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In order to address the increasingly prominent issues of water resource protection and agricultural non-point source pollution in the Erhai Lake Basin, this study conducted a two-year field experiment in Gusheng Village, located in the Erhai Lake Basin. In 2022, two irrigation treatments were set up: conventional flooding irrigation (CK) and controlled irrigation (C), with three replicates for each treatment. In 2023, aiming to enhance the utilization rate of rainwater resources and reduce the direct discharge of dry-farming tailwater from upstream into Erhai Lake. The paddy field was used as an ecological storage basin, and the water storage depth of the paddy field was increased compared to the depth of 2022. Combined with the deep storage of rainwater, the dry-farming tailwater was recharged into the paddy field to reduce the drainage. In 2023, two water treatments, flooding irrigation with deep storage and controlled drainage (CKCD) and water-saving irrigation with deep storage and controlled drainage (CCD) were set up, and each treatment was set up with three replicates. The growth and physiological index of rice at various stages were observed. Nitrogen leaching of paddy field in surface water, soil water, and groundwater under different water treatments after tillering fertilizer were observed. The research results show that the combined application of organic and inorganic fertilizers under organic planting can provide more reasonable nutrient supply for rice, promote dry matter accumulation and other indices, and also reduce the concentration of NH4+-N in surface water. Compared with CK, the yield, 1000-grain weight, root-to-shoot ratio, and leaf area index of C are increased by 4.8%, 4.1%, 20.9%, and 9.7%, respectively. Compared with CKCD, the yield, 1000-grain weight, root-to-shoot ratio, and leaf area index of CCD are increased by 6.5%, 3.8%, 19.6%, and 21.9%, respectively. The yield in 2023 is 19% higher than that in 2022. Treatment C can increase the growth indicators and reduce the net photosynthetic rate to a certain extent, while CCD rain-flood storage can alleviate the inhibition of low irrigation lower limit on the net photosynthetic rate of rice. Both C and CCD can reduce nitrogen loss and irrigation amount in paddy fields. CCD can reduce the tailwater in the Gusheng area of the Erhai Lake Basin to Erhai Lake, and also can make full use of N, P, and other nutrients in the tailwater to promote the formation and development of rice. In conclusion, the paddy field rain-flood storage methodology in the Erhai Lake Basin can promote various growth and physiological indicators of rice, improve water resource utilization efficiency, reduce direct discharge of tailwater into Erhai Lake, and decrease the risk of agricultural non-point source pollution. [ABSTRACT FROM AUTHOR]

This document provides a list of references related to potato cultivation and fertilizer management. The references cover a range of topics including the effects of water and nitrogen management on potato biomass accumulation, the use of controlled-release fertilizers, and the impact of different fertilization regimes on potato crop performance. The document also includes studies on the yield and quality of potatoes under different growing conditions, the use of mulching to improve tuber yield and nitrogen use efficiency, and the impact of delayed irrigation on potato yield and growth parameters. Additionally, there are references on sustainable and profitable nitrogen fertilization management in potato cultivation. [Extracted from the article]

Dairy slurry could be a significant source of nitrogen (N) for plants, but mismanagement can lead to atmospheric ammonia losses or nitrate leaching into groundwater. To make the use of dairy slurry efficient and reasonable, the loss of N pollution to the environment should be reduced. We used repacked lysimeters to comprehensively determine ammonia emission and N leaching losses in an alfalfa–soil system. The application of dairy slurry had no significant effect on alfalfa yield at the same rate of N application in comparison to chemical fertilizer, and adding humic acids significantly increased yield by about 12%. However, the application of dairy slurry increased the ammonia emission rate significantly, leading to an increase in the cumulative amount of ammonia emission, while the addition of humic acids reduced the ammonia emissions by 11%. Chemical fertilizer and dairy slurry application significantly increased nitrate leaching compared to the control treatment, while the addition of humic acids can significantly reduce ammonium N leaching. Dairy slurry was proven to be as effective as chemical N fertilizer in achieving the optimum biomass, and adding humic acids can significantly reduce N loss to the atmosphere and groundwater. This study showed the possibility of replacing chemical fertilizer with dairy slurry in alfalfa production and the advantages of humic acids' addition to alfalfa to maintain production yield and improve environmental friendliness. [ABSTRACT FROM AUTHOR]

