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Existing agricultural nitrogen datasets in China are mostly developed using coarse national or provincial statistics. A crop‐specific nitrogen rate dataset based on the finest‐scale agricultural nitrogen statistics at the county level remains lacking. Here, we constructed a new dataset (CN‐N), which provides annual nitrogen rates for rice, wheat and maize in China at a 1‐km spatial resolution from 2004 to 2016. This dataset was developed by harmonizing county‐level and provincial agricultural nitrogen statistics with gridded crop distribution maps, resulting in 13 years of nitrogen rate maps for each crop covering 2004–2016. Validation against farmers' surveys by crop indicates CN‐N reliably quantifies average nitrogen rates and trends for each crop over 2004–2016, demonstrating improved spatial heterogeneity compared to previous datasets rasterized using only provincial statistics. Our study provides a crop‐specific, temporally consistent, gridded nitrogen rate dataset based on the finest‐scale county‐level agricultural nitrogen statistics. This can support future process‐based modelling for sustainable agricultural nitrogen management strategies. [ABSTRACT FROM AUTHOR]

The oriental armyworm, Mythimna separata (Walker), an important migratory pest of maize and wheat, is posing a severe threat to maize production in Asian countries. As source areas of spring–summer emigratory populations, the control of M. separata in southwestern China is of great significance for East Asian maize production. To assess the toxicity of Bt maize against the pest, bioassays of Bt-(Cry1Ab+Vip3Aa) maize (event DBN3601T), Bt-Cry1Ab maize (event DBN9936), and Bt-Vip3Aa maize (event DBN9501) were conducted in Yunnan province of southwest China. There were significant differences in insecticidal activity between the three Bt maize events, and DBN3601T presented the highest insecticidal role. The results also indicated that the insecticidal effect of various Bt maize tissues took an order in leaf > kernel > silk, which is highly consistent with the expression amounts of Bt insecticidal protein in leaf (69.69 ± 1.18 μg/g), kernel (11.69 ± 0.75 μg/g), and silk (7.32 ± 0.31 μg/g). In field trials, all larval population densities, plant damage rates, and leaf damage levels of DBN3601T maize were significantly lower than the conventional maize. This research indicated that the DBN3601T event had a high control efficiency against M. separata and could be deployed in southwest China for the management of M. separata. [ABSTRACT FROM AUTHOR]

Chromosome elimination resulting in haploids is achieved by rapid loss of chromosomes from one parent during the zygote stage and is an important procedure to produce doubled haploid (DH) lines in plants. During crosses between an emasculated wheat (Triticum aestivum L.) and maize (Zea mays L.) as pollen donors, the complete loss of maize chromosomes results in wheat haploid embryos. Through embryo rescue and chromosome doubling processes, pure lines with stable traits can be quickly obtained. The technique is called the "Wheat × Maize System". Although this technology is not new, it remains a practical approach to date. In order to optimize and improve this technology and to achieve its maximum potential in the winter wheat area of China, this paper reviews the previous and ongoing research and technical procedures for the production of wheat DH lines via the maize pollen induction and presents outlooks on DH research and its application in wheat breeding. [ABSTRACT FROM AUTHOR]

Drought is a most prevalent environmental stress affecting the productivity of rainfed wheat and maize in the semiarid Loess Plateau of China. Sustainable agricultural practices such as intercropping are important for enhancing crop performance in terms of better physiological and biochemical characteristics under drought conditions. Enzymatic and non-enzymatic antioxidant enzyme activities are associated with improved abiotic tolerance in crop plants, however, its molecular mechanism remains obscure. A 2-year field study was conducted to evaluate the influence of intercropping treatment viz. wheat mono-crop (WMC), maize mono-crop (MMC), intercropping maize (IM) and wheat (IW) crops, and nitrogen (N) application rates viz. control and full-dose of N (basal application at 150 and 235 kg ha−1 for wheat and maize, respectively) on chlorophyll fluorescence, gas exchange traits, lipid peroxidation, antioxidative properties and expression patterns of six tolerance genes in both crops under rainfed conditions. As compared with their respective monocropping treatments, IW and IM increased the Fo/Fm by 18.35 and 14.33%, PS-11 efficiency by 7.90 and 13.44%, photosynthesis by 14.31 and 23.97%, C-capacity by 32.05 and 12.92%, and stomatal conductance by 41.40 and 89.95% under without- and with-N application, respectively. The reductions in instantaneous- and intrinsic-water use efficiency and MDA content in the range of 8.76–26.30% were recorded for IW and IM treatments compared with WMC and MMC, respectively. Compared with the WMC and MMC, IW and IM also triggered better antioxidant activities under both N rates. Moreover, we also noted that intercropping and N addition regulated the transcript levels of six genes encoding non-enzymatic antioxidants cycle enzymes. The better performance of intercropping treatments i.e., IW and IM were also associated with improved osmolytes accumulation under rainfed conditions. As compared with control, N addition significantly improved the chlorophyll fluorescence, gas exchange traits, lipid peroxidation, and antioxidant enzyme activities under all intercropping treatments. Our results increase our understanding of the physiological, biochemical, and molecular mechanisms of intercropping-induced water stress tolerance in wheat and maize crops. [ABSTRACT FROM AUTHOR]

