ALBERT

Description: 〈p〉Publication date: Available online 5 August 2017〈/p〉 〈p〉〈b〉Source:〈/b〉 Pedosphere〈/p〉 〈p〉Author(s): Beata Klimek, Marcin Chodak, Małgorzata Jaźwa, Hamed Azarbad, Maria Niklińska〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The aim of this study was to assess and to detect factors controlling the temperature sensitivity of soil organic matter (SOM) in boreal forests, constituting an important stock of carbon. Soils were collected under Scots pine, Norway spruce, silver birch and mixed forests (O horizon) in northern Finland and measured for basal respiration rate at five different temperatures (from 4°C to 28°C). Q〈sub〉10〈/sub〉 values were calculated using a Gaussian function and based on temperature-dependent changes. The soils were measured for the a range of physicochemical parameters and functional diversity of soil microbial communities was assessed using the novel MicroResp™ method. Temperature sensitivity of SOM decomposition differed under the studied forest stands, with pine forests exhibiting the highest temperature sensitivity of SOM decomposition at a lower temperature range (0°C – 12°C). In such temperature range we found that Q〈sub〉10〈/sub〉 values were positively correlated with microbial functional diversity index (H’〈sub〉mic〈/sub〉) and soil C-to-P ratio. These suggest that metabolic abilities of soil microbial communities and soil nutrient content are the important controls of temperature sensitivity of taiga soils.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 5 August 2017〈/p〉 〈p〉〈b〉Source:〈/b〉 Pedosphere〈/p〉 〈p〉Author(s): Afsana Praveen, Chandana Pandey, Ehasanullah Khan, Medha Panthri, Meetu Gupta〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Arsenic (As), one of the most harmful toxicant at global level severely affects plant metabolism when taken up. Interestingly, presence of silicon (Si) as fertilizer in As-contaminated soil is an effective strategy to decrease As accumulation in the plants. 〈em〉Brassica juncea〈/em〉 (var. Varuna) were grown hydroponically to investigate the role of Si at biochemical and molecular levels under arsenite [As〈sup〉III〈/sup〉] stress. Seedlings of 〈em〉B. juncea〈/em〉 were exposed to As〈sup〉III〈/sup〉 (150 µM), Si (1.5 mM) and a combination of both the elements. Our data demonstrated that seedlings exposed to As〈sup〉III〈/sup〉 showed an inhibition in shoot length, chlorophyll, carotenoid and protein while co-application of Si improved these growth parameters. Si supplementation has reduced the As accumulation in shoot. Increase/decrease was observed in stress related parameters (cysteine and proline), antioxidant enzymes (SOD, CAT and APX) and oxidative stress markers (MDA and H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉), which were improved on co-application of Si as compared to As〈sup〉III〈/sup〉 treatment. RAPD is a suitable biomarker assay for plants for assessing the genotoxicity. Seven primers used in RAPD produced a total of 39 and 48 bands in the leaves of control and treated seedlings, respectively. RAPD band-profiles and genomic template stability (GTS) were consistent with other growth and physiological parameters. In conclusion, the genotoxic alterations along with the biochemical parameters indicate that the exposure to Si mitigates As〈sup〉III〈/sup〉 induced oxidative stress by improving stress related parameters and antioxidant system in 〈em〉B. juncea.〈/em〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 5 August 2017〈/p〉 〈p〉〈b〉Source:〈/b〉 Pedosphere〈/p〉 〈p〉Author(s): Jun YAN, Xiao Zeng HAN, Wen Feng CHEN, En Tao WANG, Wen Xiu ZOU, Zhi Ming ZHANG〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Aiming to maintain and recover the productivity of Chinese Mollisol, a long-term fertilization experiment has been carried out for 29 years under the wheat-maize-soybean rotation system, including application of ROM (recycled organic manure), chemical fertilizers and their combinations. The effects of different treatments were evaluated by determining the soil physicochemical features, soybean production and soybean rhizobial diversity. The results showed that application of recycled organic manure (ROM)-combined with chemical fertilizer maintained or increased soil fertility, companying by higher production and higher diversity of soybean rhizobia. The negative association of 〈em〉Bradyrhizobium japonicum〈/em〉 with N-fertilizer, positive association of 〈em〉B. diazoefficiens〈/em〉 with soil acidification, and reducing of N-impression on the diversity of 〈em〉Bradyrhizobium〈/em〉 by addition of ROM were recorded as new findings. Therefore, the ROM involved treatments, especially NPK+ROM could be a feasible strategy for maintaining and recovering the fertility of the Chinese Mollisol, while the rhizobial diversity could be an indicator for the soil fertility.