ALBERT

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 353〈/p〉 〈p〉Author(s): Jingzhe Wang, Jianli Ding, Danlin Yu, Xuankai Ma, Zipeng Zhang, Xiangyu Ge, Dexiong Teng, Xiaohang Li, Jing Liang, Ivan Lizaga, Xiangyue Chen, Lin Yuan, Yahui Guo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil salinization is one of the most important causes for land degradation and desertification and is an important threat to land management, farming activities, water quality, and sustainable development in arid and semi-arid areas. Soil salinization is often characterized with significant spatiotemporal dynamics. The salt-affected soil is predominant in the Ebinur Lake region in the Northwestern China. However, detailed local soil salinity information is ambiguous at the best due to limited monitoring techniques. Nowadays, the availability of Multi-Spectral Instrument (MSI) onboard Sentinel-2, offers unprecedented perspectives for the monitoring and mapping of soil salinity. The use of MSI data is an innovative attempt for salinity detection in arid land. We hypothesize that field observations and MSI data and MSI data-derived spectral indices using the partial least square regression (PLSR) approach will yield fairly accurate regional salinity map. Based on electrical conductivity of 1:5 soil:water extract (EC) of 72 ground-truth measurements (out of 116 sample sites) and various spectral parameters, such as satellite band reflectance, published satellite salinity indices, red-edge indices, newly constructed two-band indices, and three-band indices from MSI data, we built a few inversion models in an attempt to produce the regional salinity maps. Different algorithms including Pearson correlation coefficient method (PCC), variable importance in projection (VIP), Gray relational analysis (GRA), and random forest (RF) were applied for variable selection. The results suggest that both the newly proposed normalized difference index (NDI) [(B12 − B7) / (B12 + B7)] and three-band index (TBI4) [(B12 − B3) / (B3 − B11)] show a better correlation with validation data and could be applied to estimate the soil salinity in the Ebinur Lake region. The established models were validated using the remaining 44 independent ground-based measurements. The RF-PLSR model performed the best across the five models with R〈sup〉2〈/sup〉〈sub〉V〈/sub〉, RMSE〈sub〉V〈/sub〉, and RPD of 0.92, 7.58 dS m〈sup〉−1〈/sup〉, and 2.36, respectively. The result from this model was then used to map the soil salinity over the study area. Our analyses suggest that soil salinization changes quite significantly in different seasons. Specifically, soil salinity in the dry season was higher than in the wet season, mostly in the lake area and nearby shores. We contend that the results from the study will be useful for soil salinization monitoring and land reclamation in arid or semi-arid regions outside the current study area.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 353〈/p〉 〈p〉Author(s): Roozbeh Moazenzadeh, Babak Mohammadi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Root zone temperature is one of the most important soil characteristics, controlling many of the physical, chemical and biological processes in the soil. Temperature varies by soil depth, and exerts a profound impact on plant germination and growth. In this study, the accuracy of two artificial intelligence models including support vector regression (SVR) and elman neural network (ENN) and their hybrids with firefly algorithm (SVR-FA and ENN-FA) and krill herd algorithm (SVR-KHA and ENN-KHA) was assessed in estimating soil temperature (Ts) at 5, 10, 20, 30, 50 and 100 cm depths at Maragheh meteorological station in north-western Iran. The results of the models were evaluated under 5 scenarios with various inputs including the main meteorological parameters measured at the station (air temperature, sunshine hours, relative humidity, wind speed and saturation vapour pressure deficit). Daily Ts data recorded from January 1, 2006 to December 30, 2012 and from January 1, 2013 to December 30, 2015 were used for model training and testing, respectively. The results showed that error rates have decreased from 5 to 10 cm soil depth (root mean square error (RMSE) reduced by 2.97, 4.68 and 3.19% for the best scenarios of SVR, SVR-FA and SVR-KHA models, respectively), whereas error rates have been increasing from 10 to 100 cm soil depths (RMSE increased by 62.4, 80.9 and 73.6% for the best scenarios of SVR, SVR-FA and SVR-KHA models, respectively). For the best scenarios of ENN, ENN-FA and ENN-KHA models, RMSE values decreased by 2.1, 1.6 and 3.1% from 5 to 10 cm depth and increased by 61.1, 84.1 and 81.1% from 10 to 100 cm depth, so that all six models reached their best performance at 10 cm soil depth. Examination of the results in terms of under-estimation or over-estimation of Ts indicated that the lowest and highest differences in performance between under- and over-estimation sets were 0.01 °C (SVR-FA at 5 cm depth) and 1.64 °C (SVR at 100 cm depth) for SVR-based models and 0 °C (ENN at 10 cm depth) and 0.56 °C (ENN at 100 cm depth) for ELM-based models, respectively. According to the results from the best scenarios of SVR, SVR-FA and SVR-KHA models in the under-estimation set at 100 cm depth, all the three models have exhibited a poorer performance over the temperature range 15–25 °C (RMSE increased by 56.7, 47 and 61.3% for SVR, SVR-FA and SVR-KHA, respectively) compared to temperature values outside that range. Exactly the same trend was also observed for ELM-based models, where the mentioned increases in RMSE were about 37.7, 59.4 and 55.5% for ELM, ELM-FA and ELM-KHA, respectively. According to the results, bio-inspired metaheuristic optimisation algorithms based on SVR and ENN which use appropriate meteorological parameters as inputs can have a relatively satisfactory performance in estimating Ts under climatic conditions similar to our study area, especially in lower depths, and can be used as an alternative to direct measurement of this important parameter.〈/p〉〈/div〉 〈/div〉

Description: A mixture of red and blue light-emitting diodes (LEDs; at a ratio of 7:3, respectively) were used to analyze the effects of different photosynthetic photon flux densities (PPFDs) (40, 80, and 120 µmol m−2 s−1 hereafter known as LED 40, 80, and 120, respectively) on the micropropagation of Gerbera jamesonii Bolus shoots. The experiment also examined the effect of 6-benzyladenine (BA) in 1, 2.5, and 5 µM concentrations in the media. Biometrical observations and analyses of leaf morphometry and photosynthetic pigment content were conducted. Shoot multiplication increased with an increasing BA concentration. A PPFD of 80 µmol m−2 s−1 and 5 µM BA is suggested as efficient for shoot propagation and economically viable. LED 120 increased the leaf blade area and its width, and circularity and elongation ratios. The intensity of light did not affect the fresh weight, which increased at higher BA concentrations (2.5 and 5 μM). The dry weight content decreased with increasing cytokinin concentration; the greatest content was observed on media with 1 µM BA under PPFD 120 µmol m−2 s−1. LED 80 increased the photosynthetic pigments content in the leaves in comparison to the standard intensity of LED 40. Increased BA concentration raises the content of chlorophyll a.

Description: Soil pH is a key factor affecting the growth of blueberries. Understanding the response mechanism of blueberries to different pH values and selecting suitable evaluation indexes are the basis of breeding new blueberry cultivars with high pH tolerances. The effects of different soil pH treatments for 17 months on the plant growth, fruit yield, photosynthetic characteristics, and leaf microelement concentration of Vaccinium ashei Reade ‘Climax’ and V. corymbosum hybrid ‘Chaoyue No. 1′ were studied. Plant height, main stem diameter, branch number per plant, leaf dry weight, stem dry weight, root dry weight, and total dry weight decreased with increasing soil pH. With an increase in soil pH, the first flowering date, 50% flowering date, first ripening date, and 50% ripening date of the two cultivars were postponed, and the flower bud numbers per plant, the floret numbers per bud, and yield per plant showed a downward trend. Moreover, the fruit quality decreased, which was reflected in the increase in the titratable acid content (TA) and the decrease in the total soluble solids content (TSS) and the TSS:TA ratio in the high pH treatment. With increasing soil pH, the chlorophyll content index (CCI), maximal photochemical efficiency of the PSII (Fv/Fm), quantum photosynthetic yield of the PSII (Y(II)) and net photosynthetic rate (Pn) of the two cultivars showed a downward trend, and some microelement concentrations in the leaves were imbalanced. Under high pH treatment, ‘Chaoyue No. 1′ had a relatively higher plant biomass and fruit yield, so it had a stronger tolerance to high pH than ‘Climax’ did. More strongly acidified rhizosphere soil capacity, as well as higher CCI, Fv/Fm, Y(II), and Pn values were the main reasons for the high pH tolerance of ‘Chaoyue No. 1′. Compared with destructive biomass indicators such as plant weight, nondestructive indicators such as CCI, Fv/Fm, and Y(II) can be more valuable indicators for fast and accurate evaluation of blueberry tolerance to high pH at early stages of treatment.

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 353〈/p〉 〈p〉Author(s): Lingfei Yu, Yue Chen, Wenjuan Sun, Yao Huang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Globally, excessive grazing is identified as one of the key disturbances leading to grassland degradation and soil carbon (C) loss. Grazing exclusion has been proposed as an effective practice to restore degraded grasslands and to promote C sequestration. However, there is still little knowledge about how soil C changes with grazing exclusion in high-altitude alpine ecosystems with very cold climates. We synthesized data from 63 sites in the literature and 15 sites in a field sampling and investigated the dynamics of soil C stocks following grazing exclusion in alpine grasslands of the Tibetan Plateau. The results showed that the soil C stock increased with grazing exclusion at most sites, with average C sequestration rates of 0.84, 0.58, and 0.49 Mg ha〈sup〉−1〈/sup〉 yr〈sup〉−1〈/sup〉 in the soil layers of 0–10, 10–20, and 20–30 cm, respectively. Based on these results, if 60 million ha of the grasslands on Tibetan Plateau were excluded from grazing livestock by 2020 according to the national plan, then approximately 0.11 Pg C yr〈sup〉−1〈/sup〉 would be sequestered in the soil which equates to about 4.4% of fossil fuel and cement CO〈sub〉2〈/sub〉 emissions in China in 2013. Generally, the rates of soil C increase exhibited a declining pattern with increasing years of grazing exclusion, with a significant decrease occurring after ten years of grazing exclusion. Of the factors examined, the rates of absolute and relative soil C change were both positively related to mean annual precipitation but negatively related to the year of grazing exclusion and initial soil C stock, respectively. The rates of soil C changes increased linearly with those of N change, and no matter how soil C changed (whether it increased or decreased), soil C:N ratios remained stable over the years of grazing exclusion. Our results implied that grazing exclusion is beneficial for soil C sequestration in degraded alpine grassland, especially in humid areas. Moreover, the intrinsic increase in N could keep up with the pace of soil C changes and would sustain soil C sequestration during the recovery process.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 353〈/p〉 〈p〉Author(s): Thomas P. D'Avello, William J. Waltman, Sharon W. Waltman, James A. Thompson, Joseph Brennan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We examine the climatic record of the conterminous United States from 1895 to 2014 as expressed through the PRISM dataset and the jNewhall model. Specifically, the zero line of the Annual Water Balance (AWB) and the respective oscillation zone through its longitudinal extent is examined. The zero line corresponds to the Pedocal/Pedalfer line defined by C.F. Marbut, considered outdated in current pedological circles, but conceptually powerful in denoting regional negative vs. positive AWB. Soil Moisture Regimes are reviewed and a means of expressing Soil Moisture Regime variability is introduced. Results indicate a difference in the width of the AWB oscillation zone from South to North with a demarcation approximating 40 degrees North Latitude. PRISM data is verified from a select set of National Weather Service station data to assess the utility of using readily accessible PRISM data for performing similar work by others. The effect of climate variables on organic carbon (OC) stock and depth of maximum Calcium Carbonate concentration is examined for a suite of soils along a climo-sequence from North Dakota to Central Iowa and found to account for a mild amount of the variability of both variables.〈/p〉〈/div〉 〈/div〉

Description: Due to its possible utilization in cosmetics, medicine and crop protection, as a valuable alternative to petrochemical-derived products, hemp essential oil is now considered a product with high value added and a promising marketing potential. This experiment was conducted with the aim of evaluating the effect of four different locations of Northern Italy during two years (four environments) and three hemp monoecious varieties on the production and quality of essential oils (EOs) obtained by inflorescences harvested at full flowering of female flowers. The highest inflorescence yield was obtained at Maiano 2017, where a superficial groundwater layer (1.5 m) was present, with values that ranged from 1.69 of Fedora to 2.06 t ha−1 of Futura. EOs production ranged between 3.4 and 4.9 L ha−1, affected mainly by the variety effect. The terpene in EOs, very similar between varieties and environments, was mainly composed of sesquiterpenes (caryophillene and humulene, as the most abundant) rather than monoterpenes (α-pinene, β-myrcene and trans-β-ocimene, in particular). Phytocannabinoids, and in particular cannabidiol (CBD), were not removed from tissues by the steam during hydrodistillation, and if this is confirmed by further experiments, the residual biomass, now considered as waste, could assume significant importance as a source for further utilization.

Description: The role of small bioactive molecules (〈500 Da) in mechanisms improving resource use efficiency in plants under stress conditions draws increasing interest. One such molecule is omeprazole (OMP), a benzimidazole derivative and inhibitor of animal proton pumps shown to improve nitrate uptake and exclusion of toxic ions, especially of chloride from the cytosol of salt-stressed leaves. Currently, OMP was applied as substrate drench at two rates (0 or 10 μM) on hydroponic basil (Ocimum basilicum L. cv. Genovese) grown under decreasing NO3−:Cl− ratio (80:20, 60:40, 40:60, or 20:80). Chloride concentration and stomatal resistance increased while transpiration, net CO2 assimilation rate and beneficial ions (NO3−, PO43−, and SO42−) decreased with reduced NO3−:Cl− ratio under the 0 μM OMP treatment. The negative effects of chloride were not only mitigated by the 10 μM OMP application in all treatments, with the exception of 20:80 NO3−:Cl−, but plant growth at 80:20, 60:40, and 40:60 NO3−:Cl− ratios receiving OMP application showed maximum fresh yield (+13%, 24%, and 22%, respectively), shoot (+10%, 25%, and 21%, respectively) and root (+32%, 76%, and 75%, respectively) biomass compared to the corresponding untreated treatments. OMP was not directly involved in ion homeostasis and compartmentalization of vacuolar or apoplastic chloride. However, it was active in limiting chloride loading into the shoot, as manifested by the lower chloride concentration in the 80:20, 60:40, and 40:60 NO3−:Cl− treatments compared to the respective controls (−41%, −37%, and −24%), favoring instead that of nitrate and potassium while also boosting photosynthetic activity. Despite its unequivocally beneficial effect on plants, the large-scale application of OMP is currently limited by the molecule’s high cost. However, further studies are warranted to unravel the molecular mechanisms of OMP-induced reduction of chloride loading to shoot and improved salt tolerance.