Waterlogging disasters severely restrict crop production. The middle and lower Yangtze River region (MLYRR) is an important grain-producing region in China but suffers from severe waterlogging disasters. In this study, an agriculture-specific index called the accumulative humidity index was introduced to analyze the spatiotemporal characteristics of waterlogging during different wheat and maize growth stages in the MLYRR from 1960 to 2020. Additionally, the relationships between waterlogging intensities and crop yield fluctuations were revealed. The results showed that over the past 60 years, the intensity of wheat and maize waterlogging in the central and eastern MLYRR have increased; crop waterlogging was more intense in the 1990s–2010s than during the 1960s–1980s, and waterlogging intensity peaked in the 1990s. For both crops, waterlogging was more intense during the early growth stages, but its yield-reducing impacts were more significant during middle and late growth stages. The southern MLYRR (especially southern Anhui) was the region where both crops were most prone to waterlogging, but yields in this region were not severely affected by waterlogging. Compared with wheat, maize was more prone to waterlogging, and its yield was more significantly reduced by waterlogging. In conclusion, this study provides guidance for agricultural waterlogging risk reduction in the MLYRR. [ABSTRACT FROM AUTHOR]

Crop-specific, high-resolution phosphorus rate information is essential for sustainable agricultural fertilizer management in China. However, substantial uncertainties exist in the current phosphorus fertilizer dataset because of only coarse national statistics used in dataset development and no crop-specific information provided. This study harmonized provincial and county-level phosphorus and component fertilizer statistics and crop distribution data to generate 1 km gridded maps of phosphorus rate for rice, wheat and maize in the years of 2004–2016 (CN-P). CN-P provides a comparable estimate on phosphorus rate for each crop over 2004–2016, and demonstrates an improved spatial heterogeneity. Existing dataset developed using national statistics tends to smooth out the variability within country and significantly underestimates actual phosphorus rate. CN-P shows that, during 2004–2016, wheat received the most phosphorus rate (8.7 g P2O5 m−2), while maize showed the rapidest increasing trend (2.36% yr−1). The CN-P dataset has the potential to be widely applied in modeling studies on sustainable agricultural fertilizer management strategies and phosphorus pollution. [ABSTRACT FROM AUTHOR]

Soil degradation and high environmental costs impede agricultural production in North China. A 6-year field experiment was conducted to determine the effects of tillage practice and nitrogen application rate on changes in soil fertility and wheat yield. Four tillage systems (rotary tillage without maize straw return through 6 years, RT; rotary tillage with maize straw return through 6 years, RS; deep tillage with maize straw return through 6 years, DS; and rotary tillage through 2 years followed by deep tillage next year with maize straw applied for two cycles, RS/DS) and three N levels (HN, 300 kg N ha−1, refers to traditional farming practice; MN, 0.75 × HN, 225 kg N ha−1, to recommended N rate; and LN, 0.5 × HN, 150 kg N ha−1, to reduced N rate) were tested. The soil organic carbon, labile organic carbon, inorganic N, available phosphorus, and available potassium under straw return treatments were significantly higher than RT in the 0–30 cm soil layer (p < 0.05). The microbial diversity, invertase, urease, and alkaline phosphatase activities also increased when maize straw was returned. Tillage practices could distribute maize straw in different depths of the soil and then affect soil nutrients, enzyme activity, and microbial diversity. The RS treatment presented the greatest effects in the 0–10 cm layer, while more significant impacts were observed in DS and RS/DS treatments at the 10–30 cm depths. The levels of soil nutrients and enzyme activity increased with an increased N rate. Compared to that under LN, wheat yields increased under HN and MN treatments, whereas there were no significant differences between HN and MN (p > 0.05). An increasing tendency of grain yield was observed in DS and RS/DS, while conversely so in RS. RS/DS had lower farm costs than DS during the study duration. Thus, RS/DS at 225 kg N ha−1 is the best method for improving soil fertility and wheat yield. [ABSTRACT FROM AUTHOR]

Increasing urbanization and affluence have led to changes in food consumption patterns. The application of nitrogen (N) fertilizers ensures food security but also leads to environmental pollution due to N losses, through processes such as acidification, eutrophication, and greenhouse gas emissions. To clarify whether changes in food consumption patterns could increase N losses and to explore sustainable food system pathways, this study integrated the Chinese Food System Dashboard and the Nutrient Flows in Food Chains, Environment and Resources Use model to quantify and compare the link between food consumption and N losses in different agricultural regions using a case study of Bayannur City in the Yellow River Basin from 2000 to 2016. During the study period, Bayannur's food consumption pattern changed from a "high carbohydrate and pork pattern" to a "high fiber and herbivore pattern", which represents a shift from low to high N consumption. The per-capita food consumption decreased by 11.55% from 425.41 kg cap−1, whereas the per-capita N losses increased by 12.42% from 35.60 kg N cap−1. The average share of the plant-oriented and animal-oriented food supply in these losses was 53.39% and 46.61%, respectively. There were differences in the food consumption patterns and N losses in Bayannur's farming, farming–pastoral, and pastoral regions. The changes in N losses were most significant in the pastoral region. The N losses to the environment increased sharply by 112.33% from 22.75 g N cap−1 over the past 16 years. The low level of economic development in Bayannur resulted in a shift in the food consumption pattern to a high N consumption. Four measures to protect food security and reduce the food N cost were proposed: (1) increasing the wheat planting area and maintaining the existing corn one; (2) expanding the scale of high-quality alfalfa planting; (3) enhancing the area of oat grass and wheat replanting; and (4) using modern planting technology. [ABSTRACT FROM AUTHOR]