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 5 August 2017〈/p〉 〈p〉〈b〉Source:〈/b〉 Pedosphere〈/p〉 〈p〉Author(s): Lin Chen, Xiuli Xin, Jiabao Zhang, Marc Redmile-Gordon, Guangsen Nie〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Modern breeding primarily targets the traits of crop yield and is likely to influence the root-associated microbiomes which play significant roles in plant growth and health. The relative importance of soil and cultivar factors in shaping the root-associated microbiomes of modern maize remains uncertain. We conducted a pot experiment in a controlled environment using three soils (Mollisol, Inceptisol and Ultisol) and four contrasting cultivars which are widely planted in China (Denghai 605, Nonghua 816, Qiaoyu 8 and Zhengdan 958). We applied 16S rRNA gene amplicon sequencing to characterize the bacterial communities in the bulk soil, rhizosphere and endosphere. Our results showed that the four cultivars had different shoot biomass and root exudation levels. The microbiomes in the bulk soil, rhizosphere and endosphere were different. We observed the apparent community divergence between soils rather than cultivars, thereinto, edaphic factors substantially contributed to microbiome variation. Moreover, permutational multivariate analysis of variance corroborated significant contributions of soil type but not cultivar on the root-associated microbiome structure. Differential abundance analysis confirmed that each soil presented a distinct root microbiome, while network analysis indicated different co-occurrence patterns of the root microbiome among the three soils. The core root microbiome members are implicated in plant growth promotion and nutrient acquisition in the roots. In conclusion, the root-associated microbiomes of modern maize are much more controlled by soil characteristics than by cultivar root exudation. Our study is anticipated to help contribute to improved breeding strategies through integrative interactions of soils, cultivars and their associated microbiomes.〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Pedosphere, Volume 28, Issue 4〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: Available online 1 August 2017〈/p〉 〈p〉〈b〉Source:〈/b〉 Pedosphere〈/p〉 〈p〉Author(s): Abideen Zainul, Hans-Werner KOYRO, Bernhard HUCHZERMEYER, Bilquees GUL, M. Ajmal KHAN〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil water and nutrient status both are of major importance for the plant appearance and its growth performance. The objective of this research was therefore to study the effect of biochar (1.5% BC) and a biochar-compost mixture (1.5% BC + 1.5% Co) on the performance of 〈em〉Phragmites karka〈/em〉 plants grown in a nutrient poor sandy clay (control, 50% sand 30% clay and 20% gravel) soil. The indicators of plant performance such as growth, lignocellulosic biomass, water relations, mineral nutrition status, leaf gas exchange, chlorophyll fluorescence parameters of 〈em〉P. karka〈/em〉, as well as soil respiration activity, were assessed. The sole amendment of BC led to higher growth rate and lignocellulosic biomass production in 〈em〉P. karka〈/em〉 plants compared to the non-treated control. There was also significant increase in soil respiration with biochar treatments that stimulated microbial interaction. The increase in the water holding capacity after BC amendment caused a significant improvement in plant water status (water potential, osmotic potential, leaf turgidity) and plant ion content (K〈sup〉+〈/sup〉, Mg〈sup〉++〈/sup〉 and Ca〈sup〉++〈/sup〉) leading to an increase of net photosynthesis but also a higher energy use