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 353〈/p〉 〈p〉Author(s): Zengming Chen, Yehong Xu, Daniela F. Cusack, Michael J. Castellano, Weixin Ding〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nitrogen (N) input rapidly increases available N in natural and managed ecosystems, potentially altering key ecosystem processes like decomposition. The effect of N enrichment on decomposition rates may be affected by the chemical quality of organic matter (OM), and the extent of N increment. Manure decomposition is an important process in agricultural systems, releasing nutrients and contributing to carbon (C) cycling. However, its response to N fertilization is poorly understood. To help address this knowledge gap, we decomposed pig manure (PM) and chicken manure (CM) under two rates of N fertilization (N1, 75 kg N ha〈sup〉−1〈/sup〉; N2, 112.5 kg N ha〈sup〉−1〈/sup〉) in a cropland in northeast China. We used litterbags to determine the dynamics of manure decomposition, while monitoring changes in the molecular composition with solid-state 〈sup〉13〈/sup〉C nuclear magnetic resonance (NMR) spectroscopy. After one-year, the decomposition rate of PM was significantly greater than CM (0.516 vs. 0.483 year〈sup〉−1〈/sup〉). Spectra of 〈sup〉13〈/sup〉C NMR indicated that PM initially contained more 〈em〉O〈/em〉-alkyl C and di-〈em〉O〈/em〉-alkyl C (representing cellulose). In contrast, the contents of alkyl C (representing lipids) and aromatic C (representing lignin) were less in PM than CM, such that PM was overall more easily degradable. There was no N rate effect on CM decomposition. However, the decomposition rate of PM was significantly lower under high N than low N (0.410 vs. 0.622 year〈sup〉−1〈/sup〉), apparently related to suppressed degradation of 〈em〉O〈/em〉-alkyl C and di-〈em〉O〈/em〉-alkyl C. This result was surprising, since N enrichment is generally expected to promote degradation of more labile compounds like cellulose. At the same time, the loss of syringyl monomer of lignin in PM was reduced by high N fertilization. Together, these results suggest that decreased losses of 〈em〉O〈/em〉-alkyl C and di-〈em〉O〈/em〉-alkyl C may have resulted from physical association of cellulose with more resistant lignin compounds. Net N mineralization was observed from manure decomposition and was greater for CM than PM, and high N fertilization suppressed N release from PM. Overall, our findings suggest that high rate of N fertilization may slow the decomposition of otherwise labile manure, potentially promoting greater C retention in soils.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 352〈/p〉 〈p〉Author(s): Sibylle Faust, Heinz-Josef Koch, Rainer Georg Joergensen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Undisturbed soils columns were transplanted from three tillage treatments at four sites in Central Germany to one site to investigate the relations between the CO〈sub〉2〈/sub〉 efflux, soil temperature (T〈sub〉S〈/sub〉) and volumetric water content (VWC) over one year in an unplanted period and maize (〈em〉Zea mays〈/em〉 L.) planted period. No tillage and grubber, i.e. rigid‑tine cultivator, (10-15 cm) systems contain higher stocks of microbial biomass C (MBC) in comparison with mouldboard ploughing (25-30 cm). This must be due to a reduction in microbial turnover, because higher VWC reduces T〈sub〉S〈/sub〉. At 5 cm depth, VWC was lowest with plough tillage throughout the year. At 15 cm depth, VWC was highest with grubber tillage during the planted period. During the unplanted period, mean T〈sub〉S〈/sub〉 was generally highest with grubber tillage. During the planted period, mean difference in T〈sub〉S〈/sub〉 increased in the order no tillage 〈 plough 〈 grubber at 5 cm depth and in the order plough 〈 grubber 〈 no-tillage at 15 cm depth. Mean CO〈sub〉2〈/sub〉 efflux was 1.12 t C ha〈sup〉−1〈/sup〉 in the unplanted and 2.85 t C ha〈sup〉−1〈/sup〉 in the planted period. Multiple linear relationships showed that T〈sub〉S〈/sub〉 and VWC explained 70.4% of the variance in CO〈sub〉2〈/sub〉 evolution rates in the unplanted and 37.2% in the planted period. T〈sub〉S〈/sub〉 effects generally dominated and showed similar regression coefficients in both periods. VWC had smaller effects, which were positive in the unplanted period and negative in the planted period. Significant tillage × T〈sub〉S〈/sub〉 interactions were observed in the unplanted period and tillage × VWC interactions in the planted period. Interactions were caused by strong positive T〈sub〉S〈/sub〉 effects with grubber tillage in the unplanted period and by strong negative VWC effects with plough tillage in the planted period. From a soil ecological viewpoint, grubber and no tillage can be recommended, as it improves microbial life conditions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 353〈/p〉 〈p〉Author(s): Shangqi Xu, Xia Liu, Xiujun Li, Chunjie Tian〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Wetland restoration has been conducted worldwide due to the important ecological functions provided by wetlands. However, the global patterns of soil organic carbon (SOC) change following wetland restoration are not clear, which has limited the efficacy of the management of restored wetlands. In this study, we synthesized the results from 41 studies and carried out a meta-analysis to examine the SOC dynamics following wetland restoration and the underlying mechanisms. The SOC of restored wetlands was 13.8% (〈em〉p〈/em〉 = 0.017) higher than that of cultivated wetlands and 29.2% (〈em〉p〈/em〉 〈 0.001) lower than that of natural wetlands. Wetland restoration facilitated SOC sequestration under certain conditions, including when the wetlands were restored via water supplementation, had seasonal hydrology in their natural status (before cultivation), were peatlands, occurred under a temperate climate, were restored for 6 to 10 years, or had been cultivated no longer than 15 years before restoration. Meanwhile, some conditions had negative effects on SOC sequestration, including wetlands under a tropical climate, those restored using a plantation approach, and those with a tidal hydrology after restoration. Model selection analysis suggested that the hydrological conditions of cultivated wetlands, soil depth, vegetation type, peat condition and restored age were important influential factors affecting SOC after wetland restoration, with the first 2 being the most important influential factors. Our results indicate that wetland restoration is inefficient in terms of SOC recovery and that wetland restoration to recover SOC is urgently needed and should be conducted more appropriately. The results of this study provide theoretical support for wetland management with the aim of SOC sequestration.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 353〈/p〉 〈p〉Author(s): Xiaoting Xie, Yili Lu, Tusheng Ren, Robert Horton〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Information on soil thermal properties is needed for estimating soil temperature (〈em〉T〈/em〉) and heat flux. However, few datasets are available for assessing the effects of soil thermal diffusivity (κ) parameterization on diurnal 〈em〉T〈/em〉 estimations. In this study, three κ parameterization methods, all based on soil physical properties, are compared for determining the responses of 〈em〉Τ〈/em〉 estimation to κ on two field soils. Among the three methods, two are the combination of the de Vries heat capacity model with either the McCumber and Pielke thermal conductivity model (MP-D) or the Johansen thermal conductivity model (J75-D), and the other one is the Xie et al. κ model (X18). The harmonic approach was used to estimate 〈em〉T〈/em〉 in the 0- to 5-cm layer on a sandy loam soil, and in the 5- to 10-cm layer on a silty clay loam soil from the measured 〈em〉T〈/em〉 data at a single depth. The J75-D and X18 methods produced close κ values, while the κ values from the MP-D method deviated significantly from that of other models. The 〈em〉T〈/em〉 results from the J75-D and X18 based harmonic methods agreed well with 〈em〉T〈/em〉 measurements. On the sandy loam soil, 〈em〉T〈/em〉 estimates from the MP-D method had a RMSE (root mean square error) of 3.04 °C and an RSR (ratio of RMSE to the standard deviation of the observations) of 0.53, while smaller RMSE and RSR values were obtained from the X18 method (1 °C and 0.17) and J75-D method (0.8 °C and 0.14). For the silty clay loam soil, the RMSE and RSR of 〈em〉T〈/em〉 estimates from the MP-D-based harmonic method were 0.82 °C and 0.27, respectively, which were larger than those (0.57 °C and 0.19) of the X18 and J75-D-based harmonic method. We concluded that the X18 and J75-D based harmonic methods could provide more accurate soil profile 〈em〉Τ〈/em〉 estimates than the MP-D method.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 353〈/p〉 〈p〉Author(s): Thiago Leite de Alencar, Arilene Franklin Chaves, Alcione Guimarães Freire, Ícaro Vasconcelos do Nascimento, Alexandre dos Santos Queiroz, Jaedson Cláudio Anunciato Mota〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Field capacity (FC) is one of the most cited soil physical parameters and is relevant for the management of agricultural systems. In the search for alternatives to the estimation of FC, several researchers have proposed methods based on dynamic and static criteria. Evaluating these methods within a range of soil textural classes is important for prospects of their uses with higher water use efficiency. Based on the hypothesis that FC for a certain soil textural class is exclusively associated with an equivalent pore diameter, 〈em〉D〈/em〉-〈em〉threshold〈/em〉, which separates structural and textural porosity, and that textural pores define the FC conditions, this study aimed to: 1) estimate the equivalent pore diameter (〈em〉D〈/em〉-〈em〉threshold〈/em〉) which defines FC in each soil textural class in situ and, with the change of density, from the alterations in its water characteristic curve - WCC; 2) estimate the water content at FC in each soil textural class in situ and, with the change of density, from the alterations in its WCC. To obtain the water content corresponding to FC in situ, instantaneous profile-type experiments were conducted in five soil textural classes. To estimate FC and 〈em〉D〈/em〉-〈em〉threshold〈/em〉 based on the change in pore volume (CPV), soil water characteristic curves were used considering two situations: before and after compaction. Correlation and regression analyses were carried out between 〈em〉D〈/em〉-〈em〉threshold〈/em〉 and sand percentage, between water content at FC and the fitting parameters α and 〈em〉n〈/em〉 of the model of van Genuchten (1980), and between the value of the tangent at the inflection point of the soil WCC and the parameter α. By comparing 〈em〉D〈/em〉-〈em〉threshold〈/em〉 values obtained by the field and CPV methods, it was possible to observe that for the range of textural classes analyzed, in general, 〈em〉D〈/em〉-〈em〉threshold〈/em〉 values obtained by CPV were different from those obtained in situ. Therefore, the methodological procedure CPV does not represent the actual 〈em〉D〈/em〉-〈em〉threshold〈/em〉 of the FC found under field conditions. The values of water content corresponding to FC obtained by the CPV protocol are not due to the physical aspect conceived in the method's proposal. Thus, since these values were not due to the 〈em〉D〈/em〉-〈em〉threshold〈/em〉, this protocol cannot be indicated because it became evident that there was no clear cause-effect relationship. It was concluded that: 1) the principle of the method of estimating FC must be consistent with processes occurring in the soil. Since FC is dependent on soil processes, and associated with a drainage rate, there is no good reason why the CPV method correctly estimates the attribute; 2) the water content at FC in a certain soil textural class is not exclusively associated with only one equivalent pore diameter, 〈em〉D〈/em〉-〈em〉threshold〈/em〉, so the hypothesis assumed in the study has not been confirmed; and 3) protocols based on soil water dynamics should preferentially be used to estimate FC, to the detriment of methods based on static criteria.〈/p〉〈/div〉 〈/div〉

Description: There is a growing body of research that recognizes the potentials of biochar application in agricultural production systems. However, little is known about the effects of biochar, especially hydrochar, on production of containerized seedlings under nursery conditions. This study aimed to test the effects of hydrochar application on growth, quality, nutrient and heavy metal contents, and mycorrhizal association of containerized pine seedlings. The hydrochar used in this study was produced through hydrothermal carbonization of paper mill biosludge at 200 °C. Two forms of hydrochar (powder and pellet) were mixed with peat at ratios of 10% and 20% (v/v) under three levels of applied commercial fertilizer (nil, half and full rates). Application of hydrochar had positive or neutral effects on shoot biomass and stem diameter compared with control seedlings (without hydrochar) under tested fertilizer levels. Analysis of the natural logarithmic response ratios (LnRR) of quality index and nutrient and heavy metal uptake revealed that application of 20% (v/v) hydrochar powder or pellet with 50% fertilizer resulted in same quality pine seedlings with similar heavy metal (Cu, Ni, Pb, Zn and Cr) and nutrient (P, K, Ca and Mg) contents as untreated seedlings supplied with 100% fertilizer. Colonization percentage by ectomycorrhizae significantly increased when either forms of hydrochar were applied at a rate of 20% under unfertilized condition. The results of this study implied that application of proper rates of hydrochar from biosludge with adjusted levels of liquid fertilizer may reduce fertilizer requirements in pine nurseries.

Description: The tank cascade system (TCS) has been used for over 2000 years for water management in Sri Lanka. Since surface water is limited in the dry zone of Sri Lanka, agricultural production, especially of upland crops, relies on groundwater for irrigation. We sampled 29 wells in the Ulagalla cascade, a prominent TCS near Anuradhapura city in the dry zone of Sri Lanka, in Yala (dry) and Maha (wet) seasons, the two main cropping seasons in Sri Lanka. We evaluated the suitability of groundwater for irrigation using the analytic hierarchy process and geographical information system. Water quality did not vary notably between seasons. However, it deteriorated with the onset of high intensity heavy rain, especially during the Maha season. A water quality zoning map indicated that groundwater in 4% and 96% of the study area is suitable and moderately suitable for irrigation, respectively. Irrigation water quality in tank cascade landscapes and similar environments can be assessed using this methodology and our results.

Description: Soils in tropical croplands are becoming degraded because of soil carbon (C) depletion. Local farmers in South India use a specific management of traditional cultivation, i.e., broadcast seeding. However, for sustainable C management, there is no quantitative data on the CO2 flux under this management. Our objectives were to (1) estimate the annual CO2 flux, and (2) evaluate the effect of traditional cultivation management (seeding rate) on the CO2 flux. Our field experiment was conducted in South India, from 2015 to 2017, including two cultivation periods with four cultivation management treatments (traditional cultivation management plot (T), fixed density plot (FD), no thinning plot (NT), and bare plot (B)). The seeding rate in the FD plot was ca. 50% of the T plot. We applied 1.1 Mg C ha−1 farmyard manure just before the experiment as a C input. We found that broadcasting, thinning, and cultivation increased soil moisture, while the CO2 efflux rate showed no significant difference between treatments throughout the experimental period. This indicates that cultivation management did not affect the CO2 flux. The total CO2 fluxes for two years were estimated at 2.2–2.7 Mg C ha−1. Our results indicate that it is necessary to apply larger or more frequent C inputs to prevent C depletion.

Description: The rye (Secale cereale L.) 5R chromosome contains some elite genes that can be used to improve wheat cultivars. In this study, a set of 5RKu dissection lines was obtained, and 111 new PCR-based and 5RKu-specific markers were developed using the specific length amplified fragment sequencing (SLAF-seq) method. The 111 markers were combined with the 52 5RKu-specific markers previously reported, and 65 S. cereale Lo7 scaffolds were physically mapped to six regions of the 5RKu chromosome using the 5RKu dissection lines. Additionally, the 5RLKu arm carried stripe rust resistance gene(s) and it was located to the region L2, the same region where 22 5RKu-specific markers and 11 S. cereale Lo7 scaffolds were mapped. The stripe rust resistance gene(s) located in the 5RLKu arm might be new one(s) because its source and location are different from the previously reported ones, and it enriches the resistance source of stripe rust for wheat breeding programs. The markers and the S. cereale Lo7 scaffolds that were mapped to the six regions of the 5RKu chromosome can facilitate the utilization of elite genes on the 5R chromosome in the improvement of wheat cultivars.

Description: Assessing and prescribing fertilizer use is critical to profitable and sustainable coffee production, and this is becoming a priority concern for the Robusta coffee industry. In this study, annual survey data of 798 farms across selected Robusta coffee-producing provinces in Vietnam and Indonesia between 2008 and 2017 were used to comparatively assess the fertilizer management strategies in these countries. Specifically, we aimed to characterize fertilizer use patterns in the key coffee-growing provinces and discuss the potential for improving nutrient management practices. Four types of chemical (NPK, super phosphate, potassium chloride and urea) and two of natural (compost and lime) fertilizers were routinely used in Vietnam. In Indonesia, NPK and urea were supplemented only with compost. Farmers in Vietnam applied unbalanced quantities of chemical fertilizers (i.e., higher rates than recommended) and at a constant rate between years whereas Indonesian farmers applied well below the recommended rates because of poor accessibility and financial support. The overuse of chemical fertilizers in Vietnam threatens the sustainability of Robusta coffee farming. Nevertheless, there is a potential for improvement in both countries in terms of nutrient management and sustainability of Robusta coffee production by adopting the best local fertilizer management practices.

Description: Perennial ryegrass (Lolium perenne L.) is one of the most important forage grass species in temperate regions of the world, but it is prone to having poor persistence due to the incidence of abiotic and biotic stresses. This creates a challenge for livestock producers to use their agricultural lands more productively and intensively within sustainable limits. Breeding perennial ryegrass cultivars that are both productive and persistent is a target of forage breeding programs and will allow farmers to select appropriate cultivars to deliver the highest profitability over the lifetime of a sward. Conventional methods for the estimation of pasture persistence depend on manual ground cover estimation or counting the number of surviving plants or tillers in a given area. Those methods are subjective, time-consuming and/or labour intensive. This study aimed to develop a phenomic method to evaluate the persistence of perennial ryegrass cultivars in field plots. Data acquisition was conducted three years after sowing to estimate the persistence of perennial ryegrass using high-resolution aerial-based multispectral and ground-based red, green and blue(RGB) sensors, and subsequent image analysis. There was a strong positive relationship between manual ground cover and sensor-based ground cover estimates (p 〈 0.001). Although the manual plant count was positively correlated with sensor-based ground cover (p 〈 0.001) intra-plot plant size variation influenced the strength of this relationship. We conclude that object-based ground cover estimation is most suitable for use in large-scale breeding programs due to its higher accuracy, efficiency and repeatability. With further development, this technique could be used to assess temporal changes of perennial ryegrass persistence in experimental studies and on a farm scale.

Description: High input costs combined with multiple management and material inputs have threatened cotton productivity. We hypothesize that this problem can be addressed by a single fertilization at flowering with late sowing in a moderately populated plant stand. Field experiments were conducted to evaluate the cotton biomass accumulation, phosphorus dynamics, and fiber quality under three planting densities (low, 3 × 104; moderate, 6 × 104; and dense, 9 × 104 ha−1) and two cultivars (Zhongmian-16 and J-4B). High planting density had 6.2 and 12.6% larger stems and fruiting nodes m−2, while low density produced a 37.5 and 59.4% maximum height node ratio. Moderate density produced 26.4–15.5%, 24.7–12.6%, and 10.5–13.6% higher biomass accumulation rate at the peak bloom, boll set, and plant removal stages over low and high density in both years, respectively. J-4B produced a higher reproductive organs biomass yield when compared with Zhongmian-16 in both years. This higher biomass formation was due to both the higher average (0.8 VT kg·ha−1·d−1) and maximum (1.0 VM kg·ha−1·d−1) reproductive organ phosphorus uptake, respectively. Plants with low density had 5.3–18.5%, 9.5–15%, and 7.8–12.8% greater length, strength, and micronaire values over moderate and dense plants, respectively. Conclusively, moderate density with J-4B is a promising option for improved biomass, phosphorus acquisition, and fiber quality under a short season.

Description: Three rust diseases namely; stem rust caused by Puccinia graminis f. sp. tritici (Pgt), leaf rust caused by Puccinia triticina (Pt), and stripe rust caused by Puccinia striiformis f. sp. tritici (Pst), are the most common fungal diseases of wheat (Triticum aestivum L.) and cause significant yield losses worldwide including Australia. Recently characterized stripe rust resistance genes Yr51 and Yr57 are effective against pre- and post-2002 Pst pathotypes in Australia. Similarly, stem rust resistance genes Sr22, Sr26, and Sr50 are effective against the Pgt pathotype TTKSK (Ug99) and its derivatives in addition to commercially important Australian pathotypes. Effectiveness of these genes make them good candidates for combining with known pleiotropic adult plant resistance (PAPR) genes to achieve durable resistance against three rust pathogens. This study was planned to transfer rust resistance genes Yr51, Yr57, Sr22, Sr26, and Sr50 into two Australian (Gladius and Livingston) and two Indian (PBW550 and DBW17) wheat cultivars through marker assisted selection (MAS). These cultivars also carry other rust resistance genes: Gladius carries Lr37/Yr17/Sr38 and Sr24/Lr24; Livingston carries Lr34/Yr18/Sr57, Lr37/Yr17/Sr38, and Sr2; PBW550 and DBW17 carry Lr34/Yr18/Sr57 and Lr26/Yr9/Sr31. Donor sources of Yr51 (AUS91456), Yr57 (AUS91463), Sr22 (Sr22/3*K441), Sr26 (Sr26 WA1), and Sr50 (Dra-1/Chinese Spring ph1b/2/3* Gabo) were crossed with each of the recurrent parents to produce backcross progenies. Markers linked to Yr51 (sun104), Yr57 (gwm389 and BS00062676), Sr22 (cssu22), Sr26 (Sr26#43), and Sr50 (Sr50-5p-F3, R2) were used for their MAS and markers csLV34 (Lr34/Yr18/Sr57), VENTRIUP-LN2 (Lr37/Yr17/Sr38), Sr24#12 (Sr24/Lr24), and csSr2 (Sr2) were used to select genes present in recurrent parents. Progenies of selected individuals were grown and selected under field conditions for plant type and adult plant rust responses. Final selections were genotyped with the relevant markers. Backcross derivatives of these genes were distributed to breeding companies for use as resistance donors.