Soil moisture (SM) is a key variable of the regional hydrological cycle and has important applications for water resource and agricultural drought management. Various global soil moisture products have been mostly retrieved from microwave remote sensing data. However, currently there is rarely spatially explicit and time-continuous soil moisture information with a high resolution at the national scale. In this study, we generated a 1 km soil moisture dataset for dryland wheat and maize in China (ChinaCropSM1 km) over 1993–2018 through a random forest (RF) algorithm based on numerous in situ daily observations of soil moisture. We independently used in situ observations (181 327 samples) from the agricultural meteorological stations (AMSs) across China for training (164 202 samples) and others for testing (17 125 samples). An irrigation module was first developed according to crop type (i.e., wheat, maize), soil depth (0–10, 10–20 cm) and phenology. We produced four daily datasets separately by crop type and soil depth, and their accuracies were all satisfactory (wheat r 0.93, ubRMSE 0.033 m 3 m -3 ; maize r 0.93, ubRMSE 0.035 m 3 m -3). The spatiotemporal resolutions and accuracy of ChinaCropSM1 km were significantly better than those of global soil moisture products (e.g., r increased by 116 %, ubRMSE decreased by 64 %), including the global remote-sensing-based surface soil moisture dataset (RSSSM) and the European Space Agency (ESA) Climate Change Initiative (CCI) SM. The approach developed in our study could be applied to other regions and crops in the world, and our improved datasets are very valuable for many studies and field management, such as agricultural drought monitoring and crop yield forecasting. The data are published in Zenodo at https://doi.org/10.5281/zenodo.6834530 (wheat 0–10) (Cheng et al., 2022a), https://doi.org/10.5281/zenodo.6822591 (wheat 10–20) (Cheng et al., 2022b), https://doi/org/10.5281/zenodo.6822581 (maize 0–10) (Cheng et al., 2022c) and https://doi.org/10.5281/zenodo.6820166 (maize 10–20) (Cheng et al., 2022d). [ABSTRACT FROM AUTHOR]

Spring wheat–summer maize (SWSM) annual crop systems were formed to satisfy the maize grain mechanized harvest thermal requirement in the thermal–resource–limited region of the North China Plain. However, the nitrogen (N) application rate effect on SWSM annual yield formation, N accumulation and utilization were barely evaluated. Two–year field experiments were conducted to evaluate the effects of the N application rate on the annual yield of SWSM, observe N accumulation and utilization, and identify the optimized N application. The experiments were conducted under 5 N levels of 0 (N0), 180 (N180), 240 (N240), 300 (N300), and 360 (N360) kg ha−1. The results showed that spring wheat, summer maize and annual cereal yield under the N240 and N480 treatments obtained the highest grain yield (GY) of 5038, 1282 and 16,320 kg ha−1, respectively, and the optimal N application rate was estimated using a linear–plateau model to be 231–307, 222–337 and 463–571 kg ha−1 with maximum GY of 4654–5317, 11,727–12,003 and 16,349–16,658 kg ha−1, respectively. With the increase in the N application rate, the dry matter accumulation (DM) were significantly increased by 16.9–173.5% for spring wheat and 11.1≈–76.8% for summer maize, respectively; and the annual cereal DM was 15.1–179.7% greater than that with N0 treatment, respectively. Spring wheat, summer maize and the annual cereal total N accumulation (TN) under N360 and N720 treatments were significantly increased by 5.4–19.1%, 16.6–32.3% and 11.5–26.2%, respectively, compared to the other treatments; however, N use efficiency for biomass and grain production (NUEbms and NUEg) were decreased significantly by 10.9–13.6% and 8.9–20.7%, 6.8–13.8% and 12.2–15.6%, and 5.5–11.7% and 10.0–16.0%, respectively. Meanwhile, the N partial factor productivity (PFPN), N agronomy use efficiency (ANUE), N recovery efficiency (NRE) and N uptake efficiency (NEupk) under the N240 treatment for spring wheat and summer maize obtained high levels of 20.99 and 47.01 kg−1, 9.27 and 16.35 kg−1, 32.53% and 32.44%, and 0.85 and 0.72 kg−1, respectively. Correlation analysis showed that the N application rate, TN and NEupk played significantly positive roles on GY, spring wheat spilke grain number, summer maize ear grain number and 1000–grain weight, DM LAImax and SPADmax, while NUEbms, NUEg, PFPN and ANUE always played negative effects. These results demonstrate that spring wheat, summer maize and annual cereal obtained the highest GY being 4654–5317, 11,727–12,003 and 16,349–16,658 kg ha−1 with the optimal N application rate 231–307, 222–337 and 463–571 kg ha−1, respectively, which provide N application guidance to farmer for spring wheat–summer maize crop systems to achieve annual mechanical harvesting in the thermal–resource–limited region of the North China Plain. [ABSTRACT FROM AUTHOR]