Plantain (Plantago lanceolata L.) has recently been thrust into the limelight as a potential tool for mitigating nitrogen losses from the New Zealand pastoral environment. It is claimed to possess characteristics to reduce nitrogen leaching through both animal and soil-based mechanisms. This review examines the use of plantain in New Zealand pastures and the research that has led to these claims. The focus is on the evaluation of scientific evidence for the mechanisms through which plantain is proposed to reduce nitrate leaching, as well as the research on the implementation of plantain into pastoral farm systems. Plantain clearly increases the urination of grazing animals; a trait not unique to plantain. This review concludes that many research studies supporting the beneficial impact of plantain do not stand up against scientific scrutiny associated with methodology and interpretation of data. It is recommended more research should be undertaken on other pasture species and management tools, that may be more effective alternatives to plantain for nitrogen mitigation in pastures. [ABSTRACT FROM AUTHOR]

Purpose: The overuse of nitrogen fertilizers, most commonly urea, is ultimately having a serious impact on the environment through nitrogen leaching. Biochar addition is considered to be a promising measure for mitigating nitrogen leaching. However, whether biochar has a long-term effect is unclear. Moreover, Mg-modified biochar (Mg-biochar) has more excellent physicochemical and surface properties than original biochar, and it has been widely used in water pollution remediation; however, its effect on soil nitrogen leaching is still uncertain. Methods: The optimal Mg-biochar was selected by adsorption test. In the subsequent soil column simulation experiment, a total of five treatment groups: nitrogen fertilizer (CK), nitrogen fertilizer + fresh biochar (BC), nitrogen fertilizer + Mg-biochar (MGBC), nitrogen fertilizer + freeze-thaw aged biochar (DBC), and nitrogen fertilizer + freeze-thaw aging Mg-biochar (DMGBC) were set up to explore the distribution of nitrogen in the soil-leaching solution-plant system. Results: In this study, biochar modified by 2 mol/L MgCl2 was chosen to be the optimal Mg-biochar. Compared with the CK, BC reduced the soil nitrogen leaching by 16.96% and increased the soil nitrogen content and cabbage nitrogen absorption by 1.65% and 114.19%, respectively. Mg-biochar had higher nitrogen retention ability than original biochar, and after freeze-thaw aging, biochar maintained or even improved nitrogen retention ability. Conclusion: The biochar addition had good nitrogen retention ability, and Mg-biochar performed better, and they showed long-term effect on mitigating soil nitrogen leaching. Meanwhile, based on the law of conservation of matter, biochar addition also reduced gaseous nitrogen loss. [ABSTRACT FROM AUTHOR]