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 353〈/p〉 〈p〉Author(s): Yanan Huang, Jaivime Evaristo, Zhi Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Interpretation of groundwater recharge mechanisms is problematic because of the muted instantaneous response of subsurface water to rainfall and limited recharge rates, particularly in semi-arid environments with deep loess deposits. Here we identify the possible groundwater recharge mechanisms in 200-m thick loess deposits with unsaturated zone thickness of over 40 m. We collected soil samples up to 15 m deep under four land use types (one grassland and three apple orchards with stand ages 15, 24 and 30 years old), and used three-year precipitation and groundwater samples to determine the contents of stable water isotopes, chloride, and tritium. Our overarching goal is to determine the relative importance of piston and preferential flow in groundwater recharge using multiple tracers and quantify the effects of land use change on groundwater recharge. We find that while both piston and preferential flows are important in groundwater recharge, the unsaturated and saturated zones have yet to come to hydraulic equilibrium. This suggests different groundwater recharge mechanisms: tracers in the unsaturated zone suggest piston flow, while the detectable tritium in the saturated zone implies preferential flow. Recharge rates in the unsaturated zones range between 23 and 82 mm year〈sup〉−1〈/sup〉, accounting for 4%–14% of mean annual precipitation, and increasing with depth presumably because of land use and/or climatic conditions. Total recharge rate in the saturated zone is 112.6 ± 44.1 mm year〈sup〉−1〈/sup〉, accounting for 19 ± 9% of mean annual precipitation. Overall, our study finds that piston flow contributes more to total recharge (53%–69%) than does preferential flow. Nevertheless, piston flow may become less important because of land use change (farmland to apple orchard conversion). Our findings have implications for the need to strike a delicate balance between the economic gains from afforestation and the possible risks to groundwater supply sustainability.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 353〈/p〉 〈p〉Author(s): Lei Deng, Changhui Peng, Chunbo Huang, Kaibo Wang, Qiuyu Liu, Yulin Liu, Xuying Hai, Zhouping Shangguan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil extracellular enzymatic activity (EEA) stoichiometry could reflect the biogeochemical equilibrium between the metabolic requirements of microbial communities and environmental nutrients availability. However, the drivers of soil microbial metabolic limitation (SMML) changes remain poorly understood following vegetation restoration. We compared sites along a vegetation restoration chronosequence over a 30-year period on the Loess Plateau, China, and measured the potential activities of two C-acquiring enzymes (β-1,4-glucosidase (BG) and β-〈span〉d〈/span〉-cellobiosidase (CBH)), two N-acquiring enzymes (β-1,4-〈em〉N〈/em〉-acetylglucosaminidase (NAG) and 〈span〉l〈/span〉-leucine aminopeptidase (LAP)), and one organic-P-acquiring enzyme (alkaline phosphatase (AP)), to quantify and compare the variations in metabolic limitations for soil microorganisms using EEA stoichiometry. The results showed constant microbial P limitation, but not N limitation, and an open downward “unimodal” trend in microbial C limitation; however, the microbial P limitation displayed exactly the opposite trend during vegetation restoration. Restoration age and properties of plant, soil, and microorganisms contributed to 82.9% of microbial C limitation and 84.6% of microbial P limitation, with soil presenting the highest relative effects of 76.1% and 59.6% on microbial C and P limitations, respectively. Plant productivity and species diversity decreased microbial C limitation owing to increasing plant C inputs, but increased microbial P limitation owing to plant nutrients competition with soil microorganisms. When the fungi:bacteria ratio in the soil increased, the SMML increased. Vegetation restoration increased the soil nutrients content and reduced SMML, and a decrease in the soil water content increased microbial P limitation. Thus, the effects of long-term vegetation restoration on SMML were the result of combined influences of plants, soil, and microorganisms.〈/p〉〈/div〉 〈/div〉

Description: Reducing soil tillage can lead to many benefits, but this practice often increases weed abundance and thus the need for herbicides, especially during the transition phase from inversion tillage to non-inversion tillage. We evaluated if subsidiary crops (SCs, e.g., cover crops) can mitigate the effects of non-inversion tillage on weed abundance. Two-year experiments studying SC use, tillage intensity, and nitrogen (N) fertilization level were carried out twice at six sites throughout northern and central Europe. SCs significantly reduced weed cover throughout the intercrop period (−55% to −1% depending on site), but only slightly during the main crops. Overall weed abundance and weed biomass were higher when using non-inversion tillage with SCs compared to inversion tillage without SCs. The effects differed due to site-specific weed pressure and management. With increasing weed pressure, the effect of SCs decreased, and the advantage of inversion over non-inversion tillage increased. N fertilization level did not affect weed abundance. The results suggest that SCs can contribute by controlling weeds but cannot fully compensate for reduced weed control of non-inversion tillage in the transition phase. Using non-inversion tillage together with SCs is primarily recommended in low weed pressure environments.

Description: Chamomile (Matricaria chamomilla L.) is a well-known medicinal plant species in which the products requested from the market are those that are derived from the organic system. The study was conducted to assess the allelopathic effects, as natural herbicides, of two essential oils extracted from oregano (Origanum vulgare L.) and rosemary (Rosmarimum officinalis L.), with the objective of exploring the possibility of their utilization for future weed management. A field experiment was conducted over two seasons, when the infestation of 15 different weed species was detected. Each essential oil was applied at two different concentrations (50% diluted and undiluted), three times during the chamomile crop under an organic farm system. The results demonstrated that the germination of different weed species was affected differently by the type of essential oils and especially by their concentrations. The undiluted oils inhibited most of the germination of several weed species, highlighting a significantly higher percentage of Weed Control Efficiency (WCE) and suggesting the potential to be used as bio-herbicides. Bioherbicidal weed control methods could offer an advantage with respect to hand weeding, particularly from an economic point of view.

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 353〈/p〉 〈p〉Author(s): Cancan Zhao, Jie Zhao, Jianping Wu, Aimée T. Classen, Yanxia Li, Yiping Lou, Weixin Zhang, Xin Jing, Yuanhu Shao, Shenglei Fu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bamboos are widespread in the subtropics and tropics. They grow quickly, and are therefore important substitute for timber. Bamboo forest management and cultivation often include removing competitive trees; thus these shifts in forest composition should cascade to impact soil communities and the processes they mediate. Using a long-term (12 year) bamboo forest management study, we determined the impact of bamboo forest management on soil microbial and nematode community composition through time (2008–2010). Surprisingly, we found that conversion from a mixed and relatively diverse bamboo forest to a pure bamboo forest did not affect bamboo biomass. However, the soil fungal:bacterial ratio, nematode diversity index, and fungivores:bacterivores all declined within and across years. Taken together, our results suggest that conversion from mixed to pure bamboo forest can cause a switch from the fungal-based to the bacterial-based energy channel, i.e., accelerate the energy flow and reduce the stability of the soil ecosystem. The findings suggest that managing for a mixed bamboo forest may increase forest diversity and health overtime.〈/p〉〈/div〉 〈/div〉

Description: The establishment and application of a spectral library is a critical step in the standardization and automation of remote sensing interpretation and mapping. Currently, most spectral libraries are designed to support the classification of land cover types, whereas few are dedicated to agricultural remote sensing monitoring. Here, we gathered spectral observation data on plants in multiple experimental scenarios into a spectral database to investigate methods for crop classification (16 crop species) and status monitoring (tea plant and rice growth). We proposed a set of screening methods for spectral features related to plant classification and status monitoring (band reflectance, vegetation index, spectral differentiation, spectral continuum characteristics) that are based on ISODATA and JM distance. Next, we investigated the performance of different machine learning classifiers in the spectral library application, including K-nearest neighbor (KNN), Random Forest (RF), and a genetic algorithm coupled with a support vector machine (GA-SVM). The optimal combination of spectral features and the classifier with the highest classification accuracy were selected for crop classification and status monitoring scenarios. The GA-SVM classifier performed the best, which produced an accuracy of OAA = 0.94, Kappa = 0.93 for crop classification in a complex scenario (crops mixed with 71 non-crop plant species), and promising accuracies for tea plant growth monitoring (OAA = 0.98, Kappa = 0.97) and rice growth stage monitoring (OAA = 0.92, Kappa = 0.90). Therefore, the establishment of a plant spectral library combined with relevant feature extraction and a classification algorithm effectively supports agricultural monitoring by remote sensing.

Description: 〈p〉Publication date: 1 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 355〈/p〉 〈p〉Author(s): Alexandre M.J-C. Wadoux, Dick J. Brus, Gerard B.M. Heuvelink〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Machine learning techniques are widely employed to generate digital soil maps. The map accuracy is partly determined by the number and spatial locations of the measurements used to calibrate the machine learning model. However, determining the optimal sampling design for mapping with machine learning techniques has not yet been considered in detail in digital soil mapping studies. In this paper, we investigate sampling design optimization for soil mapping with random forest. A design is optimized using spatial simulated annealing by minimizing the mean squared prediction error (MSE). We applied this approach to mapping soil organic carbon for a part of Europe using subsamples of the LUCAS dataset. The optimized subsamples are used as input for the random forest machine learning model, using a large set of readily available environmental data as covariates. We also predicted the same soil property using subsamples selected by simple random sampling, conditioned Latin Hypercube sampling (cLHS), spatial coverage sampling and feature space coverage sampling. Distributions of the estimated population MSEs are obtained through repeated random splitting of the LUCAS dataset, serving as the population of interest, into subsets used for validation, testing and selection of calibration samples, and repeated selection of calibration samples with the various sampling designs. The differences between the medians of the MSE distributions were tested for significance using the non-parametric Mann-Whitney test. The process was repeated for different sample sizes. We also analyzed the spread of the optimized designs in both geographic and feature space to reveal their characteristics. Results show that optimization of the sampling design by minimizing the MSE is worthwhile for small sample sizes. However, an important disadvantage of sampling design optimization using MSE is that it requires known values of the soil property at all locations and as a consequence is only feasible for subsampling an existing dataset. For larger sample sizes, the effect of using an MSE optimized design diminishes. In this case, we recommend to use a sample spread uniformly in the feature (i.e. covariate) space of the most important random forest covariates. The results also show that for our case study, cLHS sampling performs worse than the other sampling designs for mapping with random forest. We stress that comparison of sampling designs for calibration by splitting the data just once is very sensitive to the data split that one happens to use if the validation set is small.〈/p〉〈/div〉

Description: Crop models are useful tools to evaluate the effects of agricultural management on ecosystem services. However, before they can be applied with confidence, it is important to calibrate and validate crop models in the region of interest. In this study, the Environmental Policy Integrated Climate (EPIC) model was evaluated for its potential to simulate maize yield using limited data from field trials on two maize cultivars. Two independent fields at the Cradock Research Farm were used, one for calibration and one for validation. Before calibration, mean simulated yield was 8 t ha−1 while mean observed yield was 11.26 t ha−1. Model calibration improved mean simulated yield to 11.23 t ha−1 with a coefficient of determination, (r2) = 0.76 and a model efficiency (NSE) = 0.56. Validation with grain yield was satisfactory with r2 = 0.85 and NSE = 0.61. Calibration of potential heat units (PHUs) and soil-carbon related parameters improved model simulations. Although the study only used grain yield to calibrate and evaluate the model, results show that the calibrated model can provide reasonably accurate simulations. It can be concluded that limited data sets from field trials on maize can be used to calibrate the EPIC model when comprehensive experimental data are not available.

Description: Lemon processing generates thousands of tons of residues that can be preserved as flours by thermal treatment to obtain phenolic compounds with beneficial bioactivities. In this study, the effect of different drying temperatures (40, 50, 60, 70, 80, 90, 100 and 110 °C) on the Total Phenolic Content (TPC), antioxidant and antimicrobial activities of phenolic compounds present in Citrus. lemon (L.) Burn f waste was determined. Identification and quantification of phenolic compounds were also performed by UPLC-PDA and UPLC-ESI-MS analysis. Eriocitrin (19.79–27.29 mg g−1 DW) and hesperidin (7.63–9.10 mg g−1 DW) were detected as the major phenolic compounds in the flours by UPLC-PDA and confirmed by UPLC-ESI-MS. Antimicrobial activity determined by Minimum Inhibitory Concentration (MIC) against Salmonella typhimurium, Escherichia coli and Staphylococcus aureus was observed. Accordingly, a stable functional flour as a source of bioactive phenolic compounds obtained from lemon residues at 50 °C may be produced as a value-added product useful in various industrial sectors.

Description: 〈p〉Publication date: 15 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 356〈/p〉 〈p〉Author(s): Mark A. Chappell, Jennifer M. Seiter, Haley M. West, Lesley F. Miller, Maria E. Negrete, Joshua J. LeMonte, Beth E. Porter, Cynthia L. Price, Matthew A. Middleton〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil heterogeneity is a major contributor to the uncertainty in predicting the environmental fate of data-scare contaminants. For this paper, we focused on research designed to predict the soil environmental fate of the new munition compound, called 2,4-dinitroanisole (DNAN) -a compound increasingly employed by the U.S. and international militaries in the next-generation, insensitive explosive formulations. Here, we employed multivariate statistical correlation models to predict DNAN sorption among different soil “types” seeking to reduce the uncertainty common in all contaminant sorption models by using soil taxonomic designation as a calibrant. We collected composite soils classified under the Ultisols taxonomic Order in the U.S. National Resource Conservation Service soil classification system and quantified their properties via physical and chemical characterizations. Using multivariate statistical modeling modified for compositional data analysis (CoDa), we developed quantitative analogies of the Ultisols by partitioning the characterization data up into four different compositions: Water-extracted, Mehlich-III (referring to the weak acid) extracted, particle-size distribution, and solid-phase carbon‑nitrogen‑sulfur compositions. DNAN sorption was measured in batch soil suspensions and distribution coefficients (K〈sub〉D〈/sub〉) were calculated using linear regression modeling. Prediction models testing the correlation of the DNAN K〈sub〉D〈/sub〉 values to the centered logratio -transformed compositions were calculated using CoDa-modified multilinear regression. Results showed that DNAN sorption was only predictable by dissolved organic carbon, pH, and the exchangeable cations Ca and K within the water-extracted composition. Analogies for DNAN sorption were the most discriminating at the Suborder level because of the inherent ambiguity in the Hapludults class at the Great Group level.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0016706119303842-ga1.jpg" width="375" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 356〈/p〉 〈p〉Author(s): Jörg Prietzel, Martin Wiesmeier〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A correct quantification of soil surface and soil organic carbon (SOC) stocks is crucial for the evaluation of important soil functions, including atmospheric C sequestration. At present, soil science lacks (i) a clear definition of soil depth, (ii) consented procedures for soil sampling, as well as (iii) adequate awareness concerning pitfalls and caveats associated with quantification of soil surface area and large-scale SOC stocks in mountainous, complex landscapes. Traditional SOC stock quantification in these landscapes often did not adequately address site-specific geomorphological conditions and thus yielded incorrect results due to combination of incompatible methods for soil depth assessment, soil profile or core sampling, and soil surface area calculation. In our paper, we suggest unequivocal definitions of soil depth, horizon thickness, and SOC density, which can be applied for soils in sloping as well as flat terrain. Moreover, we quantify and discuss potential SOC (and other soil nutrient) stock assessment errors in mountainous regions, using the German Alps as case study. We present a protocol to ensure an unbiased quantification of soil surface area, as well as SOC or nutrient element stocks in mountainous landscapes. Taking into account the considerable area of sloping terrain on the global scale, and particularly in mountainous countries (e.g. Switzerland, Austria, Andes Countries, Nepal, Japan), our publication will contribute to a more accurate quantification of soil stocks of SOC and important nutrients as well as area-based C fluxes (e.g. CO〈sub〉2〈/sub〉 sequestration or release) or other surface-related biogeochemical fluxes.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0016706119308018-ga1.jpg" width="488" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 356〈/p〉 〈p〉Author(s): S.S. Paul, N.C. Coops, M.S. Johnson, M. Krzic, S.M. Smukler〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The performance of digital soil mapping (DSM) model is highly reliant on the intensity and spatial distribution of the input soil data points. Increasing the number of soil data points (i.e. samples) improves the accuracy of the prediction, but it also raises the sampling effort, including the time, money and labor required for field and laboratory analysis. Thus, optimizing the production of DSMs requires maximizing accuracy while minimizing cost. In this study, we evaluated a range of strategies for DSM of a farm field using high spatial resolution ancillary environmental data (e.g. unmanned aerial vehicle-UAV imagery) and compared sampling efforts of soil data generated from standard laboratory analysis (SLA) and mid-infrared spectroscopy (MIRS) at equivalent costs. We produced DSMs of a number of soil properties including sand, silt, clay, pH, salinity, organic matter, and total nitrogen. We employed Conditioned Latin Hypercube Sampling (cLHS) to generate a range of sampling efforts from the full SLA (〈em〉n〈/em〉 = 62) and MIRS (〈em〉n〈/em〉 = 308) datasets and contrasted the DSM outcomes modeled using kriging with external drift (KED). We found that the DSM outputs were most effective, in terms of accuracy and cost, at 50–60% of the full sampling effort. Although MIRS predictions of soil properties introduced a sizable amount of error, DSMs produced using the MIRS dataset were more accurate as compared to the outcomes of SLA datasets at equivalent sampling efforts. The prediction accuracy for DSMs varied across the soil properties with R〈sup〉2〈/sup〉 ranging from 0.82 (for sand) to 0.45 (for total nitrogen) at the optimum sampling effort. The outcomes of the study highlight that spatially optimized sampling efforts and the use of the MIRS technique substantially improve the cost efficiency and accuracy of kriging-based DSM models for predicting a range of field scale soil properties.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 356〈/p〉 〈p〉Author(s): Nader Shahabinejad, Majid Mahmoodabadi, Ahmad Jalalian, Elham Chavoshi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil particle size distribution (PSD) plays an important role in wind erosion studies and sediment transport modeling. Few studies have been done focusing on the susceptibility of different soil fractions to wind erosion under natural conditions. This study was performed to measure in-situ wind erosion rates using a portable wind tunnel facility on 60 undisturbed soils of arid to semiarid regions. The effects of primary (i.e. clay, silt, and sand particles) and 16 secondary (aggregate) size classes were attributed to wind erosion rates. Moreover, the boundaries between major fractions of the soils (i.e. micro-aggregates, meso-aggregates and macro-aggregates) were determined. The result showed that clay and silt particles and also surface rock fragment were inversely proportional to wind erosion rates as power functions, whereas sand content showed a positive exponential relationship. The size ranges of 〈53 μm, 53–300 μm and 〉300 μm were distinguished for the micro-aggregates, meso-aggregates, and macro-aggregates, respectively. The meso-aggregate fraction was proportional and the micro-aggregate and macro-aggregate fractions were inversely proportional to wind erosion rates. Furthermore, a narrower size range of 75–150 μm was detected as the most erodible soil fraction. The distribution of the primary particles in the major aggregate fractions was different, so that in the meso-aggregates, sand particles and in the micro-aggregates and macro-aggregates, silt and especially clay particles predominated. It is concluded that the presence of macro-aggregates (〉300 μm) associated with fine primary particles (clay) can significantly reduce wind erosion rate rather than the sandy soils containing weaker aggregates.〈/p〉〈/div〉 〈/div〉