Because of the effect of nitrogen (N) fertilization on soil-derived N uptake, N difference (FNRDiff) and 15 N tracer (FNR15N) methods may give significantly different estimates of the fertilizer N recovery (FNR) in crops. To better understand quantitative differences in FNR (∆FNR) between the two methods, we evaluated the effect of fertilizer N input rates on ∆FNR and soil-derived N uptake by considering data from field 15 N tracer experiments of cereal crops across China, including N-unfertilized treatments. The FNRDiff was significantly higher than the corresponding FNR15N in wheat (38% vs. 36%), maize (38% vs. 31%), and rice (40% vs. 31%) under fertilizer applications of 40–500 kg N ha−1. Except in wheat at 250–500 kg N ha−1, FNRDiff was higher than FNR15N at various N input rates in the three crops, and ∆FNR decreased with increasing rates of applied N. The ∆FNR apparently occurred because added-N interaction (ANI) increased soil-derived N uptake (by 5% for wheat, 11% for maize, and 24% for rice). For wheat in particular, ANI values decreased significantly as N input rates increased, with a switch from positive to negative above 252 kg N ha−1. This result suggests that the decrease in soil-derived N uptake is mainly caused by the negative rhizosphere N priming and the law of diminishing returns (current-season non-fertilizer N input or previous-season residual fertilizer N) under high N input, but not by the N pool substitution. Finally, we propose a new method for accurately distinguishing direct and indirect pathway contributions to ∆FNR. This study helps to improve understanding of the underlying mechanisms of discrepancies between the N difference method and the 15 N tracer method for estimating the fertilizer N recovery in crops. [ABSTRACT FROM AUTHOR]

Straw mulching farming is currently an effective dry farming technique for improving arid soil environments. Straw mulching technology can increase the infiltration capacity of soil water and improve crop yield and water use efficiency. In this study, the aim is to improve the soil water holding capacity, water retaining capacity, and comprehensive water use efficiency of crops in dry farmland. First, the response surface model is used to study and analyse the optimal parameters of straw returning and its mulching technology, and then, the crop yield, water consumption, and comprehensive water use efficiency of spring corn under different mulching conditions during 2017-2019 are studied. The test results show that the optimized parameters obtained by the response surface model are as follows: film thickness is 0.03 mm, straw returning amount is 4500 kg/hm2, straw particle size is 5 mm, and straw returning depth is 25 mm. At this time, the maximum soil water storage can reach 404.50 mm. The results of the straw mulching test show that under 4500 kg/hm2 mulching, the soil has more water storage, higher soil water content, and a simultaneous increase in water consumption, which is conducive to the efficient use of limited precipitation by crops. The field experiment for three years shows that 4500 kg/hm2 straw (wheat) mulching in the dry farming area of southern Ningxia can better store water and protect soil moisture, promote the virtuous cycle of farmland soil water, and show outstanding performance in improving corn yield and water use efficiency, which can be popularized and implemented in spring corn production in this area. [ABSTRACT FROM AUTHOR]

Rice seedling blight is a globally occurring seedling disease caused by multiple pathogens. It is currently the most common disease affecting rice production in northeast China; hence, determining the causal agents, including its biological characteristics, host range, and fungicide efficacy is vital for its effective management. The present study obtained 45 pathogenic isolates from diseased rice seedlings in Suihua, Heilongjiang Province, China. Of these, five pathogens were identified based on their morphology and molecular identification, while 10 oomycete isolates were identified as Pythium aristosporum—the first to be reported in rice seedling blight. Its optimum growth conditions include a temperature of 25 °C, pH 6, and photoperiod of 24 h. Except for soybean (Glycine max (L.) Merr.), black soybean (Glycine max var.), and cucumber (Cucumis sativus L.), P. aristosporum can potentially infect and cause seedling blight on other hosts, such as wheat (Triticum aestivum L.), maize (Zea mays L.), sorghum (Sorghum bicolor (L.) Moench), alfalfa (Medicago sativa L.), oats (Avena sativa L.), and white clover (Trifolium repens L.). Its isolates were found to be highly sensitive to metalaxyl + propamocarb (EC50 = 0.0138 μg/mL) with 84.1% efficacy at 313 μg/mL. These results can serve as the basis for controlling P. aristosporum. [ABSTRACT FROM AUTHOR]

Field cultivation practices have changing the carbon and nitrogen cycles in farmland ecosystem, soil organic carbon (SOC) and total nitrogen (TN) were the important pa- rameters in maintaining soil quality and increasing agricultural productivity, however, N application's effects on the SOC and TN storage capacity under intensive wheat- maize cropping system remain unclear. Therefore, we investigated the characteristics and relationships of SOC and TN for wheat-maize cropping system under nitrogen treatments. In doing so, continuous applications of four nitrogen application rates were examined: 0, 180, 240 and 300 kg ha-1 (N0, N180, N240 and N300, respectively). Wheat yields under N180 and N240 were significantly higher than that under N300, while the maize yields under N180, N240 and N300 were significantly higher than that under N0 by 79.79, 85.23 and 86.85%, respectively; the TN content and storage were significantly higher under N240 than that under other N levels in 40-60 cm soil layer after wheat growing season; the SOC content and storage under N180 and N240 were significant higher than that under N300 in 20-40 cm after maize growing season. The correlations between SOC and TN contents (or storage) were stronger after wheat planting than maize planting. These findings provide a basis for further studies on the effect of long-term N application on SOC and TN storage, crop quality and nitrogen use efficiency under wheat-maize cropping systems. [ABSTRACT FROM AUTHOR]

