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Land-use changes could potentially exert a strong influence on soil quality and soil microbial communities. Moreover, microbial taxa are also important drivers of soil ecological functions. However, the linkage between soil quality and soil microbial communities is in need of deeper understanding. In this study, we examined the effects of soil quality on microbial community structure and functions after forest conversion to vegetable cropland and tea plantations. Soil quality index was significantly increased after natural forest conversion to vegetable cropland and tea plantations. Soil bacterial beta diversity significantly correlated to soil quality, but the sensitivity of individual microbial groups varied in response to changes in soil quality. Higher soil quality promoted bacterial diversity in vegetable cropland but decreased it in tea plantations, which implied soil quality was a structural factor in bacterial community composition but had contrasting effects for croplands versus plantations. Agricultural management played a negative role in maintaining microbial interactions, as identified by the network analysis, and furthermore the analysis revealed key functions of the microbial communities. After land-use change, the abundance (e.g., level, intensity) of microbial N-cycling function increased in tea plantations but decreased in vegetable cropland. The abundance of C-cycling function featured an opposite trend. Higher level of N-fixation in tea plantations but the higher abundance of N-oxidation in vegetable cropland was demonstrated. Higher abundance of ammonia-oxidizing bacteria and ammonia-oxidizing archaea as identified by qPCR in vegetable cropland corroborated the FAPROTAX function prediction. Therefore, the key taxa of soil microbial communities and microbial functions were largely dependent on changes in soil quality and determined responses to specific agricultural management.

Soil aggregates provide microhabitats for microorganisms. However, the bacterial communities within various aggregate size fractions under organic amendments have rarely been evaluated especially in sandy soils. A field experiment involving addition of biogas residue (BR), pig manure (PM), biochar (BC), and straw (ST) of a sandy soil was performed to determine the structure of the bacterial community in aggregate size fractions by using high‐throughput sequencing. We found that organic amendments change soil aggregate fractions and nutrient content, alter bacterial diversity and composition, and contribute to the predicted bacterial functions. The BR increased bacterial α‐diversity in 0.25‐mm aggregates. The BC treatment decreased the bacterial α‐diversity in the 0.053‐mm aggregates. Collectively, the effects of organic amendments on the bacterial community varied greatly depending on type of amendments and aggregate size. The BR supported highly diverse bacterial taxa in the

Our previous report described that high-pressure microfluidization (HPM) treatment can disaggregate peanut protein isolates (PPIs) to prepare antihypertensive peptide fractions. In the present study, we investigated the driving forces of disaggregation and reaggregation of PPIs in aqueous dispersion induced by HPM treatment and discussed the mechanism. The driving forces of hydrogen bonds, surface hydrophobicity, sulfhydryl/disulfide bonds (SH/SS) and ζ-potential, which are responsible for disaggregation and reaggregation, were studied. HPM treatment changed the polar environment and promoted surface hydrophobicity and the formation of disulfide bonds (SS), while the free sulfhydryl (SH) group content was decreased. The magnitude of the ζ-potential and β-sheet content increased when the pressure was ≤120 MPa. However, the magnitude of those values decreased when the pressure was >120 MPa. Hydrophobic interactions, SH/SS interchange reactions, hydrogen bonds and electrostatic interactions cannot individually induce changes in PPIs. Combination of the applied forces drove the disaggregation and reaggregation of PPIs in aqueous dispersion.