Description: Fusarium Head Blight (FHB, scab) is a destructive fungal disease that causes extensive yield and quality losses in wheat and other small cereals. Biological control of FHB is considered to be an alternative disease management strategy that is environmentally benign, durable, and compatible with other control measures. In this study, to screen antagonistic bacteria with the potential to manage FHB, 113 endophytes were isolated from the stems, leaves, panicles, and roots of wheat. Among them, six strains appeared to effectively inhibit Fusarium graminearum growth and one isolate, XS-2, showed a highly antagonistic effect against FHB. An in vitro antagonistic test of XS-2 on wheat heads confirmed that XS-2 could suppress the disease severity of FHB. The 16S rDNA sequence analysis revealed that XS-2 is a strain of Bacillus amyloliquefaciens. Antagonistic spectrum analyses showed that XS-2 had antagonistic effects against two and four types of cotton and fruit tree pathogens, respectively. The fermentation condition assays showed that glucose and peptone are the most suitable nutrient sources for XS-2, and that the optimal pH value and temperature for fermentation were 7.4 and 28 °C, respectively. Our study indicates that XS-2 has a good antagonistic effect on FHB and lays a theoretical foundation for the application of the strain as a biological agent in the field to control FHB.

Description: 〈p〉Publication date: 1 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 355〈/p〉 〈p〉Author(s): A. Schomburg, D. Sebag, P. Turberg, E.P. Verrecchia, C. Guenat, P. Brunner, T. Adatte, R. Schlaepfer, R.C. Le Bayon〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil structure formation in alluvial soils is a fundamental process in near-natural floodplains. A stable soil structure is essential for many ecosystem services and helps to prevent river bank erosion. Plants and earthworms are successful soil engineering organisms that improve the soil structural stability through the incorporation of mineral and organic matter into soil aggregates. However, the heterogeneous succession of different textured mineral and buried organic matter layers could impede the development of a stable soil structure. Our study aims at improving the current understanding of soil structure formation and organic matter dynamics in near natural alluvial soils. We investigate the effects of soil engineering organisms, the composition, and the superimposition of different alluvial deposits on the structuration patterns, the aggregate stability, and organic matter dynamics in 〈em〉in vitro〈/em〉 soil columns, representing sediment deposition processes in alluvial soils. Two successions of three different deposits, silt–buried litter–sand, and the inverse, were set up in mesocosms and allocated to four different treatments, i.e. plants, earthworms, plants + earthworms, and a control. X-ray computed tomography was used to identify structuration patterns generated by ecosystem engineers, i.e. plant root galleries and earthworm tunnels. Organic matter dynamics in macro-aggregates were investigated by Rock-Eval pyrolysis. Plant roots only extended in the top layers, whereas earthworms preferentially selected the buried litter and the silt layers. Soil structural stability measured via water stable aggregates (%WSA) increased in the presence of plants and in aggregates recovered from the buried litter layer. Organic matter dynamics were controlled by a complex interplay between the type of engineer, the composition (silt, sand, buried litter) and the succession of the deposits in the mesocosm. Our results indicate that the progress and efficiency of soil structure formation in alluvial soils strongly depends on the textural sequences of alluvial deposits.〈/p〉〈/div〉 〈/div〉

Description: China has attained rice sufficiency with the increased use of nitrogen (N) fertilizer, but this has led to serious N pollution. China has the world’s highest use of N with the lowest N use efficiency (NUE). Including livestock production, China’s agriculture sector has surpassed industry as the greatest polluter of water. Using plastic film on raised-beds, combined with improved agronomic practices, can boost rice yield by 50% with 36% less N fertilizer use, 30% higher NUE, and stabilized the yield of 9.75 t ha−1. It also counters the effects of drought and low ambient temperature. A six-year study was conducted combining no-tillage, crop-residue mulch, and plastic cover, alternating organic rice and rapeseed production. All the treatments, fertilized with biogas slurry and rapeseed meal, gave rice yields of 7.0 to 10.7 t ha−1, well above China’s average of 6.5 t ha−1. In this time, soil organic matter increased from 1.6% to 4.2%. In the first four years, the combination of crop-residue mulch with plastic cover had a slightly higher yield than mulch alone. In the fifth and sixth years, the latter treatment surpassed the use of plastic cover with crop-residue mulch. Trials with a biodegradable film show that plastic pollution can be dealt with.

Description: The aim of the study was to determine the Actinobacteria structure in cultivated (C) versus non-cultivated (NC) soils divided into three groups (autogenic, hydrogenic, lithogenic) with consideration its formation process in order to assess the Actinobacteria sensitivity to agricultural soil use and soil genesis and to identify factors affecting their abundance. Sixteen C soil samples and sixteen NC samples serving as controls were taken for the study. Next generation sequencing (NGS) of the 16S rRNA metagenomic amplicons (Ion Torrent™ technology) and Denaturing Gradient Gel Electrophoresis (DGGE) were applied for precise determination of biodiversity. Generally, greater abundance of Actinobacteria in the NC soils relative to the C soils was found. Moreover, it was indicated that the actinobacterial diversity depended on both the soil genesis and the land use; however, this effect directly depended on the particular family and genera. Two factors: redox potential (Eh) and total carbon (TC) seemed to had a significant effect on the diversity of Actinobacteria. More precisely, Actinobacteria from the NC soils displayed a greater affinity for each other and were clearly influenced by Eh, whilst those from the C soils were mostly influenced by TC.

Description: 〈p〉Publication date: 1 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 355〈/p〉 〈p〉Author(s): F.J.T. van der Bom, T.I. McLaren, A.L. Doolette, J. Magid, E. Frossard, A. Oberson, L.S. Jensen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Data on the dynamics and fate of phosphorus (P) under low soil-test P (STP) conditions is essential for the development of cropping strategies with a high P use efficiency. This study examined the effects of long-term (20 years) mineral and organic fertiliser P applications on a P-depleted sandy loam soil in Denmark. The cycling of P was examined by use of P budgets (inputs-offtake), chemical P extractions, 〈sup〉33〈/sup〉P isotopic exchange kinetics (IEK), and solution 〈sup〉31〈/sup〉P nuclear magnetic resonance (NMR) spectroscopy on NaOH-EDTA extracts.〈/p〉 〈p〉Recovery of applied P in the topsoil was smaller for animal slurry P compared with mineral fertiliser P. The budgets suggest deeper soil layers play an important role for the cycling of P. Resin-extractable P (2 to 17 mg kg〈sup〉−1〈/sup〉), Olsen-P (7 to 16 mg kg〈sup〉−1〈/sup〉) and E〈sub〉1min〈/sub〉 (1 to 6 mg kg〈sup〉−1〈/sup〉) were correlated with the P budgets. Between 63 and 77% of total inorganic P was not exchangeable in a period of three months (E〈sub〉〉3months〈/sub〉), with the lowest value observed in no-P treatment N〈sub〉1〈/sub〉K〈sub〉1〈/sub〉. The data show that a redistribution of exchangeable P had taken place under the influence of a strongly negative P budget. Microbial P (6 to 18 mg kg〈sup〉−1〈/sup〉) increased under animal slurry inputs compared with mineral fertiliser applications (〈em〉p〈/em〉 〈 0.05). All soils were dominated by phosphomonoesters and orthophosphate (98 to 99% of the NMR signal). Concentrations of orthophosphate (86 to 135 mg kg〈sup〉−1〈/sup〉) varied significantly between treatments (〈em〉p〈/em〉 〈 0.01), whereas forms of organic P remained largely unchanged.〈/p〉 〈p〉The results demonstrate that P applications increased the amount of P that is potentially available for plants, irrespective of input form. Nevertheless, most P applied in excess of crop uptake resulted in an increase of the amount of P that is slowly exchangeable. Under low soil test P conditions such as in the current trial, fertiliser P applied in excess of plant demand that accumulates in soil would thus only be partially available for crops in subsequent years. On the other hand the data suggests that soil P reserves may be utilised for crop growth, but at the low soil P intensity plant access to P will have to be managed carefully.〈/p〉 〈/div〉 〈/div〉

Description: Adoption of no-till systems in Eastern Washington has been slow due to the difficulty of managing wheat (Triticum aestivum L.) straw residue and the unknown decomposition potential of cultivars. We hypothesize that by analyzing wheat straw with near-infrared spectroscopy (NIRS), calibration models can be developed to accurately predict fiber and chemical constituents of wheat, determining straw decomposition potential. Straw from a panel of 480 soft winter wheat cultivars adapted to the Pacific Northwest are analyzed for neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), cellulose, hemicellulose, carbon (C), and nitrogen (N). Using modified partial least squares regression and cross validation techniques, specific environment and broad-based NIRS models are calibrated and predictive ability is validated. R2cal values from broad models are better than the specific models, and are 0.85 (NDF), 0.86 (ADF), 0.65 (ADL), 0.88 (cellulose), 0.42 (hemicellulose), 0.67 (C), and 0.73 (N). The corresponding SEP values are 1.68% (NDF), 1.54% (ADF), 0.62% (ADL), 1.14% (cellulose), 1.11% (hemicellulose), 1.23% (C), and 0.06% (N). A Finch × Eltan breeding population is used to further validate models and prediction accuracies for variety selection within a breeding program scenario. The broad NIRS models prove useful for estimating high and low ranges of NDF, ADF, and cellulose in wheat cultivars which translate into characteristics of slow and fast decomposition potential.

Description: The inclusion of species with allelopathic activity in crop rotation systems may have benefits for crop management such as weed control, but less is understood about their wider impacts on succeeding crops. The main objective of this study was to investigate the effects of two allelopathic species (spearmint and peppermint) on growth, physiological characteristics, and yield of a following maize crop. Thus, field experiments were carried out at two sites, according to a randomized complete block design, while the examined treatments were: (a) fallow–fallow–maize crop rotation system (FFM), (b) spearmint–spearmint–maize crop rotation system (SSM), and (c) peppermint–peppermint–maize crop rotation system (PPM). Our results indicated that the inclusion of spearmint or peppermint in crop rotation systems negatively affect the growth of maize plants. The highest plant height was recorded for FFM rotation system where no allelopathic species were used. At both sites and for four sampling dates, the aboveground dry biomass was also affected by the implemented crop rotation system. In particular, dry biomass was significantly lower in the PPM and SSM crop rotation systems comparing to the FFM system, whereas there were no significant differences between these two crop rotation systems. Similar to the maize biomass, the highest values of photosynthetic rate, stomatal conductance, and relative chlorophyll content were observed for the FFM rotation system. Additionally, differences in grain yield were observed among the tested crop rotation systems. Grain yield ranged from 10,200 to 13,346 kg ha−1 and from 11,773 to 14,106 kg ha−1 at site A and B, respectively, while it was reduced by 16.54–23.58% and 12.16–17.83% in the SSP and PPM rotation systems comparing to the FFM system. In conclusion, our results indicate that the inclusion of peppermint or spearmint in crop rotation may inhibit plant growth and reduce grain yield of maize as successive crop, an effect that could be attributed to the allelopathic activity of spearmint and peppermint.

Description: The Midwestern U.S. landscape is one of the most highly altered and intensively managed ecosystems in the country. The predominant crops grown are maize (Zea mays L.) and soybean [Glycine max (L.) Merr]. They are typically grown as monocrops in a simple yearly rotation or with multiple years of maize (2 to 3) followed by a single year of soybean. This system is highly productive because the crops and management systems have been well adapted to the regional growing conditions through substantial public and private investment. Furthermore, markets and supporting infrastructure are highly developed for both crops. As maize and soybean production have intensified, a number of concerns have arisen due to the unintended environmental impacts on the ecosystem. Many areas across the Midwest are experiencing negative impacts on water quality, soil degradation, and increased flood risk due to changes in regional hydrology. The water quality impacts extend even further downstream. We propose the development of an innovative system for growing maize and soybean with perennial groundcover to recover ecosystem services historically provided naturally by predominantly perennial native plant communities. Reincorporating perennial plants into annual cropping systems has the potential of restoring ecosystem services without negatively impacting grain crop production and offers the prospect of increasing grain crop productivity through improving the biological functioning of the system.

Description: Rice blast is a serious fungal disease of rice (Oryza sativa L.) that is threatening global food security. It has been extensively studied due to the importance of rice production and consumption, and because of its vast distribution and destructiveness across the world. Rice blast, caused by Pyricularia oryzae Cavara 1892 (A), can infect aboveground tissues of rice plants at any growth stage and cause total crop failure. The pathogen produces lesions on leaves (leaf blast), leaf collars (collar blast), culms, culm nodes, panicle neck nodes (neck rot), and panicles (panicle blast), which vary in color and shape depending on varietal resistance, environmental conditions, and age. Understanding how rice blast is affected by environmental conditions at the cellular and genetic level will provide critical insight into incidence of the disease in future climates for effective decision-making and management. Integrative strategies are required for successful control of rice blast, including chemical use, biocontrol, selection of advanced breeding lines and cultivars with resistance genes, investigating genetic diversity and virulence of the pathogen, forecasting and mapping distribution of the disease and pathogen races, and examining the role of wild rice and weeds in rice blast epidemics. These tactics should be integrated with agronomic practices including the removal of crop residues to decrease pathogen survival, crop and land rotations, avoiding broadcast planting and double cropping, water management, and removal of yield-limiting factors for rice production. Such an approach, where chemical use is based on crop injury and estimated yield and economic losses, is fundamental for the sustainable control of rice blast to improve rice production for global food security.

Description: A study was conducted in an irrigated arid agroecosystem in southwestern USA, to compare two conservation tillage systems (strip tillage (ST) and no-tillage (NT)) to conventional, plow-based tillage (PT) system. Corn silage (Zea mays L.) was planted in this trial. Growth parameters (plant population and height) of corn silage were measured during the season and yield was evaluated at harvest. Soil physical measurements assessed included mean weight diameter of dry aggregates, wet aggregate stability, and penetrometer resistance. While soil biological measurements included total microbial biomass, diversity index (DI), total bacteria biomass, total fungi biomass (TFB), arbuscular mycorrhizae fungi (AMF), and total saprophytes. Results showed that plant population and silage yield at 65% moisture content were not significant with tillage during both trial years. Soil physical parameters were mostly not significant with tillage, while three out of the six biological measurements (DI, TF, and AM) were significant with tillage at p ≤ 0.05. No-tillage had higher DI and TFB than the ST, but not different from PT, while AMF was significantly higher in PT than ST, but not different from NT. The study demonstrates that farmers in the study region can adopt conservation tillage without yield losses during the early years of transition.

Description: The frequency of drought periods influences the yield potential of crops under field conditions. The change in morphology and anatomy of plants has been tested during drought stress under controlled conditions but the change in physiological processes has not been adequately studied in separate studies but needs to be reviewed collectively. This review presents the responses of green peas, snap beans, tomatoes and sweet corn to water stress based on their stomatal behaviour, canopy temperature, chlorophyll fluorescence and the chlorophyll content of leaves. These stress markers can be used for screening the drought tolerance of genotypes, the irrigation schedules or prediction of yield.

Description: A combination of organic and conservation approaches have not been widely tested, neither considering agronomic implications nor the impacts on the environment. Focussing on the effect of agricultural practices on greenhouse gas (GHG) emissions from soil, the hypothesis of this research is that the organic conservation system (ORG+) may reduce emissions of N2O, CH4 and CO2 from soil, compared to an integrated farming system (INT) and an organic (ORG) system in a two-year irrigated vegetable crop rotation set up in 2014, in a Mediterranean environment. The crop rotation included: Savoy cabbage (Brassica oleracea var. sabauda L. cv. Famosa), spring lettuce (Lactuca sativa L. cv. Justine), fennel (Foeniculum vulgare Mill. cv. Montebianco) and summer lettuce (L. sativa cv. Ballerina). Fluxes from soil of N2O, CH4 and CO2 were measured from October 2014 to July 2016 with the flow-through non-steady state chamber technique using a mobile instrument equipped with high precision analysers. Both cumulative and daily N2O emissions were mainly lower in ORG+ than in INT and ORG. All the cropping systems acted as a sink of CH4, with no significant differences among treatments. The ORG and ORG+ systems accounted for higher cumulative and daily CO2 emissions than INT, maybe due to the stimulating effect on soil respiration of organic material (fertilizers/plant biomass) supplied in ORG and ORG+. Overall, the integration of conservation and organic agriculture showed a tendency for higher CO2 emissions and lower N2O emissions than the other treatments, without any clear results on its potential for mitigating GHG emissions from soil.

