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Intensive vegetable production in greenhouses has rapidly expanded in China since the 1990s and increased to 1.3 million ha of farmland by 2016, which is the highest in the world. We conducted an 11‐year greenhouse vegetable production experiment from 2002 to 2013 to observe soil organic carbon (SOC) dynamics under three management systems, i.e., conventional (CON), integrated (ING), and intensive organic (ORG) farming. Soil samples (0–20 and 20–40 cm depth) were collected in 2002 and 2013 and separated into four particle‐size fractions, i.e., coarse sand (> 250 µm), fine sand (250–53 µm), silt (53–2 µm), and clay (< 2 µm). The SOC contents and δ13C values of the whole soil and the four particle‐size fractions were analyzed. After 11 years of vegetable farming, ORG and ING significantly increased SOC stocks (0–20 cm) by 4008 ± 36.6 and 2880 ± 365 kg C ha−1 y−1, respectively, 8.1‐ and 5.8‐times that of CON (494 ± 42.6 kg C ha−1 y−1). The SOC stock increase in ORG at 20–40 cm depth was 245 ± 66.4 kg C ha−1 y−1, significantly higher than in ING (66 ± 13.4 kg C ha−1 y−1) and CON (109 ± 44.8 kg C ha−1 y−1). Analyses of 13C revealed a significant increase in newly produced SOC in both soil layers in ORG. However, the carbon conversion efficiency (CE: increased organic carbon in soil divided by organic carbon input) was lower in ORG (14.4%–21.7%) than in ING (18.2%–27.4%). Among the four particle‐sizes in the 0–20 cm layer, the silt fraction exhibited the largest proportion of increase in SOC content (57.8% and 55.4% of the SOC increase in ORG and ING, respectively). A similar trend was detected in the 20–40 cm soil layer. Over all, intensive organic (ORG) vegetable production increases soil organic carbon but with a lower carbon conversion efficiency than integrated (ING) management. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract An increasing disconnect between livestock production and croplands has been observed in many world regions, including China, which has the world's largest livestock production sector. Here we propose a cropland-based livestock production system to rebuild the linkage between livestock and cropland from both agriculture production and human consumption perspectives for China. In 2015, the total excretion nitrogen (N) generated by livestock production operations was 14.6 Tg N, and it would grow to 15.0 Tg in 2030 by extrapolating current trends. The optimal demand of total N by crops in China was estimated to be 23.0 Tg N in 2030, suggesting that Chinese livestock would be within the carrying capacity of cropland on national level, but substantial variations were found across provinces. The carrying capacity of cropland with regard to N input from manure would be exceeded in 74% provinces, under the assumption that manure providing half of the N supply for crops. Furthermore, from the perspective of domestic feed supply for livestock production, about 51% of feed N needs to be imported. If following the optimized dietary structure of China to manage livestock sector, livestock production could be reduced by 37% in excretion nitrogen, which would not only benefit the food security and human health, but also mitigate the agricultural pollution. Accordingly, policy regulations on reduction and spatially reallocation of livestock production on a regional scale could substantially reduce manure N loss from 10.5 Tg yr−1 to 1–1.2 Tg yr−1 under different recoupled scenarios. [ABSTRACT FROM AUTHOR]

• Effects of cross ridge tillage were assessed from long-term and multi-site measurements. • Cross ridge reduced runoff, sediment and N and P loss from sloping farmland. • N and P losses decreased greatly with the decrease of runoff in sloping farmlands. • Crop cover is effective in reducing N and P loss in sloping farmland in YN and CQ. Losses of nutrients, water and soil from sloping farmlands have a large potential to contribute to water eutrophication and land degradation. However, few long-term and multi-site measurements are available to assess the magnitude of effects of cross-ridge tillage on surface runoff and nitrogen (N) and phosphorus (P) losses from sloping farmlands. Field experiments were conducted under natural rainfall conditions for six to seven years across four experimental sites in southern China. Each site-year experiment consisted of three management practices: downslope ridge without fertilizer as control (CK), downslope tillage with fertilizer (DF), and cross-ridge with fertilizer (CF). Results indicated that compared to the downslope tillage practice, cross-ridge tillage reduced the average annual runoff by 6.11% to 64.2%. Compared with DF, CF significantly decreased total N (TN) and total P (TP) losses by 11.3% to 69.7% and 15.9%- to 63.5%, respectively (P < 0.05). The decreases in TN and TP losses were significantly associated with sediment yield reduced by cross-ridge, which significantly reduced both particulate N and particulate P losses. While TN loss in CF was dominated by total dissolved N (62.4%), particulate P accounted for 68.4% of TP in runoff. Across all tillage practices, N and P losses increased at higher soil N and P contents, indicating the necessity of adopting crop and nutrient management practices to reduce soil nutrient levels and thus nutrient losses from sloping farmlands. Despite regional and temporal variabilities, cross-ridge tillage consistently reduced surface runoff, sediment yield, and N and P losses compared with downslope tillage. In conclusion, cross-ridge tillage is an effective conservation measure to reduce soil erosion and nutrient losses from sloping farmland in China's hilly regions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Optimal LS-factor formulas selected for soil erosion calculation using RUSLE. • Optimal L-factor and S-factor formulas calculate soil erosion with 5.55% RE. • RUSLE-Cal model constructed to auto-calculate soil erosion using five methods. • A suitability selection table of LS-factor provided to improve accuracy of RUSLE. The slope length and slope steepness factor (LS-factor) formula in the Revised Universal Soil Loss Equation (RUSLE) has a considerable level of uncertainty due to the existence of multiple methods. In this study, four commonly used formulas for the slope length factor and two formulas for the slope gradient factor were chosen and combined based on their applicability to the specific research context. Based on the ModelBuilder in ArcGIS Pro 3.0, a RUSLE calculation model (RUSLE-Cal model) was constructed in the study, which can automatically calculate the soil erosion modulus using four commonly used RUSLE formulas and one combination formula. Taking the Fengyu River watershed in China as a case study, this research analyzes the uncertainty of different LS-factor formulas and validates the accuracy of RUSLE simulation results using measured sediment data. The optimal combination of LS-factor formulas is selected, and an in-depth analysis is conducted on the origins and suitability of each formula. The accuracy validation results indicate that, for the Fengyu River watershed, the optimal combination of L-factor and S-factor formulas were determined based on the slope gradient. Specifically, L1 formula was used when slope ≤ 10°, and L3 formula was used when slope greater than 10°. Similarly, S1 formula was used when slope ≤ 18°, and S2 formula was used when slope greater than 18°. The RUSLE model achieved the best simulation results with a relative error of 5.55%. The results of the uncertainty analysis indicate that the four formulas have a significant impact on the simulated soil erosion, with a RE ranging from −99.18% to 31.49%. Therefore, based on literature review and formula analysis, a suitability selection table for L-factor and S-factor formulas is provided, which can provide formula basis for the improvement of soil erosion in watershed models. [ABSTRACT FROM AUTHOR]

The curve number (CN) method developed by the United States Department of Agriculture (USDA) in 1954 is the most common adopted method to estimate surface runoff. For years, applicability of the CN method is a conundrum when implementing to other countries. Specifically, countries with more complex natural environment may require more dedicated adjustments. Therefore, the current CN look-up table provided by USDA might not be appropriate and could be questionable to be applied directly to regions elsewhere. Some studies have been conducted to modify CN values according to specified natural characteristics in scattered regions of mainland China. However, an integral and representative work is still not available to address potential concerns in general matters. In this study, a large set of rainfall-runoff monitoring data were collected to adjust CN values in 55 study sites across China. The results showed that the revised CN values are largely different from CN look-up table provided by USDA, which would lead to huge errors in runoff estimation. In this study, the revised CN (dubbed CN-China) provides better reference guidelines that are suitable for most natural conditions in China. In addition, scientists and engineers from other parts of the world can take advantage of the proposed work to enhance the quality of future programs related to surface runoff estimation. Image 1 • CN-China was developed by revising the original USDA curve number method. • Rainfall-runoff monitoring data covering major land cover types were collected. • Adjusted CN values are largely different from CN look-up table developed by USDA. • CN-China is more suitable for runoff estimation in complex natural conditions. [ABSTRACT FROM AUTHOR]