The study aimed to investigate yield characteristics, nitrogen uptake, and leaching losses of spring maize under different levels of nitrogen reduction and to provide a theoretical basis for the reasonable application of nitrogen fertilizer to spring maize in the Ningxia Yellow River irrigation area. A field experiment was conducted for two consecutive years from 2021 to 2022 in the Ningxia diversion irrigation district. The experiment used Centaur 1225 as the maize test variety in a seepage pond. Five nitrogen levels with nitrogen applications of 420 kg·hm-2 (N-420), 14.29%(N-360), 35.71%(N-270), 57.14 %(N-180)N reduction, and no N application treatments (CK), were included in the study. The yield, nitrogen uptake and utilization, and N leaching losses of spring maize were measured and analyzed. No significant difference(P<0.05)was observed in crop yield between crops grown under conventional fertilizer application and those grown under 14.29% N reduction treatment. A reduction in yield was observed under 35.71% N reduction treatment compared with conventional fertilizer treatment. Compared with the conventional fertilizer application treatment, 35.71% N reduction and 14.29% N reduction treatments reduced grain yield in 2021 by only 8.60% and 3.59%, respectively. In 2022, 35.71% N reduction reduced grain yield by 11.46% whereas 14.29% N reduction treatment increased the seed yield by 1.42% compared with the conventional fertilizer treatment. The utilization and agronomic efficiency of N fertilizer and the above-ground nitrogen harvest index data for both years showed that they were higher for the 35.71% N reduction treatment than the 14.29% N reduction and the conventional fertilizer treatments. Moreover, the N fertilizer bias productivity gradually decreased with increasing N application. Compared with the bias productivity of 57.14% N reduction treatment, the corresponding values for 35.71% N reduction, 14.29% N reduction, and conventional fertilizer treatments decreased by 19.57%, 33.81%, and 42.59%, respectively. The apparent leaching coefficient of nitrogen fertilizer increased with the increase of nitrogen application, and the total nitrogen leaching losses were reduced by 42.51% and 18.09% in the 35.71% and 14.29% N reduction treatments, respectively, compared with the losses in the conventional nitrogen application treatment. Under each treatment, nitrate-nitrogen was the main form of nitrogen leaching, accounting for 45.50%-54.68% of the total leached nitrogen. Correlation analysis between nitrogen application and total nitrogen leaching losses showed that they were positively correlated, and the total nitrogen leaching losses increased exponentially(R² =0.998 6)with the increase of nitrogen application. Compared with conventional N application, a 35.71% reduction in N application reduced spring maize yield by 10.03% and N leaching by 42.51%, which improved the agronomic efficiency and biased productivity of N fertilizer. Hence, N application of 270 kg·hm-2 can be a reasonable choice to reconcile the yield and environmental safety of spring maize in the Yellow River irrigation area. [ABSTRACT FROM AUTHOR]

Soil organic carbon (SOC) sequestration in agricultural soils is an important tool for climate change mitigation within the EU soil strategy for 2030 and can be achieved via the adoption of soil management strategies (SMS). These strategies may induce synergistic effects by simultaneously reducing greenhouse gas (GHG) emissions and/or nitrogen (N) leaching. In contrast, other SMS may stimulate emissions of GHG such as nitrous oxide (N2O) or methane (CH4), offsetting the climate change mitigation gained via SOC sequestration. Despite the importance of understanding trade‐offs and synergies for selecting sustainable SMS for European agriculture, knowledge on these effects remains limited. This review synthesizes existing knowledge, identifies knowledge gaps and provides research recommendations on trade‐offs and synergies between SOC sequestration or SOC accrual, non‐CO2 GHG emissions and N leaching related to selected SMS. We investigated 87 peer‐reviewed articles that address SMS and categorized them under tillage management, cropping systems, water management and fertilization and organic matter (OM) inputs. SMS, such as conservation tillage, adapted crop rotations, adapted water management, OM inputs by cover crops (CC), organic amendments (OA) and biochar, contribute to increase SOC stocks and reduce N leaching. Adoption of leguminous CC or specific cropping systems and adapted water management tend to create trade‐offs by stimulating N2O emissions, while specific cropping systems or application of biochar can mitigate N2O emissions. The effect of crop residues on N2O emissions depends strongly on their C/N ratio. Organic agriculture and agroforestry clearly mitigate CH4 emissions but the impact of other SMS requires additional study. More experimental research is needed to study the impact of both the pedoclimatic conditions and the long‐term dynamics of trade‐offs and synergies. Researchers should simultaneously assess the impact of (multiple) agricultural SMS on SOC stocks, GHG emissions and N leaching. This review provides guidance to policymakers as well as a framework to design field experiments and model simulations, which can address knowledge gaps and non‐intentional effects of applying agricultural SMS meant to increase SOC sequestration. [ABSTRACT FROM AUTHOR]

