levels. Two greenhouse experiments and one field trial at two sites were carried out. The first greenhouse experiment included soils from sixty locations, sampled from smallholder farms in Western Kenya. The second greenhouse experiment consisted of one soil selected among soils used in the first experiment where inoculation response was poor. The soil was amended with vermicompost or urea. In the two greenhouse experiments, Legumefix (inoculant) + Sympal (legume fertilizer blend) were used as a standard package. Results from the second greenhouse experiment were then validated in the field. Analysis of variance was done using SAS statistical software and mean separation was done using standard error of the difference for shoot biomass, grain yield nodulation, nodule effectiveness and nutrient uptake. In the first greenhouse trial, soybean response to inoculation was significantly affected by soil fertility based on nodule fresh weight and shoot biomass. Soils with low nitrogen had low to no response to inoculation. After amendment, nodule fresh weight, nodule effectiveness, nodule occupancy, and shoot dry biomass were greater in the treatment amended with vermicompost than those amended with urea (Legumefix + Sympal + vermicompost and Legumefix + Sympal + urea) respectively. Under field conditions, trends were similar to the second experiment for nodulation, nodule occupancy and nitrogen uptake resulting in significantly greater grain yields (475, 709, 856, 880, 966 kg ha〈sup〉−1〈/sup〉) after application of vermicompost at 0, 37, 74, 111, and 148 kg N ha〈sup〉−1〈/sup〉 respectively. It was concluded that soybean nodulation and biological nitrogen fixation in low fertility soils would not be suppressed by organic amendments like vermicompost up to 148 kg N ha〈sup〉−1〈/sup〉.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Eduardo Vázquez, Marta Benito, Mariela Navas, Rafael Espejo, Eugenio Díaz-Pinés, Nikola Teutscherova〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the Mediterranean rainfed agriculture, a summer fallow is necessary because of the severe drought and high temperatures. Due to suppressed plant nitrogen (N) uptake during this period, an accumulation of inorganic N in the soil may occur, which could be lost from the system during the first autumn rains. Both mineralization and nitrification rates can be affected by agricultural practices, such as tillage or liming, influencing the amount of available N present in the soil during the fallow period. In this study, we investigated the effects of two common agricultural practices, no-tillage (instead of traditional tillage) and liming, on soil gross N transformations during the summer fallow. Liming increased gross N mineralization (from 1.21 to 1.78 mg N kg〈sup〉−1〈/sup〉 day〈sup〉−1〈/sup〉) and gross nitrification (from 0.44 to 0.76 mg N kg〈sup〉−1〈/sup〉 day〈sup〉−1〈/sup〉) while traditional tillage increased N immobilization. Tillage did not affect gross nitrification but the effect of liming on gross N mineralization was enhanced in no-tillage plots. The total bacteria abundance was enhanced by liming and no-tillage and seemed to be responsible for gross N mineralization and immobilization. The gross mineralization, nitrification and microbial immobilization decreased during the summer fallow with an overall reduction by 40%, 56%, 74% and 54% in gross N mineralization, gross nitrification, ammonium immobilization and nitrate immobilization, respectively. The accumulation of ammonium could be interpreted as a consequence of the decoupling between ammonium production and consumption rates. The increase of gross N mineralization and nitrification caused by liming application could result in augmented risks of N losses via nitrate leaching and gaseous losses in autumn, especially under no-tillage. However further studies are required to elucidate the nitrate fate of the in Mediterranean agricultural soils under those management practices.