To determine the effects of air pollution on crop yields, weather, air pollution, and maize and winter wheat yield data from 331 cities in China from 2014 to 2016 were collected and analysed. Furthermore, support vector regression and the crop growth model were applied to extrapolate the air pollution data of Beijing and Hetian and verify the relationship between air pollution and yield. Precisely, heavy air pollution usually occurred in North China, but less than moderate air pollution levels affected crop yields statistically insignificantly. Moreover, both the winter wheat and maize yields increased in moderate air pollution periods but decreased in heavy air pollution periods in 2014, 2015 and 2016. Importantly, a threshold value was necessary for the heavy air pollution periods to trigger a yield decrease. The threshold values of maize in 2015 and 2016 were 7 days and 5 days, respectively, while that of winter wheat was 10 days in both 2015 and 2016. Once the heavy air pollution periods exceeded the threshold value, both the winter wheat and maize yields decreased linearly with the periods. PM2.5 was the main air pollutant in Beijing in 2014, while PM2.5 and PM10 were the main air pollutants in Hetian in both 2015 and 2016. Regardless of whether the main air pollutant was PM2.5 or PM10, the simulated potential winter wheat yields by the crop growth model with moderate air pollution for the whole growth period were all higher than the yields under observed and heavy air pollution conditions. [ABSTRACT FROM AUTHOR]

Agricultural system models provide an effective tool for forecasting crop productivity and nutrient budgets under future climate change. This study investigates the potential impacts of climate change on crop failure, grain yield and soil organic carbon (SOC) for both winter wheat (Triticum aestivum L.) and maize (Zea mays L.) in northern China, using the SPACSYS model. The model was calibrated and validated with datasets from 20-year long-term experiments (1985–2004) for the Loess plateau, and then used to forecast production (2020–2049) under six sharing social-economic pathway climate scenarios for both wheat and maize crops with irrigation. Results suggested that warmer climatic scenarios might be favourable for reducing the crop failure rate and increasing the grain yield for winter wheat, while the same climatic scenarios were unfavourable for maize production in the region. Furthermore, future SOC stocks in the topsoil layer (0–30 cm) could increase but in the subsoil layer (30–100 cm) could decrease, regardless of the chosen crop. [ABSTRACT FROM AUTHOR]

China has a huge resource potential for biomass‐based renewable energy development, but the resources of field residues are still not effectively used. Rice, maize, and wheat made up 89% of staple crop production in China in 2009. A comprehensive assessment of field residues of these three crops is necessary for the development of biomass‐based industries. This research was based on multiyear county‐level data of crop production, area and yield, as well as the crop phenology information from agrometeorological stations. Spatial and temporal analyses were conducted to quantify the spatial patterns, seasonal variations, and temporal trends of the three major field residues. The mean amount of field residue of rice, maize, and wheat was 470.8 Mt/year from 2002 to 2009. Rice residue topped the field residues at 188.5 Mt/year, followed by maize (152.6 Mt/year) and wheat (129.8 Mt/year). The resource supply of field residues varied temporally throughout the season, where peak months are May, June, September, and October. The resources of all three field residues increased from 2002 to 2009, topped by maize residues at a rate of 10.0 Mt/year. Spatially, high production counties had the fast growth rate and a strong positive spatial autocorrelation. The results showed that the intersection area of East and South Central regions has a spatially concentrated residue density and a stable supply for 5 months. The region can be considered as a suitable region for bioenergy development. A better understanding of spatial and temporal distribution of crop residues could facilitate strategic and tactical bioenergy planning. [ABSTRACT FROM AUTHOR]

Northwest China is characterized by a high water deficit and regular water resource shortages. These issues have become limiting factors for agricultural and socioeconomic development. Based on a trend-preserving method of bias correction, we calibrated the maximum temperature and minimum temperature in four CMIP5 GCMs (CNRM, IPSL, BCC, and CMCC). Then, we investigated variations in the regional crop water requirement (CWR) in the total growth stages for five main crops (cotton, spring corn, summer corn, spring wheat, and winter wheat) in the past (1961–2005) and future (2006–2100). The results suggest that the MK test yielded insignificant decreasing CWR trends in the total growth stages of cotton (0.10 mm/year), spring corn (0.13 mm/year), and spring wheat (0.05 mm/year) and insignificant increasing trends for summer corn (0.02 mm/year) and winter wheat (0.32 mm/year) historically. In the future period, for the same type of crops (cotton), the CWRs in all scenarios (RCP 2.6, 4.5, and 8.5 scenarios) for all GCMs exhibited significant positive trends; for the same GCM (BCC), the CWRs projected for five major crops in the RCP 4.5 and 8.5 scenarios all exhibited extremely significant MK trends (99%); in addition, the CWRs' rate increases of the five crops projected in RCP8.5 scenario by BCC exhibited the following order: winter wheat (1.25 mm/year), summer corn (1.15 mm/year), spring corn (1.02 mm/year), cotton (0.97 mm/year), and spring wheat (0.87 mm/year). The maximum CWRs of winter wheat were mainly observed in southeastern Northwest China, while those of the other four crops occurred in southern Xinjiang. [ABSTRACT FROM AUTHOR]