Commercial production of ornamental plants in soilless substrate poses significant risk of nutrient pollution, and development of management practices to reduce N and P leaching is urgently needed. This study aims to determine if zeolite amendment reduces the leaching of nitrate nitrogen (NO3-N), ammonium nitrogen (NH4-N), and phosphorus (P) from soilless substrates incorporated with controlled-release fertilizers (CRFs). Tissue culture liners of a popular ornamental plant, peace lily (Spathiphyllum 'Viscount'), were transplanted singly into 15-cm plastic pots containing the substrate amended with two zeolites (SC and XY), each at three rates of 10, 20, and 50 g per pot, respectively. Plants were grown in a shaded greenhouse for three months and irrigated at a 0.2 leachate fraction. Collected leachates were analyzed for NH4-N, NO3-N, and P. Results showed that both zeolites reduced N and P leaching with the 50 g per pot rate performing the best. Compared with the control, substrate amended with XY zeolite at 50 g per pot reduced NO3-N leaching by 38.34%, NH4-N leaching by 44.59%, and P leaching by 38.85%; substrate amended with SC zeolite at 50 g reduced NO3-N leaching by 52.42%, NH4-N leaching by 39.19%, and P leaching by 36.36%. Dry weights of plants grown in zeolite-amended substrates were higher than in the control substrate. This study highlights that zeolite amendment to soilless substrate is a sustainable practice for improving container plant production, while reducing N and P leaching and protecting our natural environment. [ABSTRACT FROM AUTHOR]

The overuse of fertilizers in open-field tomato leads to soil deterioration through nutrient leaching and increases the risk of agricultural non-point source contamination. Currently, the combined effects of different fertilization methods on soil nitrogen leaching and tomato production are still unclear. Therefore, the most effective fertilization method for open-field tomato should be discovered by examining how different fertilization methods affected tomato yield and quality, nitrogen use efficiency (NUE), and soil nitrogen leaching. Compared with CK (no fertilization), fertilization significantly increased the yield, total sugar (TS), total soluble solids (TSS), and vitamin C (vC) contents of fruits (p < 0.05), and OPT (optimal fertilization, controlled release nitrogen application, 240 kg ha−1) had the largest effect on increasing yield, quality, and net profit. However, when the fertilizer application rate reached 375 kg ha−1, these indices decreased. Nitrogen leaching concentrations, leaching amount, and titratable acids (TAs) increased with increased nitrogen application rates. Compared with other treatments, OPT reduced the total leaching amounts of total nitrogen (TN), nitrate nitrogen (NO3−-N), and ammonia nitrogen (NH4+-N) by 30.09–51.79%, 24.89–50.03%, and 30–65%, respectively. Principal component analysis (PCA) showed that OPT achieved the highest overall score in terms of yield, quality, and nitrogen leaching conditions. The partial least squares path modeling (PLS-PM) further reveals that applications of high amounts of nitorigen have a positive effect on soil nitrogen leaching. The amount of nitrogen leaching vegetatively affects tomato yield and quality, while plant uptake of nitrogen positively affects tomato production. These findings confirm the importance of using controlled-release fertilizers and reducing nitrogen inputs to control nitrogen leaching and enhance open-field tomato yields. [ABSTRACT FROM AUTHOR]

Atmospheric nitrogen (N) deposition and climate change are transforming the way N moves through dryland watersheds. For example, N deposition is increasing N export to streams, which may be exacerbated by changes in the magnitude, timing, and intensity of precipitation (i.e., the precipitation regime). While deposition can control the amount of N entering a watershed, the precipitation regime influences rates of internal cycling; when and where soil N, plant roots, and microbes are hydrologically coupled via diffusion; how quickly plants and microbes assimilate N; and rates of denitrification, runoff, and leaching. We used the ecohydrological model RHESSys to investigate (a) how N dynamics differ between N‐limited and N‐saturated conditions in a dryland watershed, and (b) how total precipitation and its intra‐annual intermittency (i.e., the time between storms in a year), interannual intermittency (i.e., the duration of dry months across multiple years), and interannual variability (i.e., variance in the amount of precipitation among years) modify N dynamics and export. Streamflow nitrate (NO3−) export was more sensitive to increasing rainfall intermittency (both intra‐annual and interannual) and variability in N‐limited than in N‐saturated model scenarios, particularly when total precipitation was lower—the opposite was true for denitrification which is more sensitive in N‐saturated than N‐limited scenarios. N export and denitrification increased or decreased more with increasing interannual intermittency than with other changes in precipitation amount. This suggests that under future climate change, prolonged droughts that are followed by more intense storms may pose a major threat to water quality in dryland watersheds. Plain Language Summary: Fossil fuel combustion and industrial agriculture have increased atmospheric nitrogen (N) pollution. Atmospheric N can travel with prevailing winds and be deposited on soil surfaces in terrestrial ecosystems. This can in turn increase N cycling and export to aquatic ecosystems, where excess N acts as a pollutant. The timing and amount of rainfall can influence how much N is transported from terrestrial to aquatic ecosystems, but it remains unclear how future N deposition and precipitation patterns will interact to influence stream water quality and drinking water security. To address this, we used a simulation model to investigate (a) how changes in the timing and/or amount of precipitation influence N export from watersheds, and (b) how the effects of precipitation change with increased atmospheric N deposition. We found that N export to streams increases with precipitation intermittency and variability, particularly when N deposition is low. Under high N deposition, export to streams is substantially elevated, regardless of precipitation timing. Our findings suggest that under future climate change, prolonged droughts that are followed by more intense storms may increase hydrologic N export and pose a major threat to water quality in dryland watersheds. Key Points: Simulating how N deposition interacts with precipitation seasonality can enable us to better predict when dryland watersheds become N‐saturatedAs rainfall regimes become more intermittent and/or variable, streamflow nitrate export is likely to increase, particularly when a watershed is N‐limitedUnder future climate change in drylands, prolonged droughts that are followed by more intense storms may pose a major threat to water quality [ABSTRACT FROM AUTHOR]