〈/p〉〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 190〈/p〉 〈p〉Author(s): Xudong Zhang, Muhammad Kamran, Xuanke Xue, Ji Zhao, Tie Cai, Zhikuan Jia, Peng Zhang, Qingfang Han〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Utilizing ridge-furrow construction combined with plastic film mulching system (RFMS) is an effective strategy for improving crop productivity in semi-arid areas. However, the key mechanisms by which RFMS stimulates the integrated utilization of key production resources (thermal, water and radiation) to affect maize production is not well-defined. In the Loess Plateau of China, three treatments were applied in a two-year field experiment: 1) RFH with RFMS at a high coverage ratio (50 cm mulched ridge:10 cm unmulched furrow); 2) RFL with RFMS at a low coverage ratio (60 cm mulched ridge:60 cm unmulched furrow); and 3) FP as the control without mulching. RFMS significantly improved soil hydrothermal conditions, which enhanced photosynthesis and promoted canopy growth to intercept more radiation. With an increase of soil thermal time (〈em〉TT〈sub〉soil〈/sub〉〈/em〉) by 199.1–415.1 °C d compared with FP, the thermal effect of RFMS improved maize crop phenology by shortening the duration of vegetative stage to prolonging reproductive stage by 1–3 days, thereby prioritizing the allocation of the captured radiation, thermal and water to reproductive growth. These alterations significantly increased maize grain yield by 38.0–59.6%, and enhanced the efficient use of resources by 13.7–21.9% in thermal, 34.6–59.8% in water and 30.0–50.0% in radiation, which enhanced when increasing coverage (RFH vs. RFL). Overall, these alterations of RFMS on hydrothermal, as an adaptive strategy, can positively mark the capture and allocation of resources and the conversion of resources into biological materials (especially grains) in semi-arid areas like the Loess Plateau.〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 191〈/p〉 〈p〉Author(s): Miwa Arai, Go-Ichiro Uramoto, Maki Asano, Katsuyuki Uematsu, Kentaro Uesugi, Akihisa Takeuchi, Yuki Morono, Rota Wagai〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Organic matter (OM) in surface soil is largely present within porous mineral-dominant clusters called aggregates. Recent studies have shown the localization of OM within large macroaggregate structure based on synchrotron X-ray micro-computed tomography (μCT) coupled with a vapor-phase, osmium (Os)-staining pretreatment. Here we developed a new approach to identify OM locations within submillimeter-sized aggregates at higher spatial resolution and assessed its applicability using a well-characterized surface volcanic soil, an allophanic Andisol, under no-tillage with leaf compost addition. Water-stable aggregates (500–800 μm in diameter) were embedded in agarose, chemically fixed, and repeatedly stained by osmium tetroxide and thiocarbohydrazide, followed by gradual dehydration with ethanol and resin fixation. Scanning electron microscopy and μCT observation showed no signs of physical alteration during sample preparation. Energy-dispersive X-ray spectroscopy analysis of the microtome-cut surface of the aggregate identified plant detritus highly enriched in Os and much smaller amorphous OM (〈10 μm) that were high in Fe, Al, and Si as well as Os. Synchrotron μCT imaging by photon energies above and below Os L〈sub〉3〈/sub〉 X-ray absorption edge (10.87 keV) and subsequent image calculation showed the distribution of Os-stained voxels down to micrometer scale. The improved resolution compared to previous studies was partly attributable to liquid-state staining and thiocarbohydrazide bridging. Other advantages and some cautions of the proposed method were discussed.〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 191〈/p〉 〈p〉Author(s): Romina Fernández, Ileana Frasier, Alberto Quiroga, Elke Noellemeyer〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In order to obtain baseline values for the evaluation of soil degradation, the biological and physical quality of petrocalcic Paleustolls, of the calcrete plains of the Semiarid Region Pampa of Argentina, soils under agricultural (Ag) and native vegetation (NV) were selected, with the same clay content, in which three depth layers (upper, middle and lower) were sampled. Total organic carbon and its fractions, total nitrogen, soil texture, aggregate size distribution, mean weight diameter, aggregate volumetric weight, maximum bulk density, susceptibility to compaction, critical moisture content, hydraulic conductivity, infiltration, penetration resistance were determined. In addition, the size, distribution and shape of the macropores were measured through image analysis of thin sections. As biological indicators, respiration, microbial biomass carbon and nitrogen were determined. Soils under Ag use had lower carbon and nitrogen content, they also had lower total porosity and macroporosity compared to the NV soils, and the predominant shape of macropores