Description: Climate change is viewed as a cause in accelerating the rate of invasion by alien species in addition to the globalization of anthropogenic activities. Ecological niche modeling has become an instrument in predicting invasion from natural or invaded ranges to uninvaded ranges based on the presence records of organisms and environmental parameters. This study explored the changes in the distributions of globally noxious alien species (Aegratina adenophora, Ageratum conyzoides, Chromolaena odorata, Lantana camara, Mikania micrantha, and Parthenium hysterophorus) in Bhutan, to provide evidence that even a mountain environment is under the threat of invasion given the change in climatic conditions. With fairly high accuracy, the model results suggest that there will be a potential increase in the areas of invasion among most of the species, except Parthenium hysterophorus, which will experience a northerly shift and decline in distribution. The results also indicate changes in patterns of invasion, some becoming more concentrated toward a given direction, while others become more dispersed over time. This study provides a framework that can be used in the strategic control of the species, future detection surveys, and further research.

Description: Phenolic compounds in basil (Ocimum basilicum) plants grown under a controlled environment are reduced due to the absence of ultraviolet (UV) radiation and low photosynthetic photon flux density (PPFD). To characterize the optimal UV-B radiation dose and PPFD for enhancing the synthesis of phenolic compounds in basil plants without yield reduction, green and purple basil plants grown at two PPFDs, 160 and 224 μmol·m−2·s−1, were treated with five UV-B radiation doses including control, 1 h·d−1 for 2 days, 2 h·d−1 for 2 days, 1 h·d−1 for 5 days, and 2 h·d−1 for 5 days. Supplemental UV-B radiation suppressed plant growth and resulted in reduced plant yield, while high PPFD increased plant yield. Shoot fresh weight in green and purple basil plants was 12%–51% and 6%–44% lower, respectively, after UV-B treatments compared to control. Concentrations of anthocyanin, phenolics, and flavonoids in green basil leaves increased under all UV-B treatments by 9%–18%, 28%–126%, and 80%–169%, respectively, and the increase was greater under low PPFD compared to high PPFD. In purple basil plants, concentrations of phenolics and flavonoids increased after 2 h·d−1 UV-B treatments. Among all treatments, 1 h·d−1 for 2 days UV-B radiation under PPFD of 224 μmol·m−2·s−1 was the optimal condition for green basil production under a controlled environment.

Description: Auxin regulates diverse aspects of growth and development. Furthermore, polar auxin transport, which is mediated by the PIN-FORMED (PIN) and AUXIN1/LIKE-AUX (AUX/LAX) proteins, plays a crucial role in auxin distribution. In this study, six PIN and four AUX/LAX genes were identified in ramie (Boehmeria nivea L.). We used qRT-PCR to characterize and analyze the two gene families, including phylogenetic relationships, intron/exon structures, cis-elements, subcellular localization, and the expression patterns in different tissues. The expression of these genes in response to indole-3-acetic acid (IAA) treatment and drought stress was also assessed; the results indicate that most of the BnAUX/LAX and BnPIN genes were regulated as a result of IAA treatment and drought stress. Our study provides insights into ramie auxin transporters and lays the foundation for further analysis of their biological functions in ramie fiber development and adaptation to environmental stresses.

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 354〈/p〉 〈p〉Author(s): Vanessa Pino, Alex McBratney, Mario Fajardo, Neil Wilson, Rosalind Deaker〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The patterns of soil biodiversity across different soil gradients still require evaluation in different environments. A close relationship between soil biodiversity and soil physicochemical properties (e.g. soil pH) is evident in most studies, but a large unexplained residual variance is usually reported. This suggests that a deeper exploration into the multidimensional nature of these biotic-abiotic interactions will help develop our understanding of how a combination of soil properties drives soil biodiversity more than any one soil attribute. This was tested by analysing the multivariate associations between soil microbial diversity and soil physicochemical heterogeneity across different Australian soil landscapes. The study area involved two orthogonal transects each of ~1000 km across the state of New South Wales (NSW). A set of 33 abiotic attributes including soil properties and other key environmental covariates were correlated against a soil microbial DNA dataset (16S rRNA and ITS genes) to profile the soil bio-physicochemical relationships. This was undertaken for two land use archetypes representing natural and managed ecosystems. The study found that soil microbial communities were highly related to multiple soil attributes and vegetation. Even though the extent of these relationships varied depending on the environmental scenario and the structural microbial community component analysed, the multidimensional association with soil heterogeneity was evident beyond any single soil property, environmental gradient or land use.〈/p〉〈/div〉 〈/div〉

Description: The genetic architecture and the genetic loci controlling commodity traits in this Hami melon have not been characterized. Multiplexed shotgun genotyping (MSG) was used to genotype an F2 population of 370 Chinese Hami melon progeny. A total of 47,609 single nucleotide polymorphism (SNP) markers were obtained after strict filtering. Thebins were used to construct a genetic linkage map with a total length of 1572.954 cM. Quantitative trait locus (QTL) analysis revealed that fruit color was controlled by one major gene about 2 Mb region on chr09, while exocarp color (EC) was controlled by one major gene about 1.9 Mb on chr04, and skin spotting was controlled by two dominant genes, one in the same region of chr04as the EC QTL and the other in the 1031.05 kb region on chr02. Two major QTLs on chr03 and chr05 were related pleiotropically to several quantitative fruit traits, namely, edge sugar content (ES), center sugar content (CS), fruit weight (FW), and fruit length (FL). A further QTL on chr09 also influenced ES, while five other QTLs affected FL. This study was the first to conduct genetic architecture analysis and QTL mapping in Chinese Hami melon with high-density markers and a large target population.

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 353〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 354〈/p〉 〈p〉Author(s): Irina Kurganova, Agustin Merino, Valentin Lopes de Gerenyu, Nieves Barros, Olga Kalinina, Luise Giani, Yakov Kuzyakov〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Abandonment of croplands ongoing on 220 million ha worldwide contributes strongly to soil restoration by improvement of degraded properties and medium- and long-term carbon (C) sequestration in post-agricultural ecosystems. Two interrelated processes – decomposition and stabilization of soil organic carbon (SOC) – govern SOC dynamics and affect the C source or sink functions of former croplands. We investigated how the abandonment of arable soils affects (i) accumulation of SOC, its composition, stability, and turnover during the post-agricultural restoration of soils, and (ii) microbial activity parameters. A chronosequence study was carried in two bioclimatic zones of European Russia: deciduous forest (〈em〉Luvic Phaeozems〈/em〉, PH-chronosequence) and dry steppe (〈em〉Calcic Chernozems〈/em〉, CH-chronosequence). Each chronosequence included an arable soil, 3–4 soils abandoned at increasing time periods (up to 35 years), and natural soil: never cropped Phaeozem and completely restored Chernozem. We combined the results of nuclear magnetic resonance (NMR), thermal analysis including Differential Scanning Calorimetry and Derivative Thermogravimetry, long-term incubation for SOC mineralization, and microbiological activity (basal respiration and microbial C content). Degraded Phaeozems with low SOC amount had much higher relative increase in SOC content (134%) during the post-agricultural restoration compared to SOC-rich Chernozems (38%). SOC gains were recorded in all organic compound classes identified by NMR and thermal analysis, but the increase of recalcitrant SOC was more pronounced in the post-agricultural Chernozems than in the Phaeozems. The post-agricultural Chernozems were characterized by higher SOC aliphaticity and aromaticity than Phaeozems. Microbial activity and biodegradable SOC increased gradually during post-agricultural restoration. Being mostly a function of climate and vegetation, the soil type was the primary factor explaining the greatest portion (54–88%) of the total variance for most soil and microbial parameters. Concluding, despite SOC content increased in both Chernozems and Phaeozems during the post-agricultural restoration, the mechanisms of C sequestration and stabilization were dependent on climate, vegetation, and on the degradation intensity during the agricultural use. The accumulation of organic compounds was specific for virgin soils dominating in deciduous forest and steppes, and had direct consequences for microbial activities, C turnover and sequestration.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0016706118319086-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: Warm-season turfgrass species prevail in tropical and subtropical areas, but can also be grown in the transition zone. In this case, cold tolerance is a key aspect for germination and successful turfgrass establishment. The germination response to sub-optimal temperatures was investigated for Cynodon dactylon (cvs Jackpot, La Paloma, Transcontinental, Yukon, Riviera), Buchloe dactyloides (cv SWI 2000) and Paspalum vaginatum (cv Pure Dynasty). Four temperature regimes were applied, i.e., 20/30 °C, 15/25 °C, 10/20 °C and 5/15 °C, with a 12:12 h (light:dark) photoperiod. Germination assays were performed twice, with six replicates (Petri dishes) per treatment in each experiment, fifty seeds per dish. The final germinated percentages at last inspection time (FGP) were obtained for each Petri dish and processed by using a generalized linear mixed model (binomial error and logit link). Germination curves were fitted to each Petri dish by using time-to-event methods and germination rates (GR) for the 10th, 20th and 30th percentiles were derived and used to fit a linear thermal-time model. For all cultivars, FGP decreased with decreasing mean daily temperatures. Base temperatures (Tb) ranged between 11.4 °C and 17.0 °C, while the thermal time to obtain 30% germination ranged from 51.3 °C day for SWI 2000 to 144.0 °C day for Pure Dynasty. The estimated parameters were used to predict germination time in the field, considering the observed soil temperatures in Legnaro. The estimated date for the beginning of germination in the field would range from early April for SWI 2000 and Transcontinental to mid-May for Riviera. These results might be used as a practical support for planning spring sowing, which is crucial for successful turfgrass establishment, especially without irrigation.

Description: Terminal drought greatly enhanced Aspergillus flavus Link infection (AI) and aflatoxin contamination (AC) in peanut. Identification of new surrogate traits which have an association with AC may be effective to improve peanut varieties with reduced AI and AC. The objective of this work was to examine the relationships of nutrient uptake and N2-fixation (NF) with AC in peanut in a terminal drought condition. Five peanut varieties were tested in well-watered (WW) and terminal drought (TD) conditions (1/3 available water (AW) from R7 (7th reproductive growth stage; beginning of pod maturity stage)). Data were collected for nutrient uptake (nitrogen, phosphorus, potassium, calcium, magnesium), nodule dry weight (NDW), and NF. AI and AC were also examined. Nutrient uptake, NDW, and NF had negative and significant correlations with AI and AC in the TD condition. Negative and significant correlations of the drought tolerance index of nutrient uptake, NDW, and NF with AI and AC were also observed in the TD condition. The results showed that the ability to maintain nutrient uptake and NF in TD might be a mechanism of tolerance to AI and AC. Moreover, due to their negative impacts on AI and AC, nutrient uptake and NF could be used as selection traits for resistance to AI and AC in peanut in TD.

Description: Red rice (O. sativa) is one the most prevalent and damaging weed problems in direct seeding rice systems worldwide and can cause significant losses in rice productivity and quality. Red rice has been a problem in the United States for decades, and it is a growing problem in Asia, where 90 percent of the global rice production occurs. Unlike for other crops, where genetically engineered (GE) herbicide tolerant varieties are available, to date, Clearfield (CL) and Provisia rice are the only technologies available to selectively control red rice using chemical herbicides in commercial rice fields. We develop a counterfactual scenario without CL rice and ascertain the yield and quality losses due to red rice infestation in the Mid-South of the United States. Our findings suggest that even with the higher costs of CL rice, relative to non-CL rice, that the returns are $0.15, $0.36, and $0.54 more for every dollar invested than non-CL rice with a light, moderate, and heavy initial red rice infestation rate, respectively. These results imply that the higher upfront costs for CL rice are offset by more than proportional higher profits relative to their non-CL rice counterparts.

Description: According to the assumptions of Organisation for Economic Co-operation and Development OECD, the share of biofuels in the global transport sector is estimated to reach 15–23% by 2050. The triticale can be used to produce bioethanol. The appropriate production process should generate as much renewable energy as possible per production unit. Plant production can be carried out in various tillage systems and using appropriate doses of nitrogen fertilization. The objective of this study is to compare the effect of traditional tillage system (TRD) and reduced (RED) tillage technology and nitrogen fertilizer (0, 40, 80, 120 kg N ha−1) on grain and bioethanol yield of spring triticale. The field experiment was performed in the south east of Poland (50°42′ N, 23°15′ E) on medium dystrophic typical brown soil. Based on research and calculations, the TRD system and between 40 and 80 kg ha−1 of N fertilizer are recommended for use in the cultivation of triticale for bioethanol production purposes. Such a variant will ensure a sufficient yield of grain (5.190 and 5.803 t ha−1), starch (3.462 and 3.871 t ha−1) and bioethanol (2487.3 and 2780.7 L ha−1) and good agronomic efficiency of N fertilizer (16.96 and 12.15 L of bioethanol per 1 kg of nitrogen (N) applied). The best ratio of energy efficiency of bioethanol production (EROI—Energy Return on (Energy) Investment or “net energy”) was recorded for the TRD system (1.138:1) and for the N fertilizer at 40 kg N ha−1 (1.144:1).

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 354〈/p〉 〈p〉Author(s): Yujie Zhou, Zhenyi Jia, Junxiao Wang, Lian Chen, Mengmeng Zou, Yan Li, Shenglu Zhou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To study the heavy metal contamination and its transfer patterns in a wheat-rice rotation system in Dingshu, a typical industry county in China, 52 pairs of complete crop samples and corresponding soil samples (0–20 cm) were collected from this area. All samples were detected for the total concentrations of six heavy metals. Available factions and main soil properties were also analyzed. The results showed that Cd, Ni, Pb and Zn in both soil had moderate accumulation and these elements in corresponding grains exceeded their standard values to some extent. Most of these metals had higher concentrations in the eastern and central regions in both crop grains and the corresponding soils, which were related to the strong human activities in this region. In particular, the distribution of Cd in both soils and crops exhibited the most significant spatial correlation, whereas Cr had opposite trends. These elements in wheat and rice grains was related to different influencing factors and varied with different heavy metals. Cross-correlograms further quantitated the spatial influencing factors of elements in soils and various organs on crop gains. Cd prediction models for rice and wheat grains were stimulated based on nonedible organs and soil properties with a maximum 〈em〉r〈/em〉〈sup〉2〈/sup〉 of 0.748. These models are helpful to predict Cd accumulation in grains within wheat-rice rotation systems and thus allow farmers to reduce threats of heavy metals by adopting certain agronomic practices in different periods.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 355〈/p〉 〈p〉Author(s): Xiaolei Huang, Zhixin Jia, Junjie Guo, Tingliang Li, Dasheng Sun, Huisheng Meng, Guanghui Yu, Xinhua He, Wei Ran, Shusheng Zhang, Jianping Hong, Qirong Shen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soils play a vital role in the global carbon (C) cycle, yet little is known about the calcium (Ca)-mediated stabilization of soil organic carbon (SOC) in calcareous soils. With wet sieving, density fractionation and an incubation experiment from field soils, we investigated the effects of long-term fertilization on the Ca-mediated stabilization of aggregate-associated organic C and on the SOC stock at a soil depth of 0–20 cm in a reclaimed Cambisol on the Loess Plateau of China. Compared to the initial soil, after ten years the SOC stock increased by 50%, 76%, 94% and 110% in soils amended with no fertilizer (control), 100% chemical fertilizer, 50% chemical fertilizer plus 50% chicken manure compost and 100% chicken manure compost, respectively. The specific C mineralization rate (SCMR, rate per unit SOC) decreased as silt and clay 〉 macroaggregate 〉 microaggregate, indicating that SOC in microaggregates was more stable than in macroaggregates and the silt and clay fraction. The exchangeable Ca in the bulk soil (〈em〉P〈/em〉 〈 0.001) and soil aggregates (〈em〉P〈/em〉 〈 0.001) were positively correlated with the SOC, whereas the Ca carbonate (CaCO〈sub〉3〈/sub〉) was negatively correlated with the SCMR (〈em〉P〈/em〉 〈 0.001). The application of compost not only increased the exogenous C inputs but also promoted the transformation of CaCO〈sub〉3〈/sub〉 to exchangeable Ca compared with the sole chemical fertilization. Furthermore, organic fertilization significantly increased the organic C in the heavy fraction (〉 2.0 g cm〈sup〉−〈/sup〉〈sup〉3〈/sup〉) compared with the sole chemical fertilization, which was positively correlated with the mass proportion of macroaggregates (〈em〉P〈/em〉 〈 0.001). These results indicate that organic fertilization can enhance the availability of Ca for C binding possibly by forming organo-Ca complexes, which in turn improve soil aggregation, and thus contribute to a long-term SOC sequestration in reclaimed soils of the Loess Plateau of China.〈/p〉〈/div〉 〈/div〉

Description: Tamarix spp. are ecological threats in the Southwest U.S.A. because they displace native vegetation, increase soil salinity, and negatively affect soil microbial communities. After Tamarix L. removal, legacy effects often necessitate restoration to improve ecosystem services of Tamarix-impacted communities. Commercial mycorrhizae fungal inoculation has been recommended to improve restoration success, although inoculation treatments are rarely tested on lesser-known facultative riparian species. Our study asked two questions: (1) Can a commercial mycorrhizal fungal inoculant increase native Baccharis salicifolia (Ruiz & Pav.) Pers. (mule-fat) performance against Tamarix chinensis Lour. (i.e., tamarisk) and is this influenced by tamarisk leaf litter? (2) Is mycorrhizal colonization of mule-fat roots influenced by tamarisk stem density and leaf litter? A greenhouse experiment was performed with mule-fat cuttings in soil collected from a tamarisk monoculture. Treatments were factorial combinations of tamarisk stem densities (0, 1, 2, 3, 4 stems pot−1) with or without mycorrhizal inoculation and tamarisk litter. There were five replications and two greenhouse runs. The total biomass of both species was determined and mule-fat arbuscular mycorrhizal colonization rates were determined via the magnified intersection method. Increasing tamarisk biomass negatively affected mule-fat biomass, but there were interactions with tamarisk biomass, litter and mycorrhizal inoculation, with litter and inoculation increasing mule-fat growth at high tamarisk biomass. Arbuscular mycorrhizal colonization was high in all treatments, yet at higher tamarisk stem densities, inoculation and litter improved colonization. Interestingly, litter did not negatively impact mule-fat as predicted. Moreover, litter and mycorrhizal inoculum interacted with tamarisk to improve mule-fat growth at higher tamarisk biomass, suggesting an opportunity to improve restoration success when in competition with tamarisk.