The tree species composition has a significant impact on the biogeochemical cycle of forest ecosystems, which in turn affects nutrient leaching and stream water quality. We have formulated a hypothesis that nutrient leaching varies depending on the tree species composition owing to the properties of surface soil chemistry characterized by the tree species composition. To test this hypothesis, we have collected soil water samples below the root zone in Japanese cedar plantations (CF) and natural forests (NF) and compared nutrient leaching. We analyzed major ion chemical characteristics, net N mineralization, and net nitrification in the surface soil (A layer) to determine possible causes for differences in nutrient leaching. Our results revealed that calcium (Ca2+) and nitrate (NO3−) concentrations in soil water below the root zone were significantly higher in CF than in NF. Additionally, the Ca2+ and NO3− contents in surface soil were higher in CF than in NF, which may explain the higher concentrations of Ca2+ and NO3− in soil water in CF. In contrast, there was no significant difference in soil net nitrification rates between CF and NF. Correlations between NO3− and Ca2+ concentrations in soil solution suggest that the higher availability of Ca2+ from surface soils in CF could partially account for the higher NO3− leaching from CF. Our study suggests that the properties of surface soil chemistry characterized by the tree species composition are responsible for causing the differences in nutrient leaching. [ABSTRACT FROM AUTHOR]

Fertilizer‐intensive sugarcane plantations are expanding in sub‐Saharan Africa (SSA) amidst increased groundwater pollution and carbon footprint concerns. Yet, the impact of nitrogen (N) levels on N losses, productivity and profitability in these plantations remains unclear. To address this gap, we conducted a completely randomized design experiment in a Ugandan sugarcane plantation using three N fertilization rates (low, standard and high) as treatments. N leaching under the different treatments was determined using the average drainage fluxes across a 1‐m‐layered profile which we estimated with a suite of pedotransfer functions (PTFs) and leachate N concentrations from suction cup lysimeters. Soil nitrous oxide fluxes were determined using static vented chamber bases and gas chromatography. Partial factor crop productivity was estimated from the average field fresh weight under each treatment and the amount of N fertilizer applied, while the return on investment was determined from the factory price of the field fresh weight and the market price of fertilizers. Our findings indicate that three out of five PTFs effectively estimated soil hydraulic properties at our test site, based on the close match between measured and predicted soil matric potential values. Notably, N leaching at low and standard N rates were comparable but significantly lower than at higher‐than‐standard N rates. Additionally, we measured comparable soil nitrous oxide emissions and field fresh weight but partial factor productivity and return on investment declined along the fertilizer intensification gradient. In conclusion, the study demonstrates the promising application of certain PTFs in N‐leaching modelling in the data‐scarce SSA. Furthermore, obtaining comparable field fresh weight with minimal N losses at lower‐than‐standard N rates presents an opportunity to mitigate groundwater pollution and greenhouse gas emissions. However, the potential impact of the switch from standard to low N rates on soil organic carbon stocks and sugarcane yields warrants further investigation. [ABSTRACT FROM AUTHOR]