was round. This change in the distribution and shape of the pores led to lower rates of infiltration and lower hydraulic conductivity, higher bulk density and greater resistance to penetration. The round macropores were found to be negatively correlated with organic carbon, total porosity and macroporosity and positively with indicators associated with compaction (maximum bulk density, susceptibility to compaction and bulk density). Compacted soils with lower total porosity and higher proportion of round macropores presented higher volumetric weight of the aggregates. The Ag soils with lower carbon and nitrogen content also had lower microbial biomass carbon and respiration, compared to the soils under natural vegetation, and the variables associated with compaction were negatively related to biological properties. The suggested minimum set of indicators included organic carbon, total porosity, mean weight diameter, macropores, penetration resistance, aggregates volumetric weight of 2–3-mm, elongated macropores, respiration and microbial biomass carbon. All of them were strongly related to indicators that reflect the physical, chemical and biological functionality of the soil that sustain soil-based ecosystem services. Degradation and rehabilitation processes might be governed by the feedback between pore formation and microbial activity, underpinning the importance of perennial crops and cover crops for providing substrate supply to the soil biota for sustainable agricultural systems.〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 191〈/p〉 〈p〉Author(s): Bing Lu, Nihong Liu, Huiling Li, Kefei Yang, Can Hu, Xufeng Wang, Zhengxuan Li, Zhixiong Shen, Xiuying Tang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Available nitrogen content reflects the nitrogen latest supply capacity of coco-peat. Rapid determination of available nitrogen content in coco-peat is of great significance for precision fertilization in precision agriculture. In this study, available nitrogen of coco-peat was rapidly and quantitatively detected by near-infrared (NIR) spectroscopy. The mathematical model between spectral data and measured available nitrogen values was established, and the impacts of different spectral pre-processing on the whole band modeling results were compared and analyzed. Successive projections algorithm (SPA) and elimination of uninformative variables (UVE) were applied to remove redundant and irrelevant information variables from original spectrum and various pre-processing spectra, and the corresponding PLSR and MLR spectral prediction models were established. Comparing the modeling results of using full-band spectral data and eliminating the irrelevant information spectral data, the optimal spectral prediction model was established by using MLR. And the model with filtered characteristic wavelength spectral data by SPA after Savitzky-Golay smoothing (S〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉G smoothing) pre-processing yielded optimum results with the correlation coefficients for calibration set (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈msub〉〈mi〉R〈/mi〉〈mi〉C〈/mi〉〈/msub〉〈/math〉) 0.996 and prediction set (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈msub〉〈mi〉R〈/mi〉〈mi〉P〈/mi〉〈/msub〉〈/math〉) 0.990; the root mean square errors for calibration set (RMSEC) and prediction set (RMSEP) were 4.634 mg/100 g and 7.203 mg/100 g, respectively; and the ratio of prediction to deviation (RPD) was 7.011. The results showed that fast quantitative detection of available nitrogen of coco-peat could be achieved by NIR spectroscopy, and it could provide a reference for the rapid detection of substrate fertilizer content in facility agriculture.〈/p〉〈/div〉

Description: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 189〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 191〈/p〉 〈p〉Author(s): Pirkko Mustamo, Anna-Kaisa Ronkanen, Örjan Berglund, Kerstin Berglund, Bjørn Kløve〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Detailed, accurate information on soil temperature is crucial for understanding processes leading to solute leaching and greenhouse gas (GHG) emissions from managed peat soils, but few studies have attempted to study these processes in detail. Drained peat soils have different characteristics from pristine peat. Cultivated peat soils, in particular, have high mineral matter content in the plough layer, due to mineralisation of peat and, sometimes, addition