Description: The productivity of maize in Ethiopia has remained lower than the world average because of several biotic and abiotic factors. Stemborers and poor soil fertility are among the main factors that contribute to this poor maize productivity. A novel cropping strategy, such as the use of push-pull technology, is one of the methods known to solve both challenges at once. A push-pull technology targeting the management of maize stemborers was implemented in the Hawassa district of Ethiopia with the ultimate goal of increased food security among smallholder farmers. This study evaluated farmers’ perception of push-pull technology based on their experiences and observations of the demonstration plots that were established on-farm in Dore Bafano, Jara Gelelcha and Lebu Koremo village of the Hawasa district in 2016 and 2017. This study examined farmers’ perception of the importance of push-pull technology in controlling stemborers and improving soil fertility and access to livestock feed. In both cropping seasons, except for Jara Gelelcha, the maize grain yields were significantly higher in the climate-adapted push-pull plots compared to the maize monocrop plots. The majority (89%) of push-pull technology-practising farmers rated the technology better than their maize production methods on attributes such as access to new livestock feed and the control of stemborer damage. As a result, approximately 96% of the interviewed farmers were interested in adopting the technology starting in the upcoming crop season. Awareness through training and effective dissemination strategies should be strengthened among stakeholders and policymakers for the sustainable use and scaling-up of push-pull technology.

Description: Use of saline water for irrigation is essential to mitigate increasing agricultural water demands in arid and semi-arid regions. The objective of this study is to address the potential of using straw biochar as a soil amendment to promote wheat production under saline water irrigation. A field experiment was conducted in a clay loam soil from eastern China during 2016/2017 and 2017/2018 winter wheat season. There were five treatments: freshwater irrigation (0.3 dS m−1), saline water irrigation (10 dS m−1), saline water irrigation (10 dS m−1) combined with biochar of 10, 20, 30 t ha−1. Saline water irrigation alone caused soil salinization and decreased wheat growth and yield. The incorporation of biochar decreased soil bulk density by 5.5%–11.6% and increased permeability by 35.4%–49.5%, and improved soil nutrient status. Biochar also reduced soil sodium adsorption ratio by 25.7%–32.6% under saline water irrigation. Furthermore, biochar alleviated salt stress by maintaining higher leaf relative water content and lower Na+/K+ ratio, and further enhanced photosynthesis and relieved leaf senescence during reproductive stages, leading to better grain formation. Compared to saline water irrigation alone, biochar application of 10 and 20 t ha−1 significantly increased wheat grain yield by 8.6 and 8.4%, respectively. High dose of biochar might increase soil salinity and limit N availability. In the study, biochar amendment at 10 t ha−1 would be a proper practice at least over two years to facilitate saline water irrigation for wheat production. Long-term studies are recommended to advance the understanding of the sustainable use of straw biochar.

Description: Chokeberry (Aronia melanocarpa L.) contains a large number of bioactive compounds, which make of it a highly nutritional and antioxidant food with anti-cancer and anti-inflammatory properties. It has been recently seen its consumption increased because of its interesting composition and properties as a functional food. The ultrasound-assisted extraction method has been optimized, since it is a simple and fast technique to extract phenolic compounds, as well as anthocyanins, not only separately but also simultaneously. Multiple response has been optimized and demonstrated an effectiveness level similar to the individual ones. This represents a considerable reduction in costs, time and work. The optimal conditions for simultaneous extractions were: 54% methanol as extraction solvent at pH 2.72 and 69.4 °C temperature, 70% amplitude, 0.7 s cycle, and 0.5:18.2 g:mL sample mass/solvent volume ratio. The developed methods showed a high precision level with coefficients of variation lower than 5%. The methods were successfully applied to commercial samples. Additionally, the extraction of other compounds of biological interest, such as organic acids and sugars, was also studied.

Description: In Chile, durum wheat is cultivated in high-yielding Mediterranean environments, therefore breeding programs have selected cultivars with high yield potential in addition to grain quality. The genetic progress in grain yield (GY) between 1964 and 2010 was 72.8 kg ha−1 per year. GY showed a positive and significant correlation with days to heading, kernels per unit ground area and thousand kernel weight. The gluten and protein content tended to decrease with the year of cultivar release. The correlation between the δ13C of kernels and GY was negative and significant (−0.62, p 〈 0.05, for all cultivars; and −0.97, p 〈 0.001, excluding the two oldest cultivars). The yield progress (genetic plus agronomic improvements) of a set of 40–46 advanced lines evaluated between 2006 and 2015 was 569 kg ha−1 per year. Unlike other Mediterranean agro-environments, a longer growing cycle together with taller plants seems to be related to the increase in the GY of Chilean durum wheat during recent decades.

Description: 〈p〉Publication date: 1 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 355〈/p〉 〈p〉Author(s): Steffen A. Schweizer, Franziska B. Bucka, Markus Graf-Rosenfellner, Ingrid Kögel-Knabner〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Aggregation assembles different size mixtures of soil particles into a larger architecture. Such mixtures impede resolving which particles build aggregates and how these control the accumulation of soil organic matter (OM). Here we present an approach to differentiate the size distributions of soil fractions in the size range of microaggregates (〈250 μm) from their dispersible particle-size distribution using dynamic image analysis. This approach enabled us to differentiate the magnitude and preferential size ranges of aggregates and non-aggregated particles. Wet sieving was used to isolate free microaggregate-sized fractions. Larger soil structures 〉250 μm were sonicated to isolate occluded size fractions 〈250 μm. To investigate the impact of soil texture, we analyzed topsoil samples of an arable site on Cambisol soils with a gradient in clay content of 16–37% and organic carbon concentrations of 10–15 g kg〈sup〉−1〈/sup〉. Our results demonstrate how soil texture governs aggregate size distributions: most water-stable microaggregates were found to be of approximately 30 μm diameter, independent of the clay content gradient. High-clay soils contain more water-stable macroaggregates (〉250 μm) and larger microaggregates in the 50–180 μm size range. The low-clay soils, on the other hand, contained more non-aggregated sand-sized particles 〉100 μm which probably hampered the buildup of larger aggregates. The size distribution of particles 〈100 μm in size fractions 〈250 μm showed a similar prevailing soil texture pattern, with approximately 24% clay, 59% silt, and 17% sand-sized particles at all clay contents. In contrast to the prevailing texture pattern along the clay content gradient, 4% more clay-sized particles helped build up water-stable macroaggregates. In the low-clay soils, the aggregates were smaller and the size fractions 〈53 μm had higher OM concentrations. This indicates that the low-clay soils held most of their OM in smaller microaggregates. Such arrangement of OM in smaller microaggregates demonstrates that soil texture may control OM stabilization mostly indirectly via the distribution of OM in different aggregate fractions. The occlusion of microaggregates in larger structures led to lower alkyl:O/N-alkyl ratios in 〈sup〉13〈/sup〉C nuclear magnetic resonance (NMR) spectroscopy, indicating increased preservation.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 355〈/p〉 〈p〉Author(s): Pengpeng Duan, Yanfeng Song, Shuangshuang Li, Zhengqin Xiong〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Greenhouse vegetable field is one of the main sources of agricultural nitrous oxide (N〈sub〉2〈/sub〉O) emissions via multiple pathways regulated by different microbes. However, the relative contributions of nitrifier nitrification, nitrifier denitrification, nitrification-coupled denitrification and heterotrophic denitrification to N〈sub〉2〈/sub〉O production with temperature change in different greenhouse vegetable soils are poorly understood. In this study, combined approaches of the 〈sup〉15〈/sup〉N–〈sup〉18〈/sup〉O labeling technique and transcriptome analyses were applied to investigate the pathways of N〈sub〉2〈/sub〉O production (nitrifier nitrification, nitrifier denitrification, nitrification-coupled denitrification and heterotrophic denitrification) under 15, 25 and 35 °C in six greenhouse vegetable field soils in mainland China. The results show that heterotrophic denitrification was an important source of N〈sub〉2〈/sub〉O in acidic greenhouse vegetable soils, whereas nitrifier nitrification was the dominant source of N〈sub〉2〈/sub〉O in alkaline greenhouse vegetable soils. In addition, the contribution of nitrifier denitrification and nitrification-coupled denitrification to N〈sub〉2〈/sub〉O production in alkaline greenhouse vegetable soils were higher than in acidic greenhouse vegetable soils. The contribution of nitrification-coupled denitrification increased with temperature at 15–35 °C, whereas nitrifier denitrification increased with temperature at 15–25 °C. Overall, high temperature decreased the contribution of nitrifier nitrification to N〈sub〉2〈/sub〉O production. These results have important implications for understanding the temperature-dependent N〈sub〉2〈/sub〉O production pathways and for mitigating agricultural N〈sub〉2〈/sub〉O emissions under different soil and temperature conditions.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0016706119305762-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: Optimal manure management can maximize agronomic benefits and minimize environmental impacts. Field experiments were conducted in the Pacific Northwest (Vancouver, Canada) to determine how chicken and horse manures that were fall-applied to meet nitrogen crop demand affect soil ammonium (NH4+) and nitrate (NO3−), apparent net mineralization (ANM) and nitrification (ANN), crop biomass and nutrient concentration, and fluxes of nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4). Relative to horse manure, chicken manure increased soil NH4+ by 60-fold, ANM by 2-fold, and ANN by 4-fold. Emissions of N2O (+600%) and CO2 (+45%) were greater and growing season CO2 emissions (−40%) were lower after application of chicken than horse manure. Productivity of cover crop (+30%), legume cover crop (−25%), and squash cash crop (+20%) were affected by chicken relative to horse manure. Overall, fall-applied chicken manure increased yields, N availability, and environmental impacts relative to horse manure.

Description: The burdens of malnutrition, protein and micronutrient deficiency, and obesity cause enormous costs to society. Crop nutritional quality has been compromised by the emphasis on edible yield and through the loss of biodiversity due to the introduction of high-yielding, uniform cultivars. Heirloom crop cultivars are traditional cultivars that have been grown for a long time (〉50 years), and that have a heritage that has been preserved by regional, ethnic, or family groups. Heirlooms are recognized for their unique appearance, names, uses, and historical significance. They are gaining in popularity because of their unique flavors and cultural significance to local cuisine, and their role in sustainable food production for small-scale farmers. As a contrast to modern cultivars, heirlooms may offer a welcome alternative in certain markets. Recently, market channels have emerged for heirloom cultivars in the form of farmer–breeder–chef collaborations and seed-saver organizations. There is therefore an urgent need to know more about the traits available in heirloom cultivars, particularly for productivity, stress tolerance, proximate composition, sensory quality, and flavor. This information is scattered, and the intention of this review is to document some of the unique characteristics of heirloom cultivars that may be channeled into breeding programs for developing locally adapted, high-value cultivars.

Description: Acid soils and associated Al3+ toxicity are prevalent in Ethiopia where normally Al3+-sensitive durum wheat (Triticum turgidum ssp durum Desf.) is an important crop. To identify a source of Al3+ tolerance, we screened diverse Ethiopian durum germplasm. As a center of diversity for durum wheat coupled with the strong selection pressure imposed by extensive acid soils, it was conceivable that Al3+ tolerance had evolved in Ethiopian germplasm. We used a rapid method on seedlings to rate Al3+ tolerance according to the length of seminal roots. From 595 accessions screened using the rapid method, we identified 21 tolerant, 180 intermediate, and 394 sensitive accessions. When assessed in the field the accessions had tolerance rankings consistent with the rapid screen. However, a molecular marker specific for the D-genome showed that all accessions rated as Al3+-tolerant or of intermediate tolerance were hexaploid wheat (Triticum aestivum L.) that had contaminated the durum grain stocks. The absence of Al3+ tolerance in durum has implications for how Al3+ tolerance evolved in bread wheat. There remains a need for a source of Al3+-tolerance genes for durum wheat and previous work that introgressed genes from bread wheat into durum wheat is discussed as a potential source for enhancing the Al3+ tolerance of durum germplasm.

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 354〈/p〉 〈p〉Author(s): Fabian E. Gruber, Jasmin Baruck, Volkmar Mair, Clemens Geitner〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Parent material is an important factor of soil formation and consequently plays a dominant role in both traditional field soil survey and digital soil mapping. The emergence of a new generation of detailed geological maps at high spatial resolution in South Tyrol raises the question of how to effectively incorporate these into soil mapping efforts. By comparing the units of these geological maps with the parent material description of soil pits, we evaluate to what extent these can be used as soil parent material maps. Random forest classification and feature selection are applied to highlight those terrain parameters that i) best distinguish between the different surficial geology units, ii) separate soil profile sites with different soil parent material, and iii) can be used together with the geologic map to train a classifier to model the distribution of soil parent material in the study area. The main issue detected by analyzing the differences between the geologic map units and the soil parent material information is the dominant role of till, which acts as soil parent material for a large number of soils located on different geological map units. While slope debris is another class on which geological map and soil pit descriptions often disagree, the issues concerning its misclassification are connected more to categorical transitions between soil parent material classes. Terrain parameters characterizing surface roughness, specifically a combination of vector ruggedness measure (VRM) and topographic roughness index (TRI), were identified as being best suited to join the geological map units in modeling soil parent material and indicate areas where till as soil parent material should be expected. By evaluating these results together with the distribution of soil types, a geologic-topographic characterization is performed for each geological map unit, with the aim of highlighting specific combinations of geological units and topographical situations which should be in the center of future detailed soil surveys, consequently facilitating the soil mapping procedure.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 354〈/p〉 〈p〉Author(s): I. Kouchami-Sardoo, H. Shirani, I. Esfandiarpour-Boroujeni, J. Álvaro-Fuentes, H. Shekofteh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Threshold friction velocity (u〈sub〉⁎t〈/sub〉) is a very important parameter, which represents wind erosion potential. Because of the difficulty of measuring u〈sub〉⁎t〈/sub〉, it would be advantageous if u〈sub〉⁎t〈/sub〉 could be estimated indirectly from its effecting factors that can be easily measured. The main purpose of this research was to quantify relationships between u〈sub〉⁎t〈/sub〉 and various topsoil features using inexpensive approaches. To prepare a reliable dataset, we used a portable wind tunnel for measuring u〈sub〉⁎t〈/sub〉 at a total of 118 observation points in Kerman province, southeast Iran. We developed a non-dominated sorting genetic algorithm II (NSGA-II), specifically designed to operate with artificial neural network (ANN) to select the most determinant properties that influence u〈sub〉⁎t〈/sub〉. A permutation of nine input features including surface crust (SC), gravel coverage (GC), very fine sand (VFS), fine sand (FS), very coarse sand (VCS), electrical conductivity (EC), sodium adsorption ratio (SAR), calcium carbonate equivalent (CCE), and mean weight diameter (MWD), was introduced as explanatory variables. We also examined the potential power of using a Multi-Layer Perception (MLP) neural network for prediction of u〈sub〉⁎t〈/sub〉 changes in response to spatial variation of the selected features. The results of constructed MLP model revealed the ability of the model for u〈sub〉⁎t〈/sub〉 prediction and showed that the coefficient of determination (R〈sup〉2〈/sup〉) values were 0.91 and 0.89 for training and testing data, respectively. Furthermore, acceptable level of the statistical validation criteria verified reliable performance of the MLP model. This research provided a powerful basis for prediction of u〈sub〉⁎t〈/sub〉 from topsoil features and surface roughness in arid and semi-arid areas of Iran; however, its generic framework could be used to other arid and semi-arid regions with similar challenges.〈/p〉〈/div〉 〈/div〉

Description: The availability of big data in agriculture, enhanced by free remote sensing data and on-board sensor-based data, provides an opportunity to understand within-field and year-to-year variability and promote precision farming practices for site-specific management. This paper explores the performance in durum wheat yield estimation using different technologies and data processing methods. A state-of-the-art data cleaning technique has been applied to data from a yield monitoring system, giving a good agreement between yield monitoring data and hand sampled data. The potential use of Sentinel-2 and Landsat-8 images in precision agriculture for within-field production variability is then assessed, and the optimal time for remote sensing to relate to durum wheat yield is also explored. Comparison of the Normalized Difference Vegetation Index(NDVI) with yield monitoring data reveals significant and highly positive linear relationships (r ranging from 0.54 to 0.74) explaining most within-field variability for all the images acquired between March and April. Remote sensing data analyzed with these methods could be used to assess durum wheat yield and above all to depict spatial variability in order to adopt site-specific management and improve productivity, save time and provide a potential alternative to traditional farming practices.

Description: Kura clover living mulch (KCLM) systems have been previously investigated for their incorporation into upper Midwestern row crop rotations to provide ecosystem services through continuous living cover. Reductions in soil erosion and nitrate loss to surface and groundwater have been reported, but factors affecting agronomic performance and nutrient management are not well defined. To achieve realized environmental benefits, research must develop agronomic management techniques, determine economic opportunities, and provide management recommendations for row crop production in KCLM systems. Two experiments were conducted in 2017 and 2018 to determine the response to N fertilizer application for maize production in KCLM. The first-year maize experiment followed forage management, and the second-year maize experiment followed maize after forage management. Eight fertilizer N treatments ranging from 0–250 kg N ha−1 were applied to each experiment and grain and stover yields were compared to conventionally managed maize hybrid trials that were conducted nearby. First-year maize did not need fertilizer N to maximize yield and profitability in either growing season, and second-year maize required a fertilizer N rate near local University guidelines for maize following soybean. The net economic return from maize grain and stover in the KCLM averaged over first and second-year maize experiments and 2017 and 2018 growing seasons were $138 ha−1 greater than the conventional comparison.