efficiency of the Photosystem II. Additionally, the BC plants managed to avoid oxidative stress, improved water use efficiency (WUE) and decreased dark respiration. However, the amendment of a biochar-compost mixture (BC + Co) led to even better improvement of physiological parameters such as growth, leaf turgor, photosynthesis and nutrient content and soil gas exchange of 〈em〉P. karka〈/em〉. Our results suggested that BC and Co promote plant growth with respect to nutrient uptake, water balance, and efficiency of the photosynthetic system. In summary both soil amendments might open an opportunity for 〈em〉P. karka〈/em〉 to sequester CO〈sub〉2〈/sub〉 and to produce higher fodder, bio-active compounds and biomass for bio-energy on nutrient poor degraded soils.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 5 August 2017〈/p〉 〈p〉〈b〉Source:〈/b〉 Pedosphere〈/p〉 〈p〉Author(s): Yuan LIU, Zhong-yi LI, Ren-kou XU〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The manganese(II) [Mn(II)] forms on soybean roots were investigated to determine the main factors affecting the distribution of Mn(II) forms and the relationship with Mn(II) plant toxicity. Fresh roots of soybean obtained from solution culture experiments were reacted with Mn(II) in solutions, and then the Mn(II) adsorbed on soybean roots was differentiated into exchangeable, complexed and precipitated forms through sequentialextraction with KNO〈sub〉3〈/sub〉, EDTAand HCl. Results indicated thatthe exchangeable Mn(II) on soybean roots occupied the largest proportion, followed by the complexed Mn(II) and precipitated Mn(II) occupied the least proportion. Mn(II) toxicity to soybean roots was greater at pH5.5 than at pH4.2 due to the larger amount of exchangeable Mn(II) at higher pH. The cations Al〈sup〉3+〈/sup〉, La〈sup〉3+〈/sup〉, Ca〈sup〉2+〈/sup〉, Mg〈sup〉2+〈/sup〉 and NH〈sub〉4〈/sub〉〈sup〉+〈/sup〉competed with Mn〈sup〉2+〈/sup〉 for cation exchange sites on root surfaces, thus reduced the exchangeable Mn(II) on rootswith the order of Al〈sup〉3+〈/sup〉 and La〈sup〉3+〈/sup〉 〉 Ca〈sup〉2+〈/sup〉 and Mg〈sup〉2+〈/sup〉 〉 NH〈sub〉4〈/sub〉〈sup〉+〈/sup〉. Al〈sup〉3+〈/sup〉 and La〈sup〉3+〈/sup〉 at 100μmol L〈sup〉−1〈/sup〉decreased the exchangeable Mn(II)by 80 and 79%, respectively, and Ca〈sup〉2+〈/sup〉 and Mg〈sup〉2+〈/sup〉at 1mmol L〈sup〉−1〈/sup〉 reduced the exchangeable Mn(II) on soybean roots by 51 and 73%, respectively. Organic anions reduced the concentration of free Mn〈sup〉2+〈/sup〉 in solution through formation of complexes with Mn〈sup〉2+〈/sup〉, and thus efficiently decreased the exchangeable Mn(II) on plant roots. Oxalate, citrate and malate decreased the exchangeable Mn(II) on soybean roots by 30.9, 19.7 and 10.9 %, respectively, which was consistent with thecomplexing abilityof these organic anions with Mn(II).It can be concluded that exchangeable Mn(II) was the dominant form of Mn(II) on soybean roots and was responsible for Mn(II) toxicity to plants. The coexisting cations and organic anions reduced the exchangeableMn(II).〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Pedosphere, Volume 28, Issue 4〈/p〉 〈p〉Author(s): Qifa ZHOU, Benjamin A. HOUGE, Zhaohui TONG, Bin GAO, Guodong LIU〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Application of biochar to agricultural soils is effective to sequester atmospheric carbon and improve soil quality, but current pyrolysis and transportation costs are high, making biochar too costly to be used at the field scale. This study developed a new 〈em〉in-situ〈/em〉 technique, burning and soil covering (B-SC), which can be used by farmers for production of biochar with crop residue. In this study, the air-dried feedstocks, elephant grass and corn residue, were burnt 〈em〉in situ〈/em〉 for biochar production in the field. After approximately 90% of the leaves were combusted, the burning process was dramatically slowed down by covering the feedstock with soil. The biochar yield averaged 18.0 ± 1.3 (〈em〉n =〈/em〉 15) and 13.7 ± 1.3 (〈em〉n〈/em〉 = 10) kg per 100 kg air-dried feedstock for the elephant grass and corn residue, respectively. The biochar properties were suitable for soil improvement. The inputs for biochar production of the B-SC process only included low labor force, open field, feedstock (〈em〉e.g.,〈/em〉 grass and crop residue), and simple tools. The operation time for processing 10 kg of the corn residue by an individual farmer was 24.4 ± 4.1 min (〈em〉n〈/em〉 = 10). As compared with the conventional field burning process, the B-SC process drastically shortened the time for biomass burning and generated a significantly lower emission of smoke and thermal energy. This simple technique can be particularly practical and effective for farmers to improve the soils of poor quality in China.