of mineral material. This study examined the effect of mineral matter content on thermal conductivity (λ) in partially frozen and unfrozen peat samples. Effect of change in temperature from −3 °C to −10 °C on thermal conductivity was also estimated. Three existing models for estimating the thermal conductivity of organic soils were assessed for their suitability for cultivated drained peat soils. The thermal conductivity of peat samples with three different levels of mineral matter content was determined, using the single probe method, in the saturated state and when subjected to at least two different matric potentials at five different temperatures (+10 °C, + 1 °C, −3 °C, −5 °C and −10 °C). The results showed that λ values differed between peat soils depending on mineral matter content, ice content and moisture content. The samples with the highest mineral matter content and bulk density had higher thermal conductivity at positive temperatures and to a lesser extent, at freezing temperatures, when volumetric water content and volume of water-free pores was similar. Most soil samples, especially those with no added mineral soil, were not fully frozen at −3 °C and −5 °C, but this had minor effect on thermal conductivity compared with values measured at −10 °C. The Brovka-Rovdan model proved reasonably good at predicting frozen thermal conductivity in sand-enriched peat soils, while the de Vries model proved best at estimating thermal conductivity for unfrozen peat samples. We provide a first estimate of the thermal conductivity of (partially) frozen cultivated peat measured using undisturbed samples. These results can be used to parameterise numerical heat transport models for simulating soil processes and GHG emissions.〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 191〈/p〉 〈p〉Author(s): S.H. Aday, M.N. Ramadhan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉A field experiments were conducted to compare the field performance of three subsoiler combinations using the draft force requirement and the disturbed area as comparison parameters. The subsoiler combinations are single tine, parallel arranged double tines and partially swerved double tines. The three subsoiler combinations were tested using four operating depths (30, 40, 50, and 60 cm) with and without wings in silty clay loam soil of moisture content (13.54%). The experiment design was randomized complete block design (4 × 2 × 3) with four replicates. The means of the treatments were compared using RLSD at probability level of 1%.〈/p〉 〈p〉The draft force requirements for S, PSS and PAS increased with operating depth and with wings addition. The mean of the draft force requirement for S, PSS and PAS are 15.30, 22.69 and 30.68 kN respectively. For the single tine of PSS, the draft force requirement is the lowest while for S was medium and for SSP is the highest; these values are 11.35, 15.18 and 15.30 kN respectively. The disturbed area for S, PSS and PAS increased with operating depth and with wings addition. The disturbed area for the three subsoiler combinations was as follows PAS 〉 PSS 〉 S. However, for PAS it was greater than that of PSS by only 3%, whereas, its draft force was greater than that for PSS by 8 kN. The field observations showed that PAS suffered from soil blockade which caused soil billing up in front of the two tines and that resulted in higher draft force requirement while, the contrary occurred with PSS, the soil easily flow between the two tines which reduced its draft force requirement. From the results and the field observations PSS surpassed S and PAS in giving better field performance.〈/p〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 191〈/p〉 〈p〉Author(s): Reza Keshavarz Afshar, Abdelaziz Nilahyane, Chengci Chen, Huaqin He, W. Bart Stevens, William M. Iversen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Conventional intensive tillage (CT) is widely practiced in sugarbeet (〈em〉Beta vulgaris〈/em〉 L.) growing regions. However, CT uses more labor and machinery and has negative impacts on soil and environment. Limited information exists for the performance of sugarbeet in reduced tillage compared to CT systems. A three-year field experiment was conducted to evaluate yield and quality of sugarbeet under no-till (NT), and strip-till (ST) systems compared to CT. The response of sugarbeet to the increasing rate of nitrogen (N) from 56 to 224 kg ha〈sup〉−1〈/sup〉 in each tillage system was also