Large quantities and many varieties of agricultural organic wastes are produced in China annually. Applying agricultural organic wastes to soil plays an essential role in coping with the environmental pollution from agricultural wastes, solving the energy crisis and responding global climate change. But there is little information available on the effects of different agricultural organic wastes on soil greenhouse gas (GHG) emissions. The objectives of this study were to investigate and compare the impacts of different organic wastes on soil GHG emissions during a 4-year field experiments in the North China Plain, as well as analyze the influential factors that may be related to GHG emissions. The treatments were: crop straw (CS), biogas residue (BR), mushroom residue (MR), wine residue (WR) and pig manure (PM) returning to soil, as well as a control with no organic waste applied to soil but chemical fertilizer addition only (CF). The results showed that compared with CF treatment, organic material applied to soil significantly increased GHG emissions and emissions followed the order of WR(27,961.51 kg CO2-eq/ha/yr) > PM(26,376.50 kg CO2-eq/ha/yr) > MR(23,366.60 kg CO2-eq/ha/yr) > CS(22,434.44 kg CO2-eq/ha/yr) > BR (22,029.04 kg CO2-eq/ha/yr) > CF(17,402.77 kg CO2-eq/ha/yr), averagely. And considering the affecting factors, GHG emissions were significantly related to soil temperature and soil water content. Different organic wastes also affected soil total organic carbon (TOC), microbial carbon (MBC) and dissolved organic carbon (DOC) contents, which related to GHG emissions. Further analysis showed that characteristics of organic wastes affected GHG emissions, which included C-N ratio, lignin, polyphenol, cellulose and hemicellulose. Our study demonstrates that biogas residue returning to soil emitted minimum GHG emissions among these different types of organic wastes, which provided a better solution for applying organic wastes to mitigate soil GHG emissions.

To address the low productivity of sandy farmlands, our study aimed to conduct a comparative study on the effects of different organic amendment (OA) inputs for the potential improvement of crop yield and soil quality in sandy alkaline farmlands through the selection of a suitable OA. This study set up straw (ST) returning as control and chemical fertilizer (CF) treatment as a side control, and chose three OAs returning as treatments, including pig manure (PM), biogas residue (BR), and straw biochar (BC), for improving soil fertility, with all amendments having matched doses of nitrogen (N). The experiment was conducted at the Wuqiao Experimental Station (37&deg, 41 N, 116&deg, 37 E) of China Agricultural University in Hebei Province, China, from October 2012 to September 2016. The cropping rotation was the winter wheat (Triticum aestivum L.)-summer maize (Zea mays L.) rotation system. Through a consecutive four-year field experiment, the principal results showed that three types of OA application significantly increased soil organic carbon from 1.46 g kg&minus, 1 to 8.24 g kg&minus, 1, soil total N from 0.21 g kg&minus, 1 to 0.64 g kg&minus, 1, soil available potassium from 55.85 mg kg&minus, 1 to 288.76 mg kg&minus, 1, and soil available phosphate from 4.86 mg kg&minus, 1 to 65.00 mg kg&minus, 1 in the 0&ndash, 20 cm soil layer. The BR was the most effective in improving soil nutrients as compared with the ST. The PM and BR treatments were more conducive to promoting crop yield by 6&ndash, 20% than ST, and the BC treatment significantly reduced the yield of winter wheat by 19% and summer maize by 8%. As the BR and PM treatments improved the soil nutrient content and significantly increased crop yield, these were the top choices for transforming the low-yield sandy farmlands.

The enhanced yield of summer maize depends not only on soil water, but also on plant nutrition and fertilization with sulfur, a key element, which plays an important role in improving yield and water use. However, no research has focused on the coupling effects of sulfur application and irrigation patterns from anthesis to maturity on summer–maize grain yield and water use. We tested three irrigation patterns: no irrigation after anthesis (W0), irrigation at 15 days after anthesis (W1), and irrigation at 15 and 30 days after anthesis (W2), either combined with sulfur (S1, elemental sulfur) or without sulfur (S0) to evaluate the soil moisture content (SMC), grain yield, and water utilization of summer maize in a rainout shelter during the 2016 and 2017 growing seasons, in the North China Plain. Sulfur application reduced the SMC at 0–20 cm irrespective of irrigation pattern at harvest, but increased it at 30–120 cm while reducing evapotranspiration under W1 and W2. Compared to W0, W1 and W2 treatments significantly increased aboveground biomass (10.9% and 21.9% in 2016; 20.4% and 31.7% in 2017, respectively) and grain yield (16.1% and 26.2% in 2016; 24.6% and 35.3% in 2017, respectively). Water productivity at the grain yield level (WPy) increased with sulfur application by 6.4%, 8.8%, and 7.6% in 2016, and by 4.3%, 7.9%, and 6.4% in 2017 under W0, W1, and W2 conditions, respectively. The results indicated that sulfur application enhanced WPy, increased grain yield of summer maize. Thus, combining post-anthesis irrigation with sulfur application should be recommended for attaining high WPy and yield of summer maize in the North China Plain.