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 5 August 2017〈/p〉 〈p〉〈b〉Source:〈/b〉 Pedosphere〈/p〉 〈p〉Author(s): Elena OKADA, José Luis COSTA, Francisco BEDMAR〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Glyphosate is the most used herbicide in Argentina, accounting for 62% of the commercialized pesticides in the market. It is used as a weed controller in no-till systems, and it is also applied in various genetically modified crops (e.g. soybean, corn, cotton). Though it has a high solubility in water, it tends to adsorb and accumulate in agricultural soils. The main objectives of this work were to compare the dissipation of glyphosate and the accumulation of its metabolite aminomethylphosphonic acid (AMPA) over time in three soils from agricultural areas of Argentina, under long-term management of no-till (NT) and conventional tillage (CT) practices. Forty percent of the applied glyphosate was degraded within the first three days in all soils, indicating a fast initial dissipation rate.〈/p〉 〈p〉However, the dissipation rate considerably decreased over time and the degradation kinetics followed a two-compartment kinetic model. No differences were found between tillage practices. Dissipation was not related to the microbial activity measured as soil respiration. The fast decrease in the concentration of glyphosate at the beginning of the dissipation study was not reflected in an increase on the concentration of AMPA. The estimated half-lives for glyphosate ranged between 9 and 38 days. However, glyphosate bioavailability decreases over time as it is strongly adsorbed to the soil matrix. This increases its residence time which may lead to its accumulation in agricultural soils.〈/p〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Pedosphere, Volume 28, Issue 6〈/p〉 〈p〉Author(s): Yandong MA, Jingbo ZHAO, Rui LIU, Qi ZHOU, Leipeng YIN〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Permeability and water-bearing space are important hydrological characteristics of the loess strata. In this study a systematic experiment was conducted to measure the magnetic susceptibility, grain size, porosity, and infiltration rate of the loess and palaeosol layers on a loess tableland of the central Chinese Loess Plateau, in order to investigate the differences in hydrological conditions between the loess and palaeosol layers. The magnetic susceptibility of the loess layer was lower than that of the palaeosol layer, but the average quasi-steady infiltration rate was about 0.31 mm min〈sup〉−1〈/sup〉 higher, the coarse silt and very fine sand contents were about 7.1% greater, and the porosity was about 5.7% higher. These differences were mainly due to pedogenesis, which was affected by the Quaternary climate. The pedogenesis differences between the loess and palaeosol layers resulted in hydrological property differences in terms of permeability and water-bearing space. The loess layer had a higher permeability and more water-bearing space than the palaeosol layer, which meant that the loess layer is more likely to form aquifers and the palaeosol layer is more prone to form aquitards. The groundwater in the loess strata had a multilayered characteristic, which depended on the relative impermeability of palaeosol layer and the alternate deposition of loess-palaeosol layers. The hydrological characteristics of the loess strata demonstrated that the Quaternary climate had an important control function on the formation and movement of groundwater. This knowledge provides a reliable theoretical basis for water resource development and utilization on the Chinese Loess Plateau, and this study extends the application of Quaternary climate change theory to hydrological systems in loess deposits.〈/p〉〈/div〉