Mitigation practices for nitrogen leaching losses from livestock agriculture are needed to protect freshwater quality and increase the efficiency of agricultural production. Within New Zealand, the most common pasture type is a two-species mix of perennial ryegrass (Lolium perenne) and white clover (Trifolium repens). Ecological theory suggests that increasing species and functional diversity improves ecosystem function, including nitrogen (N) retention. Use of more diverse pasture types, including a mix of pasture grasses, legumes and other forbs, particularly plantain (Plantago lanceolata), with functional traits, including winter activity, deep-rooting, N fixation, and biological inhibition of nitrification in the soil, is a potential mitigation practice that requires further verification with long-term field measurements. Here we utilize a network of large lysimeters to make field-based measurements of N leaching from 5–8 species diverse pasture, including plantain, under a range of soil, climate and management conditions, for comparison with losses from traditional ryegrass-clover pasture. Over 3 years of measurements, leaching from fully established diverse pasture was 2–80 kg N ha−1 y−1. No differences were observed in dry matter production or N leaching of diverse pasture compared to ryegrass-clover lysimeters. Large losses, up to 120 kg N ha−1, were observed during periods when pasture was not fully established, including cultivation and sowing of new pasture, depending on season. Timing of management activities could be optimized to minimize these losses. These data provide critical assessment of diverse pasture as a mitigation approach for reducing N losses. Further work on diverse pastures should include higher diversity mixes as well as consideration of animal mediated effects of diverse pasture diets on N inputs.

Excessive nitrogen (N) fertilization and irrigation prevail in irrigated agriculture worldwide. However, little information is available that systematically evaluates grain yield, plant N uptake, residual soil NO3−-N (RSN), and N leaching under different irrigation–N regimes in an irrigated maize production system. To address such agronomic and environmental issues, a 6-year in situ lysimeter field trial was conducted in the Hetao Irrigation District of China with five treatments: 1) conventional irrigation (3,900 m3/ha) and local farmer fertilizer N rate (490 kg ha−1) (CON); 2) conventional irrigation and the recommended fertilizer N rate (420 kg ha−1) (RN); 3) deficit irrigation (2,730 m3/ha) and the recommended fertilizer N rate (SRN); 4) deficit irrigation and the recommended fertilizer N rate (with ∼ 10 % organic fertilizer N substitution) (SMN); and 5) conventional irrigation and controlled-release N fertilizer (270 kg ha−1) (CRF). Maize yield was not significantly different across treatments in 2015–2020. Averaged across years, SMN, SRN, and CRF significantly increased plant N uptake compared with that in CON by 28.84 %, 19.15 %, and 17.53 %, respectively. Residual soil NO3−-N at 0–90 cm was ranked as SRN > CON ≈ SMN > RN > CRF, whereas cumulative N in leachate from 2015–2020 (Nloss) in CON was 86.2 % to 187.1 % higher than that in other treatments. The Nloss in SRN was equivalent to that in RN and SMN, but Nloss in SMN decreased significantly compared with that in RN, indicating additive benefits of deficit irrigation and organic input on reducing N leaching. Structural equation modelling revealed that irrigation had greater effects on plant N uptake than those of fertilization, whereas N rate had a greater total effect on N leaching than that of irrigation. Overall, rampant excessive irrigation and N fertilization by farmers can be substantially reduced while maintaining grain yield and mitigating N leaching loss, with further benefits gained by applying controlled-release N fertilizer and manure in irrigated maize production.