Sewage sludge (SS) is commonly used as agricultural fertilizer worldwide. However, the toxic metal(loid)s in SS raises concerns about soil contamination and the potential risks to human health. This study, conducted since 2007 on the North China Plain, examines the impact of SS use on crops. An experiment was designed with five treatments: conventional fertilization (CK) and four levels of SS application (W1, W2, W3, and W4: 4.5, 9.0, 18.0, and 36.0 t ha -1 , respectively). Soil concentrations of eight toxic metal(loid)s (Zn, Cu, Cr, Cd, Ni, Pb, As, and Hg) were analyzed to assess pollution risk using various indices. Health risks associated with maize and wheat grains were also evaluated. Additionally, the impact of long-term SS application on crop yield, soil quality, and human health within a wheat-maize rotation system was examined. SS application increased wheat and maize yields by 5.37 to 19.08 % and 6.97 to 17.94 %, respectively, across treatments W2 to W4. Despite the toxic metal(loid)s in the grains remaining within safe limits, their concentrations showed an upward trend, especially under the W4 treatment. Moreover, SS application significantly increased the soil Zn, Cu, Cr, Cd, Pb, and Hg levels (P < 0.05) without exceeding the national standards. The geo-accumulation index values revealed rising pollution levels for Zn, Cu, Cd, and Hg, which shifted from no contamination to moderate contamination and then to moderate-to-high contamination, yet the overall pollution level remained safe. Soil ecological risks increased from moderate to serious, with Hg posing the greatest risk, particularly under the W4 treatment. Long-term crop intake from the area significantly exposed children and adults to As, contributing 42.12 % and 34.62 % to hazard index (HI), respectively. The HI values for toxic metal(loid)s in these grains surpassed one in both age groups, suggesting health risks from long-term SS cultivated crops., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Water diverted from rivers for irrigation areas often contains large amounts of nitrogen (N), which is frequently overlooked and its role in contributing to N pollution is unknown. To investigate the influence of water diversion on N in different systems within irrigation areas, we developed and optimized the N footprint model, taking into account the N carried by irrigation water diversion and drainage in irrigated areas. This optimized model can serve as a reference for evaluating N pollution in other irrigated areas. By analyzing 29 years (1991-2019) of statistical data from a diverted irrigation area in Ningxia Hui Autonomous Region (Ningxia), China, the study assessed the contribution of water diversion to N in agriculture, animal husbandry, and human domestic activities. The results demonstrated that water diversion and drainage accounted for 10.3% and 13.8% in whole system, of the total N input and output in Ningxia, highlighting the potential N pollution risks associated with these activities. Additionally, the use of fertilizers in the plant subsystem, feed in the animal subsystem, and sanitary sewage in the human subsystem represented the main sources of N pollution in each subsystem. On a temporal scale, the study found that N loss increased year by year before reaching a stable level, indicating that N loss had reached its peak in Ningxia. The correlation analysis suggested that rainfall could regulate N input and output in irrigated areas by showing a negative correlation with water diversion, agricultural water consumption, and N from irrigated areas. Moreover, the study revealed that the amount of N brought by water diverted from rivers for irrigation should be taken into account when calculating the amount of fertilizer N required in the irrigation area., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Excess phosphorus (P) leached from high fertiliser input cropping