studied. Sugarbeet plant stand, root yield, root impurities (sodium, potassium, and amino-N concentration in the root), sucrose loss to molasses (SLM) and recoverable sucrose yield were measured. Tillage had no significant effect on plant stand, root yield, and recoverable sucrose yield. The estimated cost of tillage operation showed that growing sugarbeet under NT was 111 US$ ha〈sup〉−1〈/sup〉 less than that in CT, which could be translated into 111 US$ ha〈sup〉−1〈/sup〉 higher net benefit for growers considering the similar yields in both systems. Sugarbeet root yield linearly increased in response to increasing rate of N, however, sucrose concentration decreased and root impurities increased with increasing N input. Overall, little increase of recoverable sucrose yield was observed with N rate increasing from 56 to 224 kg ha〈sup〉−1〈/sup〉. Response to N rate occurred irrespective of tillage method.〈/p〉〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 190〈/p〉 〈p〉Author(s): Khaoula Abrougui, Karim Gabsi, Benoît Mercatoris, Chiheb Khemis, Roua Amami, Sayed Chehaibi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Tillage aims to prepare the soil with the adequate treatment to create the ideal and most favorable conditions for cultivation. To evaluate the effect of tillage systems on soil environment, it is mandatory to measure the modifications in physical, chemical and biological properties. In recent decades, artificial intelligence systems were used for developing predictive models to simplify, estimate and predict many farming processes. They are also employed to optimize performance and control risks. These systems have become true virtual helpers, and more so when integrated with predictive analytics. In the present study, the effects of tillage systems on soil properties and crop production and the predictive capabilities of multiple linear regressions (MLR) and artificial neural networks (ANN) are evaluated to estimate organic potato crop yield including soil microbial biomass (MB), soil resistance to penetration, soil organic matter (OM) and tillage system. Potato yield was found to be significantly impacted by tillage and soil properties. The results showed that MLR model estimated crop yield more accuracy than ANN model. Correlation coefficient and root mean squared (RMSE) were 0.97 and 0.077 between the measured and the estimated data by the ANN model, respectively. Generally, the ANN model showed greater potential in determining the relationship between potato yield, tillage and soil properties.〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 191〈/p〉 〈p〉Author(s): Remigio Paradelo, Marie Eden, Ingrid Martínez, Thomas Keller, Sabine Houot〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Recycling composted organic residues in agriculture can reduce the need for mineral fertilizers and improve the physicochemical and biological properties of cultivated soils. However, more studies dealing with soil physical properties after compost amendment are still needed. The objective of this study was to investigate the impact of long-term compost amendment on soil physical properties in a silt loam Luvisol under a maize-wheat rotation in the Paris Basin. Since 1998, three composts and one manure were applied every second year after wheat harvest, at a rate of ca. 4 Mg C ha〈sup〉−1〈/sup〉. Bulk density, organic carbon concentration on a mass basis, water holding capacity, gas transport properties and Atterberg limits were measured on topsoil samples taken 15 years after the beginning of the experiment. Soil moisture was monitored in the field down to a depth of 160 cm during two years with different climatic conditions: a year with a dry summer (2010) and a year with a wet summer (2012). Compost and manure amendments reduced bulk density and increased organic carbon concentrations, which improved apparent air permeability and gas diffusivity, but only one of the amendments (a green waste-sewage sludge compost) increased water-holding capacity. The amendments also increased the water contents at the Atterberg limits and overall produced better soil conditions for tillage and other agricultural operations, in particular in wet years. However, field moisture measurements showed that in general, soil water contents were not higher in the amended soils than in the control at any of the periods considered.