Managing reactive nitrogen (Nr) in agricultural production is crucial for addressing the triple challenges of food security, climate change and environmental degradation. Intensive work has been conducted to investigate the effects of mitigation strategies on reducing Nr losses by ammonia emission (Nr-NH 3), nitrous oxide emission (Nr-N 2 O) and nitrate leaching (Nr-NO 3 -) separately. This meta-analysis evaluated the efficiency of each strategy in mitigating Nr losses coupled with grain yield responses. The results indicate that producing one Megagram (Mg) of wheat grains caused higher Nr losses, twice that of rice and 17% that of maize. The Nr-NH 3 and Nr-NO 3 - were the dominant sources of Nr losses of the three crops (96%), while Nr-NH 3 only presented 86% of the total Nr losses for rice. Reducing the N rate strategy decreased the yield by 33% and the Nr losses by 62% compared with the conventional rate (150–250 kg N ha−1) as an average of the three crops. In contrast, increasing the N rate higher than 250 kg N ha−1 amplified the yield by 15% but also caused a 71% increase in Nr losses compared with the conventional rate. Although subsurface application decreased Nr losses by 5%, this study rejected this approach as an effective strategy due to a 4% yield decline on average of the grain crops. Slow-release fertilizers decreased Nr-NH 3 and Nr-N 2 O losses by 41–58% and 54–89%, respectively, of the highest losses under urea in the three crops, but also led to yield reductions. Organic amendments achieved the highest drop in Nr-NO 3 - loss by 66% in maize coupled with yield declines. Biochar increased wheat and maize yields by 0.3 and 0.1 Mg, respectively, coupled with 1 kg reduction in Nr losses. On average, inhibitors augmented the grain yields by 0.2 Mg ha−1 for each 1 kg decline in Nr losses. In conclusion, for sustainable agricultural intensification, biochar (for wheat only) and inhibitors (for the three crops) are strongly recommended as mitigation strategies for Nr losses from grain crop production systems in China. • Changes in grain yields with reactive nitrogen losses in China were assessed. • Wheat reactive nitrogen losses were twice higher than rice and 17% than maize. • Ammonia emission and nitrate leaching were the dominant loss sources by 96%. • Biochar reduced wheat reactive nitrogen losses, while increase grain yield. • Inhibitors reduced losses in the three crops coupled with yield increases. [ABSTRACT FROM AUTHOR]

The current study was to better understand the potential factors affecting aflatoxin B1 (AFB1) accumulation varies between different grains. The nutrient composition and contents of defatted substrates were determined; additionally, according to the nutrient content of the substrates, the effects of starch, soluble sugars, amino acids, and trace elements on AFB1 production and mycelial growth in Czapek-Dox medium were examined. These results verified that removal of lipids from ground substrates significantly reduced the substrate’s potential for AFB1 production by Aspergillus flavus. Maltose, glucose, sucrose, arginine, glutamic acid, aspartic acid, and zinc significantly induced AFB1 production up to 1.7- to 26.6-fold. And stachyose more significantly promoted A. flavus growth than the other nutrients. Thus, this study demonstrated that, combined with the nutrients content of grains, in addition to lipids, sucrose, stachyose, glutamic acid, and zinc might play key roles in various grains that are differentially infected by A. flavus. Particularly, two new nutrients (arginine and stachyose) of the grains we found significantly stimulate AFB1 production and A. flavus growth, respectively. The results provide new concepts for antifungal methods to protect food and animal feed from AFB1 contamination. [ABSTRACT FROM AUTHOR]

Humans are naturally and frequently exposed to a multitude of mycotoxins, but health risk assessments are usually performed on individual mycotoxins, which may underestimate the total risks. In this study, we assessed for the first time the cumulative health risks of concomitant exposure via dietary intake (DI) to multiple mycotoxins, namely deoxynivalenol (DON) and its acetyl derivatives of 3-acetyldeoxynivalenol (3-ADON) and 15-acetyldeoxynivalenol (15-ADON), based on the concentration addition (CA) concept. A cross-sectional study was conducted in seven districts in Shanghai, China with 1269 participants and 330 wheat and maize samples analyzed. After probabilistic analysis using Monte Carlo simulation, the results showed no health risks to the population in Shanghai considering individual mycotoxins. However, if the cumulative health risks were calculated based on the combined consideration of DON with either 3-ADON or 15-ADON or both, the DI values in 95th percentile were up to 1087 ng/kg body weight/day, exceeding the Provisional Maximum Tolerable Daily Intake (PMTDI) of 1000 ng/kg body weight/day and hence representing potential health risks to the population in Shanghai. The integrated study proposed here could be a model strategy for cumulative health risk assessment on the co-occurring hazards in the fields of food safety combined with environmental contaminants. [ABSTRACT FROM AUTHOR]