To effectively improve soil productivity and optimize organic fertilizer management while reducing environmental pollution and resource wasting in farmland system, the present study was conducted in Wuqiao Experiment Station of China Agricultural University, Hebei Province. Taking crop straw treatment as control, four kinds of organic materials including pig manure (PM), biogas residue (BR), biochar (BC) and crop straw (ST) were applied to soil at the same nitrogen (N) level. The soil bacteria community characteristics were explored using Illumina Miseq high-throughput sequencing technologies. The results were as follows: (1) Compared with ST, PM, BR and BC had no significant effect on Chao 1 and Shannon index. The dominant bacterial groups include Proteobacteria, Acidobacteria, Actinobacteria, Bacteroidetes, and Chloroflexi in sandy loam soil after the application of different organic materials. The abundance of Proteobacteria in BC treatment was significantly lower than that of ST (control) treatment (p

In recent years, China has developed a series of disposal methods and corresponding recycling systems to deal with agricultural wastes, as well as to mitigate climate change. The objective of this paper is to evaluate the net greenhouse gas emissions (NGHGE) and crop yields of three types of typical recycling systems, based on case studies in the North China Plain. These systems are the CC system, “crop production-crop production” by returning crop straw to the soil; CPC system, “crop production-pig rearing-crop production” by returning pig manure to the soil; and the CPBC system, “crop production-pig rearing-biogas production-crop production” by returning biogas residue to the soil. The overall results show that a reduction of 15.18% in NGHGE was achieved with the CPC system compared with a system where no pig manure was returned to the soil. NGHGE of CPBC system achieved a reduction of 352.25% compared with no biogas being produced and no pig manure being returned. These results imply that the development of recycling agriculture, i.e., manure reuse and biogas production, is a superior method to reduce GHG emissions. Additionally, compared with CC system, crop yields improved by 17.75% and 18.68% in the CPC and CPBC systems, respectively, which is an important factor in guaranteeing food security. Therefore, compared with non-recycling practices, by reusing organic wastes, these recycling systems reduced the total GHG emissions and increased crop yields. Accordingly, agricultural recycling offers a promising system for dealing with large volumes of waste, responding to global climate change, and ensuring food security in China.

The maize sole cropping system solves problems related to ground water resource shortages and guarantees food security in the North China Plain. Using optimal sowing dates is an effective management practice for increasing maize yield. The goal of this study was to explore an optimum sowing date for high-yield maize. Six sowing dates (SDs) from early April to late June with intervals of 10 to 20 days between SD—SD1 (early April), SD2 (mid to late April), SD3 (early May), SD4 (mid to late May), SD5 (early June), SD6 (late June)—were applied from 2012 to 2017. The results showed that yield was correlated with the sowing date based on the thermal time before sowing (r = 0.62**), which was defined as the pre-thermal time (PTt), and that the yield was steadily maintained at a high level (&gt, 10,500 kg ha−1) when PTt was greater than 479 °C. To satisfy the growing degree-days required for maturity, maize needs to be sown before a PTt of 750 °C. Data analysis of the results from 2014, 2015, and 2017 revealed the following: i) Most of the grain-filling parameters of late-sown dates (SD4, SD5 and SD6) were better than those in early-sown dates (SD1, SD2, and SD3) in all years, because of the high daily maximum temperature (Tmax) and wide diurnal temperature (Td) from silking to blister (R1–R2) of early-sown dates. The weight of maximum grain-filling rate (Wmax) of SD3 decreased compare with SD4 by the narrow Td from blister to physiological maturity (R2–R6) in all years (−5, −12, and −33 mg kernel−1 in 2014, 2015, and 2017, respectively). ii) In 2017, the pollination failure rates of early-sown dates were 8.4~14.5%, which was caused by the high Tmax and Td of R1–R2. The apical kernel abortion rates were 28.6 (SD2) and 38.7% (SD3), which were affected by Tmax and Td during R2–R6. iii) Compared with late-sown dates, the wide Td of early-sown dates in R1–R2 was caused by higher Tmax, but the narrow Td in R2-R6 was caused by higher Tmin. Our results indicate that high-yielding maize can be obtained by postponing the sowing date with a PTt of 480~750 °C, which can prevent the negative effects of the high Tmax of R1–R2 and high Tmin of R2–R6 on kernel number and weight formation. Moreover, these above-mentioned traits should be considered for heat tolerance breeding to further increase the maize yield.