〈/p〉〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 190〈/p〉 〈p〉Author(s): Murilo G. Veloso, Diego Cecagno, Cimélio Bayer〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Both no-tillage and legume cover crops have been shown to increase soil organic carbon (SOC) in subtropical soils. However, the mechanisms underpinning management system effects on SOC accumulation are still not well understood. We used a combination of aggregate size and density fractionation to elucidate these mechanisms at a 30-year old experiment on an Acrisol in southern Brazil. The effects of two tillage systems [conventional system (CT) and no-tillage (NT)] combined with three cropping systems [oat/maize (O/M), vetch/maize (V/M) and oat + vetch/maize + cowpea (OV/MC)] were evaluated in the top 20 cm soil layer. Overall, macroaggregation (〉0.25 mm) was significantly influenced by tillage with NT showing values 14% greater than CT in the 0–5 cm soil depth. On average, the occluded light fraction-C content in macroaggregates was more than twice as high under NT compared to CT (4.4 〈em〉vs〈/em〉. 1.8 g kg〈sup〉−1〈/sup〉). This effect was more pronounced when legume cover crops were grown. However, the most significant effect of cover crops was observed in the organomineral fraction of microaggregates, especially under NT (12.1 under O/M and 19.8 g kg〈sup〉−1〈/sup〉 under OV/MC). Our results suggest that, although NT increased the occluded light fraction-C compared to CT, this effect was smaller than the gains that legume cover crops offered in organomineral association.〈/p〉〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 190〈/p〉 〈p〉Author(s): Vikas Rai, P. Pramanik, T.K. Das, P. Aggarwal, Ranjan Bhattacharyya, P. Krishnan, V.K. Sehgal〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Limited information is available about the effects of conservation agriculture (CA) practices on soil temperature moderation and distribution of water in the soil profile during crop growth, particularly on the changes in the components of water and energy balance. Hence, the objective of this study was to assess soil hydrothermal regimes and water and energy balance components in pigeon pea (〈em〉Cajanas cajan〈/em〉) grown under CA in a pigeon pea-wheat (〈em〉Triticum aestivum〈/em〉) cropping system using the Hydrus-2D model. There were seven treatments: permanent broad bed (PBB), PBB with crop residue (PBB + R), permanent narrow bed (PNB), PNB with crop residue (PNB + R), zero tillage (ZT), ZT with crop residue (ZT + R), and conventional tillage (CT). Results during the seventh year of the experiment showed that the PBB, PBB + R, PNB, PNB + R and ZT + R treatments significantly reduced surface soil bulk density (BD), increased field saturated hydraulic conductivity (K〈sub〉sat〈/sub〉) and improved soil water retention over the CT. The K〈sub〉sat〈/sub〉 values obtained as the output of the Rosetta-Lite model which is implemented in Hydrus-2D) were very low. Hence, experimentally measured K〈sub〉sat〈/sub〉 values were optimized along with parameters α and n that were obtained as output of the Rosetta Lite model, through inverse modelling (IM). The model predicted daily changes in profile soil water content (SWC) with reasonable accuracy (R〈sup〉2〈/sup〉 = 0.77, RMSE = 0.012; n = 84). Soil water balance simulated from the model indicated higher cumulative transpiration (CTr), lower cumulative evaporation (CE) and higher soil water retention in the PNB + R and PBB + R plots than CT. Computed values of thermal conductivity (λ) obtained from the observed soil temperature (ST) data at different SWC values showed significant correlations with those optimized through IM. In general, Hydrus-2D model over-predicted the ST values during a simulation period of 10 days. However, reasonably accurate (R〈sup〉2〈/sup〉 = 0.91, RMSE = 1.41 °C; n = 102) predictions were observed for the 0–20 cm soil layer using the optimized values. It was also observed that PBB + R and PNB + R treatments improved soil hydrothermal regimes, root growth, radiation interception, leaf area index and biomass production of the pigeon pea crop. Hydrus-2D used in this study could also satisfactorily simulate the temporal changes in energy balance components, such as soil heat flux (G) and evaporative heat flux (LE). Hence, this model may be adopted for evaluating arable management practices for characterizing different components of water and energy balance in pigeon pea.