The increases in crop yield in China are linked to massive increases in fertilizer and water input, which have also accelerated the degradation of soil and environmental pollution. Nevertheless, the long-term changes in crop yield and water use efficiency (WUE) of three major cereals (maize, wheat and rice) in response to field management practices are rarely reported. This meta-analysis evaluated the effect of field management (nitrogen input (N), irrigation, fertilizer type, fertilization frequency, and irrigation method) on crop yield and WUE between 1990 and 2020 based on 3152 observations. We found that the N thresholds for maize, wheat, and rice were 150–200 kg ha−1, 140–210 kg ha−1, and 90–135 kg ha−1, respectively. N fertilization within the threshold levels increased the crop yield and WUE of maize (84% and 74%), wheat (47% and 41%), and rice (55% and 30%). The irrigation (mm) thresholds for maize and wheat were 180–240 mm and 300–400 mm and crop yield and WUE were increased by 37% and 13% for maize and by 84% and 41% for wheat. Agricultural management increased yield and WUE (% and %) through drip irrigation (23 and 13 maize; 31 and 14 wheat), alternate wetting and drying (AWD) (26 and 30 rice), split fertilization (31 and 21 maize; 64 and 40 wheat; 33 and 25 rice) and organic–inorganic fertilizer (43 and 39 maize; 68 and 66 wheat; 38 and 34 rice). With the increase in HI (humidity index) from 10 to 30, the contribution of irrigation to WUE decreased, but that of fertilization increased. This study concludes that N fertilizer and irrigation applications between threshold levels along with suitable field management is a win–win strategy to achieve climate-smart agricultural production with minimum damages to soil and environment and at lower dependence on fertilizer and irrigation. [ABSTRACT FROM AUTHOR]

Various cropping patterns are extensively used on the North China Plain, which greatly alter various soil properties. Although these soil properties respond differently to the different cropping patterns, little is known about the possible effects of cropping patterns on desalinized soils. To assess the effects of the different cropping patterns on soil properties and enzyme activities, a long-term field experiment was conducted at the Nanpi Agro-Ecological Station in Hebei Province, China. The cropping patterns under study were the single-cropping patterns of winter wheat (Triticum aestivum L.), spring maize (Zea mays), and spring cotton (Gossypium hirsutum), and the double-cropping pattern of winter wheat–summer maize (WW–SM), which is the predominant cropping pattern on the North China Plain. Soil samples were collected at a depth of 0–100 cm, depending on the soil properties. Our results indicated that soil available phosphorous (P) and available potassium (K) concentrations at 0–20 cm were greater than those of the subsurfaces. Soil organic matter declined with depth, and WW–SM had the highest amount in the deep levels. The WW–SM cropping pattern also generally showed greater levels of enzyme activities than did the single-cropping patterns, proving that diverse crops can enhance enzyme activities. Soil pH generally increased with depth despite there being no significant differences between the cropping patterns. No significant effects were observed on soil electrical conductivity (EC). However, EC generally increased with depth in spring cotton and winter wheat and declined in spring maize and WW–SM. Winter wheat had a significant aggregate size (<0.053 mm) at 20–40 cm depth and generally showed the lowest amount of nutrients. This study suggests that a fallow period allows the soil to regenerate its structure, whereas WW–SM enhances high soil organic matter in the deep soil layers and promotes increased soil enzyme activities. This indicates that crop rotation could sustainably exploit soil resources without reducing fertility over a long period. There is a need to incorporate different soil management practices for single-cropping patterns to increase their productivity, especially in spring maize, whose organic matter declined the most. Our results also show a need to diversify to different crop rotations to utilize their benefits and enhance soil productivity while increasing crop output. [ABSTRACT FROM AUTHOR]

Image analysis of the Yellow River beach area since 1987 provided land use and water body patterns to support effective agricultural and environmental management. Landsat and Sentinel-2A/B images, and data from the Third National Land Survey, were used to examine the water body and land use patterns. The continuous beach land since 1987 was calculated from annual vegetation and water body indexes while that of cultivated land was extracted from the Third National Land Survey. Object-Oriented Feature Extraction was used to extract staple crops. The results showed that 58.26% of the beach area was cultivated land. Continuous beach land covered an area of 1630.98 km2 and was consisted of scattered patches that were unevenly distributed between the north and south banks of the Yellow River. The staple crop types in the beach area, winter wheat and summer corn accounted for 72.37% and 68.03% of the total cultivated land. Affected by the strategy on the Yellow River basin in China, as the ecological space and protection continue to increase, this study provides basic scientific references for the correct use of cultivated land resources and protection of the balance of soil and water resources dynamic utilization and balance of cultivated land protection and ecological protection. [ABSTRACT FROM AUTHOR]

• A water-energy-food relative index for cropping systems at the field scale is proposed. • Synergy among water, energy and food in the North China Plain is evaluated. • Sustainable systems can balance crop production while reducing resource depletion. Extreme climate change, rapid population growth and economic development drive a growing demand for resources, which lead to energy, food, water and their intertwined nexus becoming increasingly important. Agricultural decisions considering the interconnections among water, energy, and food are critical. The consumption of large amounts groundwater and non-renewable energy by the predominant traditional wheat-maize cropping system has caused a serious water shortage in the North China Plain (NCP), which is a large food production region in China. This situation has strained the relationship between water/energy consumption and food production. It is important to seek synergy in the water-energy-food nexus. This paper proposed a relative index of water-energy-food (WEF RI) based on different values of resource consumption and use efficiency between treatment systems and control system to analyze the synergy between water utilization, energy consumption and food supply in different cropping systems at the field scale. The goal is to seek a sustainable cropping system to balance crop production while reducing energy consumption and water depletion. In this case, different systems including monocropped maize (Zea mays) (MM), intercropped maize and soybean (Glycine max) (MS), relay cropped of maize with pea (Pisum sativum) (MP) and potato (Solanum tuberosum) (MO), rotation of maize with spinach (Spinacia oleracea) (MI) and ryegrass (Secale cereale) (MR), and using traditional wheat-maize (Triticum aestivum) (MW) as a control. MM, MS, MP and MO were the best systems within a particular range of food supply reduction. The WEF RI of the MM/MS system was the highest (2.96/2.78). Compared to the MW system, the groundwater consumption of MM/MS was reduced by 73.84%/73.84%, and non-renewable energy inputs were reduced by 48.01%/48.30%; however, the food supply decreased by 48.05%/51.70%. The WEF RI of the MP system was 1.98. In comparison with the MW system, the groundwater consumption of the MP system was reduced by 28.46%, and the non-renewable energy inputs were reduced by 42.68%. However, the food supply decreased by 37.13%. The WEF RI of MO system was 1.92. Compared to the MW system, the groundwater consumption of MO was reduced by 11.47%, non-renewable energy inputs were reduced by 32.14%, and the food supply only decreased by 26.27%. In conclusion, we theoretically proposed the following references for cropping systems in the NCP: MM and MS are implemented when the areas has extreme water shortages, MO is implemented when a less than 30% reduction in the food supply capacity is acceptable, and MP is recommended if a 30%–40% reduction in the food supply is acceptable. [ABSTRACT FROM AUTHOR]