The policy of land rental activity from fragmented to concentrated farmland has been overwhelming encouraged by the Chinese government. The land management policy has paid more attention on the investigation of its economic and social performances of land rental activity, while information on its environmental consequence is still lacking. This study, therefore, compared the environmental and economic performances of small (SF) and large scale (LF) farms based on emergy evaluation (EME), life cycle assessment (LCA) methods, and economic analysis (EA), which reflected a land rental activity from fragmented to concentrated farmland in the North China Plain (NCP). The EME results showed that the environmental loading ratio of the LF was 5.0% lower, while the emergy yield ratio and emergy sustainability index of the LF were 1.48% and 8.0% higher, respectively, than that of the SFs. The LCA results demonstrated that the area-based and yield-based environmental impact indices of the LF were 28.8% and 18.3% lower than that of the SF, respectively. These results indicate that the environmental consequences of the cropping system were improved when the farmland was managed in a concentrated model instead of a fragmented model. In addition, the EA results showed that the income to cost ratio of the LF was reduced by 47.46% compared to that of the SF, due to high land rental costs in the LF. Nevertheless, the total profit of the LF was 1719.3% higher than that of the SF due to its lager farm scale. Also, the owner's total profit of the SF was increased by 195.5% compared to the farming by themselves in their own farmland instead of renting them out. These results showed that scale management can promote both managers who rented out and into the farmland to increase their annual total incomes. In conclusion, the concentrated farmland would be a platform for the improvement of environmental consequences of cropping systems in the NCP.

Soil microorganisms are the core force driving the conversion of plant residues into soil organic carbon (SOC). Identifying the changes in soil microorganism responses to tillage practices is a key step in understanding the SOC sequestration potential. The aim of this study is to assess the impacts of different tillage practices on microbial communities and functions in agricultural soils. A field experiment involving no tillage (NT), rotary tillage (RT), and deep tillage (DT) in winter wheat-summer maize double cropping was performed to determine the structure of the microbial community and its functions using metagenomics. We found that tillage practices changed the composition of soil microbial communities and their functions related to the C cycle. The relative abundance of fungi in DT was significantly higher than that of the NT and RT treatments and primarily facilitated the growth of the fungi community. Moreover, DT treatment increased the relative abundance of genes involved in carbohydrate transport and metabolism genes and carbohydrate metabolism pathway genes, in addition to those encoding carbohydrate-binding modules. Therefore, we concluded that DT increases the transformation potential of straw-C to SOC in the North China Plain where large amounts of wheat and maize straw are returned to the field every year.

Monocropping systems, which currently dominate China&rsquo, s major grain production regions, contribute to resource scarcity and environmental pollution. Intercropping has the potential to improve resource use efficiency. However, prior studies of intercropping systems have generally focused on ecological, economic, and social consequences. Here, we make a comparative ecological sustainability analysis on energy capture and efficiency of maize monocropping and maize&ndash, soybean intercropping systems through emergy evaluation based on field experiments performed from 2012 to 2014. We find that maize monocropping shows higher sustainability than maize&ndash, soybean intercropping in the North China Plain at present. Quantitative results indicate that for maize monocropping, the emergy yield ratio (EYR) and emergy sustainability index (ESI) are 13.7% and 21.1% higher than that of intercropping systems, and the environmental loading ratio (ELR) is 7.3% lower than that of intercropping systems. To further test, we applied three levels of nitrogen fertilizer in intercropping systems (120 kg ha&minus, 1, 180 kg ha&minus, 1, 240 kg ha&minus, 1), and find that a reduced rate of N fertilizer for intercropped system leads to higher sustainability (ESI 5.3% higher) but still lower sustainability than maize monocropping. Key drivers of the different sustainability outcomes are decreased energy output and a larger proportion of labor input associated with intercropping systems.