systems in northern China is having detrimental effects on water quality. Before improved management can be directed at specific soils and cropping system types estimates of P leached loss apportionment and mitigation potentials across the main soil (fluvo-aquic soil, FAS; cinnamon soil, CS; black soil, BS) areas and cropping systems (protected vegetable fields, PVFs; open vegetable fields, OVFs; cereal fields, CFs) are needed. The present study designed and implemented conventional fertilisation and low input system trials at 75 sites inclusive of these main soils and cropping system types in northern China. At all sites, a uniform lysimeter design (to 0.9 m depth) enabled the collection and analysis of leachate samples from 7578 individual events between 2008 and 2018. In addition, site-specific static and dynamic activity data were recorded. Results showed that annual total phosphorus (TP) leached losses across the main soil areas and cropping systems were 4.99 × 10 6  kg in northern China. A major finding was PVFs contributed to 48.5% of the TP leached losses but only accounted for 5.7% of the total cropping areas. The CFs and OVFs accounted for 40.3% and 11.2% of the TP leached losses, respectively. Across northern China, the TP leached losses in PVFs and OVFs were greatest in FAS areas followed by CS and BS areas. The higher TP leached losses in FAS areas were closely correlated with greater P fertiliser inputs and irrigation practices. From a management perspective in PVFs and OVFs systems, a decrease of P inputs by 10-30% would not negatively affect yields while protecting water quality. The present study highlights the importance of decreasing P inputs in PVFs and OVFs and supporting soil P nutrient advocacy for farmers in China., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The excessive application of manure has caused a high load of phosphorus (P) in the North China Plain. Having an understanding of how manure application affects soil P changes and its transport between different soil layers is crucial to reasonably apply manure P and reduce the associated loss. Based on our 28-year field experiments, the compositions and changes of P species and the risk of P loss under excessive manure treatments were investigated, i.e., no fertilizer (CK), mineral fertilizer NPK (NPK), NPK plus 22.5 t ha -1 yr -1 swine manure (LMNPK), and NPK plus 33.75 t ha -1 yr -1 swine manure (HMNPK). Manure application increased the content of orthophosphate and myo-inositol hexaphosphate (myo-IHP), especially the orthophosphate content exceeded 95%. The amount of orthophosphate in manure and the conversion of organic P to inorganic P in soil were the main reasons for the increased soil orthophosphate. Compared with NPK treatment, soil microbial biomass phosphorus and alkaline phosphatase activity in LMNPK and HMNPK treatments significantly increased. Compared with NPK treatment, a high manure application rate under HMNPK treatment could increase the abundance of organic P-mineralization gene phoD by 60.0% and decrease the abundance of inorganic P-solubilization gene pqqC by 45.9%. Due to the continuous additional manure application, soil P stocks significantly increased under LMNPK and HMNPK treatments. Furthermore, part of the P has been leached to the 60-80 cm soil layer. Segmented regression analysis indicated that CaCl 2 -P increased sharply when Olsen-P was higher than 25.1 mg kg -1 , however the content of Olsen-P did not exceed this value until 10 years after consecutive excessive manure application. In order to improve soil P availability and decrease the risk of P loss, the manure application rate should vary over time based on soil physicochemical conditions, plants requirements, and P stocks from previous years., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The use of livestock manure as a substitution for synthetic nitrogen (N) fertilizers is recommended to improve the sustainable use of manure nutrients and alleviate the adverse impacts of synthetic N fertilizers on the environment. A thorough understanding of how such substitutions affect reactive N losses and greenhouse gas (GHG) emissions in cereal production systems in the North China Plain (a main livestock production region in China), is needed to achieve an environmental friendly and sustainable production. Based on a long-term field experiment, different manure/chemical fertilizer treatments were designed, i.e., non-fertilization control (CK), chemical fertilizers alone (NPK), and manure substitution