〈/p〉〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 190〈/p〉 〈p〉Author(s): Robert C. Schwartz, Alan J. Schlegel, Jourdan M. Bell, R. Louis Baumhardt, Steven R. Evett〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉There are significant uncertainties in partitioning growing season precipitation into the water balance components that determine water available for dryland crop yield across a range of environments and tillage practices. We evaluated profile soil water contents at a high temporal resolution during phases of a dryland wheat (〈em〉Triticum aestivum〈/em〉 L.) –sorghum (〈em〉Sorghum bicolor〈/em〉 L.) -fallow rotation under no tillage (NT)〈sup〉1〈/sup〉 and stubble-mulch tillage (ST) management at Bushland, Texas and Tribune, Kansas to assess event-based soil water balance components. Cumulative infiltration and evaporation were estimated based on hourly changes in stored soil water using a water balance approach and a drainage model. Estimated deep drainage comprised a small proportion of the soil water budget averaging five percent of annual precipitation in Bushland. Tillage did not significantly influence cumulative infiltration during summer fallow and growing season periods at Bushland. In contrast, NT at the Tribune location exhibited significantly greater (P = 0.023) cumulative infiltration compared to ST during the wheat fallow period just prior to sorghum planting. At both locations during summer fallow periods, NT was not more efficient in increasing stored soil water over that obtained with ST. Evaporation during summer fallow periods was more a function of the soil water content near the surface than the tillage practice. Effective infiltration expressed as a fraction of precipitation averaged 0.55 and 0.57 under NT and ST, respectively, at Bushland compared with 0.83 and 0.52 under NT and ST, respectively, at Tribune. Observations of effective infiltration elucidate historical results of the incremental sorghum grain yield response of NT over ST that averaged 12 percent at Bushland and 35 percent at Tribune. Partitioning of growing season precipitation to transpiration was insufficient in Bushland to generate yield increases under NT of similar magnitude to that observed in Tribune demonstrating that NT does not perform similarly across all environments.〈/p〉〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 190〈/p〉 〈p〉Author(s): S. Nawar, A.M. Mouazen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Accurate on-line visible and near infrared (vis-NIR) spectroscopy prediction of soil organic carbon (OC) is essential for food security and environmental management. This paper aims at using on-line vis-NIR spectra coupled with random forest (RF) modelling approach for the prediction of soil organic carbon (OC), comparing between single field (SF), non-spiked UK multiple-field (NSUK) and spiked UK multiple-field (SUK) calibration models. Fresh soil samples collected from 6 fields in the UK (including two target fields) were scanned with a fibre-type vis-NIR spectrophotometer (tec5 Technology for Spectroscopy, Germany), with a spectral range of 305–2200 nm. After dividing spectra into calibration and independent validation sets, RF was run on the calibration set to develop calibration models for OC for the three studied datasets. Results showed that the model prediction performance depends on the dataset used and varies between fields. Less accurate prediction performance was obtained for the on-line prediction compared to laboratory (samples scanned in the laboratory under non-mobile measurement) prediction, and for non-spiked models compared to spiked models. The best model performance in both laboratory and on-line predictions was obtained when samples from the SF were spiked into the UK samples, with coefficients of determination (R〈sup〉2〈/sup〉) values of 0.80 to 0.84 and 0.74 to 0.75, root mean square error of prediction (RMSEP) values of 0.14% and 0.17 to 0.18%, and ratio of prediction deviation (RPD) values of 2.30 to 2.5 and 1.98 to 2.04, respectively. Therefore, these results suggest that RF modelling approach when coupled with spiking provides high prediction performance of OC under both non-mobile laboratory and on-line field scanning conditions.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Tongchuan Li, Yuhua Jia, Ming’an Shao, Nan Shen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As ecosystem engineers, soil-inhabiting ants can influence soil properties in different ways. However, limited attention has been directed toward the role of 〈em〉Camponotus japonicus〈/em〉 on litter decomposition in the Loess Plateau. This study quantified the impact of 〈em〉C. japonicus〈/em〉 mounds on soil evaporation, temperature and litter decomposition. The distribution and physical properties of 〈em〉C. japonicus〈/em〉 mounds in four slopes (61 m × 5 m) under different vegetation types [Korshinsk peashrub (〈em〉Caragana korshinskii K.