The cadmium (Cd) activity in soil has been widely studied. However, the interactive effects of soil properties (e.g. soil pH, CEC, and SOM) on Cd transfer from soil to grain are generally overlooked. In total 325 datasets including soil pH, CEC, SOM, and soil Cd content were used in this study. The descriptive statistics indicated that Cd content in wheat and maize soils ranged from 0.05 to 10.31 mg/kg and 0.02–13.68 mg/kg, with mean values of 0.87 and 1.14 mg/kg, respectively. Cd contents in wheat and maize grains were 0.01–1.36 mg/kg and 0.001–1.08 mg/kg with average values of 0.15 and 0.10 mg/kg, respectively. The results of SEM demonstrated that the interactive effects of soil properties contributed more to Cd transfer from soil to wheat grain than the soil Cd content. Subsequently, CITs-MLR indicated that the critical factors, including soil pH and total soil Cd content, could mask the contribution of other soil properties on Cd accumulation in grain; soil CEC may prevent Cd from leaching and therefore improve grain Cd level of wheat especially at acidic soil condition. The result of derived Cd thresholds revealed that current Cd thresholds are not completely suitable to wheat and maize grain at different soil conditions. This study provides a new model for further investigation on relationships between soil properties, soil Cd content and grain Cd level. Image 1 • The interactions of soil properties influence Cd transfer in a higher degree than soil Cd content. • Soil pH may mask other soil properties' contribution on Cd transfer. • Diverse Cd thresholds for different soil conditions are obtained. [ABSTRACT FROM AUTHOR]

Deoxynivalenol (DON), along with 3-acetyl-deoxynivalenol (3-ADON) and 15-acetyl-deoxynivalenol (15-ADON), occur in grains and cereal products and is often hazardous to humans and livestock. In this study, 579 wheat samples and 606 maize samples intended for consumption were collected from China in 2017 and analyzed to determine the co-occurrence of type-B trichothecenes (DON, 3-ADON, and 15-ADON). All the wheat samples tested positive for DON, while 99.83% of the maize samples were DON-positive with mean DON concentrations of 165.87 and 175.30 μg/kg, respectively. Per the Chinese standard limits for DON, 3.63% of wheat and 2.97% of the maize samples were above the maximum limit of 1000 μg/kg. The DON derivatives (3-ADON and 15-ADON) were less frequently found and were present at lower levels than DON in wheat. 3-ADON and 15-ADON had incidences of 13.53% and 76.40%, respectively, in maize. By analyzing the distribution ratio of DON and its derivatives in wheat and maize, DON (95.51%) was the predominant toxin detected in wheat samples, followed by 3.97% for the combination of DON + 3-ADON, while DON + 3-ADON + 15-ADON and DON + 15-ADON were only found in 0.17% and 0.35% of wheat samples, respectively. Additionally, a large amount of the maize samples were contaminated with DON + 15-ADON (64.19%) and DON (22.11%). The samples with a combination of DON + 3-ADON and DON + 3-ADON + 15-ADON accounted for 1.32% and 12.21%, respectively. Only one maize sample did not contain all three mycotoxins. Our study shows the necessity of raising awareness of the co-occurrence of mycotoxin contamination in grains from China to protect consumers from the risk of exposure to DON and its derivatives. [ABSTRACT FROM AUTHOR]

The production of cereals, including rice, wheat, and maize has increased in China over the past 20 years. However, variations in the production and cultivated area of cereals remains unclear. In this study, we collected and analyzed the cereal production and cultivated area in China from 1998 to 2016. An 85% increase in cereal production was recorded from 1998 to 2016, due to an increase in the maize production along with the increase in the cultivated area. Meanwhile, rice and wheat production have been stable since 2000. No change occurred in the rice cultivated area through 2016, and a 19% decrease in the wheat cultivated area was observed in 2016 relative to 1998. In addition, a significant positive relationship was observed among cereal production, maize production, and cultivated area (p < 0.0001). Together, the increase in cereal production in China over the past two decades has resulted from the increase in maize cultivated area and the consequent increase in maize production. [ABSTRACT FROM AUTHOR]