Description: The agricultural area in the Po Valley is prone to high nitrous oxide (N2O) emissions as it is characterized by irrigated maize-based cropping systems, high amounts of nitrogen supplied, and elevated air temperature in summer. Here, two monitoring campaigns were carried out in maize fertilized with raw digestate in a randomized block design in 2016 and 2017 to test the effectiveness of the 3, 4 DMPP inhibitor Vizura® on reducing N2O-N emissions. Digestate was injected into 0.15 m soil depth at side-dressing (2016) and before sowing (2017). Non-steady state chambers were used to collect N2O-N air samples under zero N fertilization (N0), digestate (D), and digestate + Vizura® (V). Overall, emissions were significantly higher in the D treatment than in the V treatment in both 2016 and 2017. The emission factor (EF, %) of V was two and four times lower than the EF in D in 2016 and 2017, respectively. Peaks of NO3-N generally resulted in N2O-N emissions peaks, especially during rainfall or irrigation events. The water-filled pore space (WFPS, %) did not differ between treatments and was generally below 60%, suggesting that N2O-N emissions were mainly due to nitrification rather than denitrification.

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 354〈/p〉 〈p〉Author(s): José A.M. Demattê, André Carnieletto Dotto, Ariane F.S. Paiva, Marcus V. Sato, Ricardo S.D. Dalmolin, Maria do Socorro B. de Araújo, Elisângela B. da Silva, Marcos R. Nanni, Alexandre ten Caten, Norberto C. Noronha, Marilusa P.C. Lacerda, José Coelho de Araújo Filho, Rodnei Rizzo, Henrique Bellinaso, Márcio R. Francelino, Carlos E.G.R. Schaefer, Luiz E. Vicente, Uemeson J. dos Santos, Everardo V. de Sá Barretto Sampaio, Rômulo S.C. Menezes〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present study was developed in a joint partnership with the Brazilian pedometrics community to standardize and evaluate spectra within the 350–2500 nm range of Brazilian soils. The Brazilian Soil Spectral Library (BSSL) began in 1995, creating a protocol to gather soil samples from different locations in Brazil. The BSSL reached 39,284 soil samples from 65 contributors representing 41 institutions from all 26 states. Through the BSSL spectra database, it was possible to estimate important soil attributes, such as clay, sand, soil organic carbon, cation exchange capacity, pH and base saturation, resulting in differences among the multi-scale models taking Brazil (overall), regional and state scale. In general, spectral descriptive and quantitative behavior indicated important relationship with physical, chemical and mineralogical properties. Statistical analyses showed that six basic patterns of spectral signatures represent the Brazilian soils types and that environmental conditions explain the differences in spectra. This study demonstrates that spectroscopy analyses along with the establishment of soil spectral libraries are a powerful technique for providing information on a national and regional levels. We also developed an interactive online platform showing soil sample locations and their contributors. As soil spectroscopy is considered a fast, simple, accurate and nondestructive analytical procedure, its application may be integrated with wet analysis as an alternative to support the sustainable management of soils.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0016706118318548-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 354〈/p〉 〈p〉Author(s): Fujun Niu, Zeyong Gao, Zhanju Lin, Jing Luo, Xingwen Fan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil hydrological processes are extremely complex in high-altitude regions and are recognized to have positive effects on soil quality, nutrient cycling, herbage yield, and runoff generation. However, soil hydrological processes have not been fully quantified in permafrost regions of the Qinghai-Tibet Plateau (QTP). To fill this gap, the soil water dynamics, soil water storage, soil infiltration processes, soil water retention and soil hydraulic conductivity were systematically monitored in different alpine ecosystems (alpine wet meadow (AWM), alpine meadow (AM), and alpine steppe (AS)). The results revealed that the soil water content was significantly higher in AWM soil in the shallow layer, while it was higher in AM soil in the deeper layer. Moreover, the response of soil water to rainfall was markedly more sensitive in AS soil than in AM and AWM soils. The average soil water storage amount reached 440 mm in the 0–100 cm soil interval of the AM, which was nearly 1.6-fold higher than that in the AS and 1.2-fold higher than that in the AWM. The existence of vegetation enhanced the soil infiltration rates in AWM and AM soils 1.3-fold and 1.5-fold, respectively, and decreased the soil infiltration rate 1.2-fold in AS soil. Nuclear magnetic resonance (NMR) results indicated that soil water in AS soil was mainly composed of capillary water and mobile water but was composed of bound water and capillary water in AWM soil and AM soil, respectively. The results from a redundancy analysis (RDA) demonstrated that the vegetation in the study region regulates the soil hydrological regime by altering the soil structure and soil biochemistry. Moreover, the mechanism of vegetation influence on soil hydrological processes suggests that the regional runoff generation will shift with the vegetation succession. The information obtained in this study may aid in the understanding of changes in the ecological environment and regional hydrological cycles under climate change.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 354〈/p〉 〈p〉Author(s): M. Díaz-López, C. García, I. Garrido, S. Navarro, N. Vela, E. Nicolás, J. Fenoll, F. Bastida〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Pesticides are chemical compounds, mostly synthetic, which are used widely in agricultural fields to prevent and to control pests and soil-borne diseases. The synthetic nature of these compounds makes some of them non-biodegradable and they may accumulate in harmful concentrations in soils. Solarization seems to be a non-chemical strategy that could enhance pesticide degradation in soils. Here, we evaluate the combined impact of pesticides and solarization on the microbial community of a Mediterranean soil. For this purpose, enzyme activities, basal respiration, and the biomass and composition of the microbial community (through analysis of phospholipid fatty acids, PLFAs) were evaluated in solarized and non-solarized soils, in a 90-day greenhouse experiment with a combination of different pesticides. The degradation of the pesticides in the solarized soils was 30% greater than in non-solarized samples. However, solarization also affected the soil microbial community. The soil respiration was lowest in solarized samples without pesticides, while the enzyme activities were greater in non-solarized samples (with and without pesticides). Both the bacterial and fungal PLFA contents declined in solarized samples. The G+/G− ratio was highest in the solarized samples without pesticides and in the non-solarized samples with pesticides. Considering such impacts on the soil microbial community and the relationship of soil microbes with soil ecosystem services, the utilization of solarization must be carefully considered when adopting strategies for pesticide degradation in Mediterranean soils.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 354〈/p〉 〈p〉Author(s): Imane Haidara, Meryem Tahri, Mohamed Maanan, Mustapha Hakdaoui〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Erosion of soil and land degradation is a worldwide phenomenon caused by natural occurrence and which is accelerated by climate change. This study evaluated soil erosion vulnerability using the Fuzzy Analytical Hierarchy Process (FAHP) multi-criteria method and Geographical Information System (GIS). Six criteria were used to create the soil erosion cartography: rainfall, land cover, soil classification, slope gradient, drainage density, and land use. This method calculated the corresponding criteria weights on the feedback of several studies, and research, which may be used to determine the effectiveness in controlling soil erosion around the world. Our results highlighted the variability of erosion and clearly identified the areas at risk. Five degrees of erosion were noted: very slight erosion and slight erosion located in the south of the study site, moderate erosion present throughout the catchment area, high as well as very high erosion situated in the north of the catchment area.〈/p〉〈/div〉 〈/div〉

Description: Although compost and biochar received high attention as growing media, little information is available on the potential of vineyard by-products for the production and use of composted solid digestate (CSD) and biochar (BC). In the present study, two experiments are reported on CSD and BC mixed with commercial peat (CP) for grapevine planting material production. Four doses (0, 10%, 20%, 40% vol.) of CSD and BC were assessed in the first and second experiment, respectively. CSD mixed at a dose of 10% recorded the highest values of shoot dry weight (SDW) and a fraction of total dry biomass allocated to shoot (FTS), both cropping bench-graft and bare-rooted vine. On the other hand, CSD mixed at a dose of 40% displayed the highest values of SDW and FTS, cropping two-year-old vine. BC used at a dose of 10% improved SDW, root dry weight, total dry weight, FTS, shoot diameter, and height on bare-rooted vine. The present study shows that CSD and BC, coming from the valorization of vineyard by-products, can be used in the production of innovative growing media suitable for nursery grapevine production. Further studies are needed to assess the combined applications of CSD and BC in the same growing media.

Description: The application of nitrification inhibitors (NIs) shows promise in prolonging the ammonium presence in soil with beneficial effects for agriculture ecosystems and climate change mitigation. Although the inhibitory effect (IE) of NIs has been studied in the presence of various environmental and edaphic conditions, little is known about the effect of soil nitrification potential (NP) on the effectiveness of NIs. Here, laboratory-scale experiments were conducted to investigate the effect of the variation in soil NP rates, among land-use type and temperature, on the performance of two nitrification inhibitors, dicyandiamide (DCD) and 3,4-dimethypyrazole phosphate (DMPP), at four NI application rates imposed upon eight cropland and non-cropland soils. We found that the IE of DCD and DMPP were organized according to soil NP rates. Nevertheless, NP was lower in non-cropped soil than in cropped systems, and DMPP-based inhibition was higher than DCD. The IE of both NIs decreased with NP and the amount of NI required to achieve an IE ≈ 50%, was significantly reduced for soils that exhibited the lowest NP rates, especially for DMPP. However, the temperature did not appear to have a major influence on IE of both DCD and DMPP, demonstrating the potential of NIs to inhibit nitrification for a wider temperature range, dependent on the NI application rate. Our findings provide evidence that change in soil NP rate has important influences on the efficacy of NI which required great consideration for N-fertilizer optimization with the application of nitrification inhibitors.

Description: This study investigated the influence of biological control agents and plant growth promoters on the chemical composition of the cultivars Panda and Kora buckwheat sprouts. Before sowing, seeds were soaked in solutions containing Bacillus subtilis bacteria, Pythium oligandrum oospores, Ecklonia maxima algae extract, and/or nitrophenols. The sprouts of the Panda displayed higher levels of protein, fat, and dietary fiber fractions than the Kora. Measurable effects of biological control agents (BCAs) and plant growth promoters (PGPs) on the chemical composition of sprouts were also confirmed. Soaking the seeds in a solution containing P. oligandrum oospores resulted in a decrease in the level of crude ash in sprouts, while the addition of nitrophenols increased the level of both crude ash and protein. We also found statistically significant effects of interactions between the cultivar and BCA and/or PGP for each of the examined components.

Description: During biogas production anaerobic digestion of plant material produces a nutrient-rich residue called digestate. The application of the nutrients present in the digestate should improve soil fertility, particularly in nutrient poor soils, and thus crop yield, promoting the closure of the nutrient cycle. This study evaluated the effect of digestate application on the germination and early stages of plant development since these are the first steps to be considered when studying the benefits on plant growth in low fertility substrates. A greenhouse experiment was conducted to evaluate the effects of three substrates of different texture and fertility (field loam, field sand, sand), as well as type and amount of fertilizer (pure maize digestate vs. inorganic nitrogen/phosphorus/potassium (NPK) fertilizer) on both germination and early plant performance of maize (Zea mays L. subsp. mays). While digestate and NPK fertilizer applications had no significant effect on germination in the two field soils, digestate applications significantly decreased the germination rate in sand (36–82% reduction) due to an increase of surface water repellency. In contrast, for aboveground biomass yield, the most positive fertilization effects of digestate application were found on sand (up to 3.5 times the biomass of the unamended control) followed by field sand (1.5 times), compared to no effect for field loam. Our findings suggest that digestate application have positive fertilization effects in low-fertility substrates, similar to NPK, even though digestate application may have a negative impact on the permeability in sandy substrates that could interfere with germination.

Description: Citrus bacterial canker (CBC), caused by the plant pathogenic bacterium Xanthomonas citri subsp. citri (Xcc), is a devastating disease in many commercial citrus cultivars. Every year, CBC causes a substantial reduction in fruit quality and quantity that corresponds to significant economic losses worldwide. Endophytic microorganisms produce numerous bioactive secondary metabolites that can control plant pathogens. We investigated the antagonistic activities of 66 endophytic bacteria isolated from nine citrus cultivars to control streptomycin-resistant Xcc. The suspension of Endophytic Bacteria-39 (EB-39), identified as Bacillus velezensis, exhibited the highest antibacterial activity against three wild-type and six streptomycin-resistant Xcc strains, with the inhibition zones between 39.47 ± 1.6 and 45.31 ± 1.6 mm. The ethyl acetate extract of EB-39 also controlled both wild-type and streptomycin-resistant Xcc strains, with the inhibition zones between 29.28 ± 0.6 and 33.88 ± 1.3 mm. Scanning electron microscopy indicated the ethyl acetate extract of EB-39-induced membrane damage and lysis. The experiments using the detached leaves of a susceptible Citrus species showed that EB-39 significantly reduced the incidence of canker on the infected leaves by 38%. These results strongly suggest that our newly isolated EB-39 is a novel biocontrol agent against CBC caused by wild-type and streptomycin-resistant Xcc strains.

Description: Although arbuscular mycorrhizal (AM) fungi are known to promote growth and yield of agricultural crops, inoculation methods for effective scaling up from greenhouse to the field are still underexplored. The application of single or mixed beneficial AM fungal isolates is hindered by the lack of experimental reproducibility of findings at different scales and the cost-effectivity of inoculation methods. Seed coating has been considered a feasible delivery system of AM fungal inocula for agricultural crops. In this study, the impact of single and multiple AM fungal isolates applied via seed coating on chickpea productivity was evaluated under greenhouse and field conditions. Overall, plants inoculated with multiple AM fungal isolates had better performance than those inoculated with single AM isolate under greenhouse and field conditions. While plants in greenhouse displayed higher shoot dry weight (14%) and seed individual weight (21%), in field, inoculation with multiple AM isolates increased pod (160%), and seed (148%) numbers, and grain yield (140%). Under field conditions, mycorrhizal root colonization was significantly higher in chickpea plants inoculated with multiple AM fungal isolates compared to other treatments. These findings highlight the potential of field-inoculation with multiple AM fungal isolates via seed coating as a sustainable agricultural practice for chickpea production.

Description: The rice production system in Japan is changing due to the aging of rice farmers, shortage of labor, mechanization, and increase of large-scale rice fields and increased application of direct sowing, all of which contribute to the lack of sophisticated weed management practices. Because the changing production system has not improved and likely worsened weed management practices, weedy rice (Oryza sativa L.) has become a serious threat to rice production in Japan. We analyzed weedy rice accessions from Nagano, the central part of Japan, and other rice accessions to elucidate the origin of this weedy rice using a whole-genome single nucleotide polymorphism (SNP) array. For developing sustainable weedy rice management practices, the elucidation of the origin of re-emerging weedy rice is crucial. Population genetic analysis indicated that weedy rice in Nagano was phylogenetically independent from the local red rice cultivar with low genetic diversity. Past and recently re-emerging weedy rice ecotypes in Nagano shared a similar genetic background which implies the evolution of weedy rice by severe natural selection. Window-based FST and selection sweep analysis revealed the divergence of some of the known key domestication-related genes, such as shattering gene sh4 and qsh1, of weedy rice from domesticated rice cultivars.

Description: Crop residues are an important source of plant nutrients. However, information on the various methods of residue management on micronutrients in soil and wheat (Triticum aestivum L.) over time is limited. A long-term (84-year) agroecosystem experiment was assessed to determine the impact of fertilizer type and methods of crop residue management on micronutrients over time under dryland winter wheat-fallow rotation. The treatments were: no N application with residue burning in fall (FB), spring (SB), and no residue burn (NB); 45 kg N ha−1 with SB and NB; 90 kg N ha−1 with SB and NB; pea vines; and farmyard manure (FYM) and a nearby undisturbed grass pasture (GP). Wheat grain, straw, and soil samples from 1995, 2005, and 2015 were used to determine tissue total and soil Mehlich III extractable Mn, Cu, B, Fe, and Zn, and soil pH. After 84 years, extractable Mn and B in the top 10 cm of soil decreased in all plots, except for B in FYM and SB. The FYM plots had the highest extractable Mn (114 mg kg−1) in the top 10 cm soil; however, it declined by 33% compared to the GP (171 mg kg−1). Extractable Zn in the top 10 cm of soil increased with FYM while it decreased with inorganic N application in 2015; however, total Zn in grain increased by 7% with inorganic N (90 kg ha−1) application compared to FYM application. The results suggest that residue management had similar impact on soil micronutrients. Inorganic N and FYM application can be integrated to reduce micronutrient losses from cultivation.

Description: The tropical multiuse tree Jatropha curcas L. (jatropha) is highly promoted as oilseed crop for biodiesel production and for climate change mitigation, but cultivation practices require further research. The objectives of this study were to assess the effects of varying plant spacings (2.0 m × 4 m compared to 1.5 m × 4 m), crop establishment methods (raising plantlets in a nursery prior to planting to the field compared to direct sowing) and genotypes on seed yield, seed quality and plant height, recorded at a dry-subhumid location in Madagascar (Ihosy) and at a humid location in Cameroon (Batchenga). Averaged across treatment variants and genotypes, seed yield and seed oil content were higher at the dry-subhumid site and in particular the narrower spacing reached higher seed yields per unit area than the wider spacing. At the humid site, plant growth was characterized by strong accumulation of biomass. The establishment method tested at the dry-subhumid site showed no significant differences in the recorded parameters. Our results encourage to re-think common practices in jatropha cultivation and underpin the importance of the correct choice of location, genotype and agronomic practices considering the interactions between all factors.