〈/em〉), KOP; purple alfalfa (〈em〉Medicago sativa〈/em〉 L.), ALF; natural fallow, NAF; and millet, MIL] were studied. The density of ant mounds in grass and shrublands was considerably higher than that in croplands. Farming activities and intense soil erosion in the crop slope could play a negative role in mound density. On average, half-ellipsoid ant mounds were 2.48 cm in height and 755 cm〈sup〉2〈/sup〉 in basal area with 0.75 g/cm〈sup〉3〈/sup〉 bulk density. The size distribution of the ant mounds was as follows: 2–3 (6.9%), 1–2 (27.3%), 0.5–1 (16.9%), 0.28–0.5 (18.2%) and 〈0.28 mm (30.7%). Porous ant mounds that covered the leaf litter of ALF reduced soil evaporation, increased soil temperature and indirectly accelerated leaf litter decomposition. Concentrations of soil organic matter (SOC), total N, ammonium N, nitrate N, available P and available K were higher in soil under ant mounds than those in surrounding soil under KOP, ALF and NAF. High soil moisture and temperature in the leaf litter and enhanced contact area between the soil particles and the leaf litter promoted litter decomposition and contributed to the formation of a ‘fertile island’. These findings may enrich our understanding on the effects of ant activity on soil ecosystems in semiarid areas.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 194〈/p〉 〈p〉Author(s): Liangang Xiao, Rongqin Zhao, Nikolaus J. Kuhn〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Conservation agriculture (CA) represents an efficient agro-ecosystems management for sustained crop production under the circumstances of global warming. However, the relative importance of three principles of CA has not been comprehensively assessed. Consequently, it has caused a controversy of whether no tillage (NT) is beneficial for crop yield improvement compared to conventional tillage, ranging from significant decrease to significant or insignificant increase. It remains unclear whether such a controversy is caused by statistical methodology or different acknowledge of the CA principles. This study aimed to clarify the relative importance of various tillage and straw mulching practices in crop yield, evapotraspiration (ET), and water use efficiency (WUE). Published data from experiments reporting the effects of CA on changes of crop yield and water use on the Chinese Loess Plateau were collected. A database of 49 sets of paired experiments was compiled, with tillage practices including conventional tillage without straw mulching (CT), conventional tillage with straw mulching (CTs), no tillage without straw mulching (NT), no tillage with straw mulching (NTs), reduced tillage without straw mulching (RT), reduced tillage with straw mulching (RTs), and subsoiling with straw mulching (Ss). Variable-controlling approach was used to divide these practices into reasonable groups. Paired t-tests were further conducted to systematically evaluate the relative importance of tillage reduction and straw mulching. The results showed the sole application of straw mulching as well as the combination of straw mulching and tillage reduction both resulted in a significant increase of crop yield. Tillage reduction itself including NT and RT caused a significant crop yield decline. The sole application of tillage reduction or straw mulching has neutral or negative impacts, whereas the combination of tillage reduction and straw mulching has neutral to positive on ET changes. WUE changes were similar to that of crop yield. The results illustrated that the increased crop yield reported on the Loess Plateau area is mainly due to the application of straw mulching, rather than the adoption of NT. The positive influences of CA practices on crop yield and water use tend to be higher under dry climate conditions compared to humid climate conditions. In addition, the adoption of paired t-test significantly improves the evaluation of the effects of CA compared to one way-ANOVA (LSD). Overall, the results help clarify the higher importance of straw mulching over tillage reduction and therefore challenge the centrality of NT in crop yield and WUE improvement.〈/p〉〈/div〉