for chemical N fertilizers (with equivalent N rate; NPKP, 50% N from pig manure; NPKC, 50% N from chicken manure). Crop yield, nitrogen use efficiency (NUE), soil fertility, N losses, and GHG emissions were chosen as prominent indicators to evaluate the consequences of manure substitutions for N-based fertilizers. The replacement of synthetic fertilizers by livestock manure decreased NO 3 -N leaching and NH 3 volatilization by 46.2% and 5.61-22.2%, respectively, while sustained the crop yields and improved NUE. However, both NPKP and NPKC treatments did not have any impact on N 2 O and CO 2 mitigation. Compared with NPK, NPKC and NPKP meaningfully increased SOC by 9.56% and 19.6%, respectively. More specifically, NPKC increased TN content by 14.7% (P < 0.05) compared to NPK treatment. The results showed that 50% substitution of manure for synthetic N fertilizers is a potential option in maize production systems to decrease N losses (including NH 3 , N 2 O emissions and N leaching) by approximately 45% (42.8-48.1%). However, only 1.81% of the total farmers surveyed (i.e., 16,595) have being applied livestock manure for maize cultivation in the North China Plain. Therefore, famers in this plain should be encouraged to use manure to improve ecological aspects of cereal cultivation and decrease the associated environmental pollutions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Plastic pollution is a global concern given its prevalence in aquatic and terrestrial ecosystems. Studies have been conducted on the distribution and impact of plastic pollution in marine ecosystems, but little is known on terrestrial ecosystems. Plastic mulch has been widely used to increase crop yields worldwide, yet the impact of plastic residues in cropland soils to soil health and crop production in the long term remained unclear. In this paper, using a global meta-analysis, we found that the use of plastic mulch can indeed increase crop yields on average by 25%-42% in the immediate season due to the increase of soil temperature (+8%) and moisture (+17%). However, the unabated accumulation of film residues in the field negatively impacts its physicochemical properties linked to healthy soil and threatens food production in the long term. It has multiple negative impacts on plant growth including crop yield (at the mean rate of -3% for every additional 100 kg/ha of film residue), plant height (-2%) and root weight (-5%), and soil properties including soil water evaporation capacity (-2%), soil water infiltration rate (-8%), soil organic matter (-0.8%) and soil available phosphorus (-5%) based on meta-regression. Using a nationwide field survey of China, the largest user of plastic mulch worldwide, we found that plastic residue accumulation in cropland soils has reached 550,800 tonnes, with an estimated 6%-10% reduction in cotton yield in some polluted sites based on current level of plastic residue content. Immediate actions should be taken to ensure the recovery of plastic film mulch and limit further increase in film residue loading to maintain the sustainability of these croplands., (© 2020 John Wiley & Sons Ltd.)

In the wheat-maize rotation cultivation system in northern China, excessive irrigation and over-fertilization have depleted groundwater and increased nitrogen (N) losses. These problems can be addressed by optimized N fertilization and water-saving irrigation. We evaluated the effects of these practices on greenhouse gas emissions (GHG), net profit, and soil carbon (C) sequestration. We conducted a field experiment with flood irrigation (FN0, 0 kg N ha -1 yr -1 , FN600, 600 kg N ha -1 yr -1 ) and drip fertigation treatments (DN0, 0 kg N ha -1 yr -1 ; DN420, 420 kg N ha -1 yr -1 ; DN600, 600 kg N ha -1 yr -1 ) in 2015-2017. Compared with FN600, DN600 decreased direct GHGs (N 2 O + CH 4 ) emissions by 21%, and increased the net GHG balance, GHG intensity, irrigation water-use efficiency (IWUE), and soil organic C content (ΔSOC) by 13%, 12%, 88%, and 89.8%, respectively. Higher costs in DN600 (for electricity, labour, polyethylene) led to a 33.8% lower net profit than in FN600. Compared with FN600, DN420 reduced N and irrigation water by 30% and 46%, respectively, which increased partial factor productivity and IWUE (by 49% and 94%, respectively), but DN420 did not affect GHG mitigation or net profit. Because lower profit is the key factor limiting the technical extension of fertigation, financial subsidies should be made available for farmers to install fertigation technology.