Description: 〈p〉Publication date: 1 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 355〈/p〉 〈p〉Author(s): Xuebin Xu, Changwen Du, Fei Ma, Yazhen Shen, Ke Wu, Dong Liang, Jianmin Zhou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Spectroscopy is a useful method for soil monitoring because of its environmental friendliness, and its ability to produce rapid, nondestructive, simultaneous multi-element analysis. In this work, data fusion strategies for laser-induced breakdown spectroscopy (LIBS) and attenuated total reflectance Fourier-transform mid-infrared spectroscopy (FTIR-ATR), as well as a combination of multivariate calibration methods were investigated for prediction of soil organic matter (SOM) content. The root mean square error (RMSE) and residual prediction deviation (RPD) of the calibration and validation sets, systematic error, and residual assessment, were applied to evaluate the robustness and accuracy of these predictions. The results of a principal component analysis (PCA) indicated that baseline wander present in the spectral data could be effectively removed using morphological weighted penalized least squares (MPLS) and wavelet transform (WT) algorithms. The quantitative prediction ability of SOM content by a partial least squares regression (PLSR) model could be improved using principal component weighted mean (PCWM) and Euclidean distance weighted mean (EDWM) algorithms applied to parallel LIBS spectra. The prediction ability of SOM content was dramatically improved using mid-level data fusion based on the concatenation of latent variables of LIBS and FTIR-ATR spectra obtained by partial least squares algorithm. The considerable prediction accuracy and robustness were achieved using the PLSR model (R〈sub〉V〈/sub〉〈sup〉2〈/sup〉 = 0.792, RMSE〈sub〉V〈/sub〉 = 1.76 g kg〈sup〉−〈/sup〉〈sup〉1〈/sup〉, and RPD〈sub〉V〈/sub〉 = 2.16), the support vector regression (SVR) model (R〈sub〉V〈/sub〉〈sup〉2〈/sup〉 = 0.811, RMSE〈sub〉V〈/sub〉 = 1.68 g kg〈sup〉−〈/sup〉〈sup〉1〈/sup〉, and RPD〈sub〉V〈/sub〉 = 2.27), and the artificial neural network (ANN) model (R〈sub〉V〈/sub〉〈sup〉2〈/sup〉 = 0.830, RMSE〈sub〉V〈/sub〉 = 1.60 g kg〈sup〉−〈/sup〉〈sup〉1〈/sup〉, and RPD〈sub〉V〈/sub〉 = 2.39). The findings from this work suggest that the use of LIBS and FTIR-ATR spectra in combination with multivariate calibration can be a simple, fast, and nondestructive approach to monitor SOM. This strategy is potentially of great significance in the evaluation of soil fertility, the management of soil nutrients, and in guiding the agricultural production of precision agriculture.〈/p〉〈/div〉 〈/div〉

Description: In New Zealand, pastoral farming for dairy and meat production is the major land use. As with any agricultural production system, weeds are a threat to efficient pasture production in New Zealand. In this review, we outline the problems caused by weeds in New Zealand pastures, and the management strategies being used to control them. There are currently 245 plant species from 40 plant families that are considered to be troublesome weeds in New Zealand pastures. The application of herbicides is an important approach to manage weeds in New Zealand pastures; however, a key to the success of these pastures is the use of clovers in combination with the grasses, so the challenge is to find herbicides that selectively control weeds without damaging these legumes. The use of spot spraying and weed wiping are often required to ensure selective control of some weed species in these pastures. Non-chemical agronomic approaches such as grazing management and using competitive pasture species often play a more important role than herbicides for weed management in many New Zealand pastures. Thus, integrated weed management using a combination of herbicides and good pasture management strategies leads to the most cost-effective and efficient control of pasture weeds in New Zealand.

Description: The main aim of this study is to identify and investigate specific humates (Hs) as potential biostimulants. Five specialty lignosulfonates (LS1-5), one commercial leonardite-humate (PH), and one commercial lignosulfonate (LH), were analyzed for their carbon, nitrogen, and sulfur contents, and the distribution of functional groups using Fourier transform infrared (FTIR) and Raman spectroscopies. Hs were further supplied for two days to Zea mays L. in hydroponics to test their capacity to trigger changes in physiological target-responses. LS1, LS2, LS3, and LS5 determined the most pronounced effects on plant growth and accumulation of proteins and phenolics, perhaps because of their chemical and spectroscopic features. Root growth was more increased (+51–140%) than leaf growth (+5–35%). This effect was ascribed to higher stimulation of N metabolism in roots according to the increased activity of N-assimilation enzymes (GS and GOGAT) and high consumption of sugars for energy-dependent processes. Increased values of RuBisCO, SPAD (Soil Plant Analysis Development values), and leaf sugar accumulation refer to enhanced photosynthesis attributed to Hs. We conclude that Hs tested in this study functioned as biostimulants, but the specialty lignosulfonates were more efficient in this role, possibly because of the type of starting material and process used for their production, which may have influenced their chemical properties.

Description: 〈p〉Publication date: 1 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 355〈/p〉 〈p〉Author(s): Moritz Laub, Sergey Blagodatsky, Yvonne Funkuin Nkwain, Georg Cadisch〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Peak area (PA) integration of diffuse reflectance mid infrared Fourier transform spectroscopy (DRIFTS) spectra is useful to study soil organic matter (SOM) quality and as a potential modelling proxy. Residual water of soil samples after drying affects DRIFTS spectra, mainly in the region 〉2500 cm〈sup〉−〈/sup〉〈sup〉1〈/sup〉. Therefore, SOM quality related PA at different wavenumbers should be influenced to varying degrees. We studied how absolute, normalized and relative PA related to SOM functional groups (at 2930, 1620, 1530 and 1159 cm〈sup〉−〈/sup〉〈sup〉1〈/sup〉), as well as their ratios were influenced by oven drying of soil samples at increasing temperatures (from 32 °C to 105 °C). All organic and even mineral associated PA significantly increased with drying temperature. The PA of aliphatic C〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉H stretching (2930 cm〈sup〉−〈/sup〉〈sup〉1〈/sup〉), located on the shoulder of the broad O〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉H stretching PA, was influenced most strongly. Our results indicate that using 105 °C as drying temperature and storing samples in a desiccator is the best way to minimize water interference. These findings apply to relative PA and ratios of organic compounds, while no effect of drying temperatures on PA correlations to C or N were found.〈/p〉〈/div〉 〈/div〉

Description: Dutch bucket hydroponic trials were conducted with the aim to evaluate the effects of different hydroponic fertilizers (5N-4.8P-21.6K, 5N-5.2P-21.6K, and 7N-3.9P-4.1K) on growth, fruit production, and the fruit quality (fruit shape index) parameters of two cultivars of sweet pepper (Capsicum annuum L.) and on two cultivars of eggplant (Solanum melongena L.). For sweet pepper yield, the 5N-4.8P-21.6K fertilizer was responsible for the greatest yield for both cultivars. For sweet pepper fresh and dry shoot weight interaction, the ‘Orangella’ cultivar had greater growth in 5N-4.8P-21.6K and 5N-5.2P-21.6K fertilizers, whereas there was no difference among cultivars in 7N-3.9P-4.1K. Shape index was not affected by fertilizers or cultivars. For the eggplant yield, there was no main effect nor interaction between fertilizers and cultivars for fruit yield, while the interaction between fertilizers and cultivars was significant for shoot fresh weight production. Shoot fresh weight was greater for ‘Angela’ than ‘Jaylo’ in 5N-4.8P-21.6K and 7N-3.9P-4.1K. Furthermore, both eggplant cultivars were affected with yellowing of fruits in all fertilizer treatments after 2 months, which was probably due to the accumulation of nutrients in the closed hydroponic system. Therefore, hydroponic producers could select 5N-4.8P-21.6K and 5N-5.2P-21.6K fertilizers for the cultivation of the ‘Orangella’ cultivar of sweet pepper based on yield. It is important to evaluate more fertilizers and cultivars for eggplant hydroponic cultivation.

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 354〈/p〉 〈p〉Author(s): Junhui Chen, Qifeng Wu, Songhao Li, Jiangfei Ge, Chenfei Liang, Hua Qin, Qiufang Xu, Jeffry J. Fuhrmann〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Intensive forest management practices, such as fertilization, understory removal and deep tilling, play an important role in improving plant growth in forests through altering nutrient availability and soil structure. However, how such management affects soil microbial community diversity and functions related to nutrient cycling remains largely unknown. In this study, we investigated the responses of soil bacterial community composition and enzyme activities involved in C, N and P cycling to long-term intensive management, and identified the critical determinants that regulated them across a chronosequence of Moso bamboo forests (0, 10, 15, 20 and 25 years of intensive management) in subtropical China. Our results demonstrated that intensive management decreased soil pH and aggregation and increased mineral nutrient contents. Illumina MiSeq sequencing showed that significant (〈em〉P〈/em〉 〈 0.05) shifts of the soil bacterial community composition occurred after 15 years of management. Diversity indices (phylogenetic diversity, OTU richness and Chao1) generally decreased after 15 years of management. Soil pH, NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉-N, and available P and K contents were key factors shaping the bacterial community composition. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) predicted lower functional diversity of soil bacterial microbiomes as related to the cycling of amino acids and carbohydrates after 15 and 20 years. The activities of β-glucosidase and phosphatase decreased markedly after 15 years of intensive management, but rebounded after 25 years. Structural equation modeling provided evidence that the response of soil enzyme activities to forest management was mediated by changes in bacterial composition and diversity. Our study suggests that intensive forest management decreases microbial diversity indices and changed community composition, which could have direct consequences for soil functioning.〈/p〉〈/div〉 〈/div〉

Description: In soybean production, the shade avoidance response can affect yield negatively in both mono- and inter-cropping systems due to increased heterogeneity of the crop and lodging. This is mainly regulated by photoreceptors responding to the ratio between red and far-red light (R:FR) and photosynthetic photon flux density (PPFD). In this study, three soybean cultivars were grown under different R:FR and PPFD in a light emitting diode (LED) climate chamber to disentangle the effect of each on morphology and dry matter. Results showed that plant organs were influenced differently and indicated an interaction with the increase in assimilates at high PPFD. Internode elongation was mainly influenced by low PPFD with an additive effect from low R:FR, whereas petiole elongation responded strongly under low R:FR. Hence, petiole elongation can be seen as the main response to the threat of shade (high PPFD and low R:FR) and both petiole and internode elongation as a response to true shade (low PPFD and low R:FR). Interactions between cultivar and light treatment were found for internode length and diameter and leaf mass ratio, which may be unique properties for specific cropping systems.

Description: Future climatic conditions might have severe effects on grapevine architecture, which will be highly relevant for vineyard management decisions on shoot positioning, pruning or cutting. This study was designed to help gaining insight into how, in particular, increasing temperatures might affect grapevine canopies. We developed a functional-structural model for Riesling, Virtual Riesling, based on digitised data of real plants and a comprehensive state-of-the-art data analysis. The model accounts for the variability in temperature-sensitive morphological processes, such as bud break and appearance rates. Our simulation study using historical weather data revealed significant effects of the thermal time course over the year on bud burst of the cane and on primary shoots. High variabilities in these events affect canopy growth and leaf area distribution. This report shows that Virtual Riesling can be useful in assessing the significance of changing temperatures for grapevine architecture and thereby considering management techniques such as vertical shoot positioning. Further developments of Virtual Riesling might support the knowledge gain for developing necessary adaptations in future vineyard management and, thus, facilitate future work on climate change research using functional-structural model approaches.

Description: Intermediate wheatgrass (IWG, Thinopyrum intermedium, (Host) Barkworth & D.R. Dewey subsp. intermedium, 2n = 6x = 42) is a novel perennial crop currently undergoing domestication efforts. It offers remarkable ecosystem services and yields higher relative to other perennial grain crops. While IWG is mostly resistant to Fusarium head blight (FHB), identifying genomic regions associated with resistance will help protect the crop from potential disease epidemics. An IWG biparental population of 108 individuals was developed by crossing parents differing in their response to FHB and bacterial leaf streak (BLS). The population was screened for disease reaction over three years using isolates collected from IWG plants in St. Paul, Minnesota, USA. Linkage maps representing the 21 IWG chromosomes were constructed from 4622 Single Nucleotide Polymorphism (SNP) markers, with one SNP at every 0.74 cM. Interval mapping identified 15 quantitative trait loci (QTL) associated with FHB resistance and 11 with BLS resistance. Models with two or three QTL combinations reduced FHB disease severity by up to 15%, and BLS by up to 17%. When markers associated with FHB resistance were used as cofactors in genomic selection models, trait predictive ability improved by 24–125%. These genomic regions and genetic markers associated with FHB and BLS resistance can also be used to safeguard annual cereal grains through gene introgression and selective breeding.

Description: Water status controls plant physiology and is key to managing vineyard grape quality and yield. Water status is usually estimated by leaf water potential (LWP), which is measured using a pressure chamber; however, this method is difficult, time-consuming, and error-prone. While traditional spectral methods based on leaf reflectance are faster and non-destructive, most are based on vegetation indices derived from satellite imagery (and so only take into account discrete bandwidths) and do not take full advantage of modern hyperspectral sensors that capture spectral reflectance for thousands of wavelengths. We used partial least squares regression (PLSR) to predict LWP from reflectance values (wavelength 350–2500 nm) captured with a field spectroradiometer. We first identified wavelength ranges that minimized regression error. We then tested several common data pre-processing methods to analyze the impact on PLSR prediction precision, finding that derivative pre-processing increased the determination coefficients of our models and reduced root mean squared error (RMSE). The models fitted with raw data obtained their best results at around 1450 nm, while the models with derivative pre-processed achieved their best estimates at 826 nm and 1520 nm.

Description: Low prices have prompted growers to contemplate transitioning to an organic system. We evaluated red clover-maize-soybean-wheat (Cl-M-S-W), maize-soybean (M-S-M-S), and soybean-wheat/red clover-maize-soybean (S-W/Cl-M-S) rotations in organic and conventional systems in New York, USA from 2015 to 2018 to identify profitable organic practices. Organic compared with conventional maize in 2017 had 14.6% higher yield and $2107/ha higher returns above selected costs in the S-W/Cl-M-S rotation; and had $1007/ha higher returns in the M-S-M-S rotation, despite 3.6% lower yield and higher production costs, because of the organic price premium. Likewise, organic compared with conventional soybean had ~$800 to ~$900/ha higher returns in 2017 and 2018, despite ~10% lower yield and ~$50/ha higher production costs, because of the organic price premium. Organic compared with conventional wheat yielded ~4% higher with $125/ha higher returns, despite ~$435/ha higher production costs. Organic compared with the conventional system had $1018/ha higher returns in the Cl-M-S-W rotation, $1782/ha higher in the M-S-M-S rotation, and $2961/ha higher in the S-W/Cl-M-S rotation in 2017 and 2018. Although returns in 2015 and 2016 (no organic premium) were lower, the organic compared with the conventional system from 2015 to 2018 had $673/ha higher returns in the Cl-M-S-W rotation, $497/ha higher in the M-S-M-S rotation, and $2355/ha higher in the S-W/Cl-M-S rotation indicating that the S-W/Cl-M-S rotation was the most profitable organic rotation during the four-year period.

Description: Cymbidium faberi Rolfe is a very popular potted plant in China, Japan and Korea where it has been cultivated for centuries. The economic value of this popular native Asian orchid could be enhanced by changes in its floral traits. In Arabidopsis, PISTILLATA (PI) is involved in regulating petal and stamen development. In order to investigate the possible role of the PI ortholog involved in floral development, we isolated CyfaPI from C. faberi. Protein alignment and a phylogenetic tree grouped CyfaPI in the PI lineage. CyfaPI transcripts were detected in all floral organs, but were absent in leaves. Moreover, in flowers, the highest expression level of CyfaPI was present in the gynostemium and the lowest level was found in anther caps. In addition, ectopic expression of CyfaPI in Arabidopsis pi-1 mutant rescued petal development, and complement the development of filament-like structure (part of stamen), but failed to complement anther development in the stamen whorl. All these finding suggest that CyfaPI is mainly responsible for perianth and gynostemium development in C. faberi. Our data may help to trace the development of the gynostemium program and evolution in orchids.

Description: This study was conducted to evaluate the effects of Bradyrhizobium japonicum SAY3-7, Bradyrhizobium elkanii BLY3-8, and Streptomyces griseoflavus P4 on the symbiotic effectiveness of soybeans before biofertiliser production, to produce biofertiliser containing the studied three strains (SAY3-7, BLY3-8, and P4), to test the effectiveness of the biofertiliser on soybean varieties, and to assess the varietal effects and interaction effects between variety and biofertiliser on plant growth, nodulation, nitrogen fixation, nutrient absorption, and seed yield. Nitrogen fixation was measured using the acetylene reduction assay and ureide methods. Contents of nutrients (N, P, K, Ca, and Mg) were also measured to calculate their uptakes. In this study, synergistic effects of nitrogen fixation were induced by combined inoculation with SAY3-7, BLY3-8 and P4 in all tested soybean varieties. Therefore, we assumed that an effective biofertiliser could be produced using these effective bacteria (SAY3-7, BLY3-8, and P4). After making biofertiliser using these effective bacteria, packages were stored at 30 °C. The populations of the bacteria in the biofertiliser were maintained at a density of 1 × 108 colony forming units (cfu) g−1 for P4 and 7 × 109 cells g−1 for Bradyrhizobium. Diluting biofertiliser by 10−3 proved more effective for nodulation and nitrogen fixation than other dilution treatments. Moreover, this biofertiliser significantly promoted plant growth, nodulation, nitrogen fixation, nutrient uptakes, and seed yield in Yezin-3 and Yezin-6 soybean varieties. Yezin-6 is a more efficient variety than Yezin-3 for improved plant growth, nodulation, nitrogen fixation, nutrient absorption, and seed yield. Taken together, the application of an effective biofertiliser and the use of an efficient soybean variety can play important roles in promoting plant growth, nodulation, nitrogen fixation, and higher seed yield.