Introduction: Despite various efforts to reduce nitrogen leaching from agricultural land, the permissible nitrate concentrations in groundwater have often been exceeded in the past. Intensive farming is often seen as the cause of the deterioration in water quality. Therefore, the present lysimeter study aimed to quantify nitrogen (N) leaching at different N fertilization levels for the agricultural land use systems of arable land and grassland to derive suitable management measures for improving groundwater quality. Methods: The effects of three different of mineral fertilization treatments (50%, 100%, and 150%) in arable land and grassland use on four distinct soil types (loamy sand, sand, loam, loess) concerning seepage formation, nitrogen concentrations, nitrogen loads, drymatter yields and nitrogen balances were tested. The study was conducted at the lysimeter facility of the Helmholtz Centre of Environmental Research - UFZ at Falkenberg (northeast Germany). Twenty-four non-weighable lysimeters with a surface area of 1 m² and a depth of 1.25 m were managed as grassland and arable land with three different fertilization treatments since 1985. Results and Discussion: For arable land use, N leaching differed between the studied soil types, with the highest N loads from the sand (36.6 kg ha-1 yr-1) and loamy sand (30.7 kg ha-1 yr-1) and the lowest N loads fromloess (12.1 kg ha-1 yr-1) and loam soil (13.1 kg ha-1 yr-1). In contrast to grassland use, a reduction of N fertilization level by 50 % did not result in reduced N leaching for arable land, whereas a maximal 29% reduced dry matter yields was observed. An increase of N fertilization by 50 % did not cause significant enhanced N leaching at arable land use. Soil-and management-related factors (soil type, texture, soil tillage, crop rotation, and others)mask the effect of increased N fertilization rates in arable land using lysimeters. For arable land use, a reduction of N fertilizer levels as the only measure was insufficient to reduce NO3- leaching, and other strategies besides N fertilization levels are required to improve groundwater quality. Measures should be targeted to reduce N losses by mineralization processes. [ABSTRACT FROM AUTHOR]

The application of compost to agricultural soils can increase nutrient leaching, causing several environmental problems. Conversely, proper management of compost application can reduce environmental risks. Agronomical trials were conducted in greenhouses in Morocco to compare the effects of varying compost application rates, types, and maturity, as well as the number of growing days, on nutrient availability and nitrate leaching in a loamy sandy soil. Additionally, the study examined the impacts of these factors on soil physical and chemical characteristics. The compost used in this study was derived from a combination of two cost-effective materials, municipal waste, and poultry manure. Tomato plants were cultivated in pots amended with compost over a period of 65 days. The soils were treated with eight composts (plus a control) obtained from municipal solid waste (MSW) mixed with poultry manure (PM) at two ratios, 3:2 and 2:3 weight weight−1 (ww−1) (C1 and C2, respectively), used at two different ages (105 days and 173 days) and at two doses (32.5 g pot−1 and 65 g pot−1, equivalent to 40 Mg ha−1 and 80 Mg ha−1). Two simulated leaching events (the first after planting and the second at harvest) were performed. The concentration of chemical oxygen demand (COD) and total Kjeldahl nitrogen (TKN) in leachate varied with the number of growing days and increased in the leachate of the non-amended soil after planting. At both sampling times, compost C1, aged 173 days (d), significantly decreased COD in the leachate compared to compost C1 aged 105 d. Compost increased nitrate leaching compared with the non-amended soil. Nitrogen leaching was primarily in the form of nitrate, ranging from 61% to 78% over the whole experimental period. Compost also decreased leachate concentrations of iron (Fe) and chromium (Cr), for other metals, such as cobalt (Co) and nickel (Ni), values were very low. Moreover, compost increased total organic carbon by up to twofold at both sampling times, with the most substantial increase observed with a dose of 65 g pot−1 of compost C2 (aged 105 days). Most compost treatments also increased available phosphorus (P), inorganic nitrogen (N), total nitrogen (TNK), cation exchange capacity (CEC), and electrical conductivity (EC) at both sampling times but had no effect on pH. The metal content in the soil exhibited a decrease compared to the control soil. Overall, our study suggests that nitrogen leaching can be reduced by optimizing compost rates, properties, and stability to synchronize with crop needs. [ABSTRACT FROM AUTHOR]

Climate change and nitrogen (N) pollution are altering biogeochemical and ecohydrological processes in dryland watersheds, increasing N export, and threatening water quality. While simulation models are useful for projecting how N export will change in the future, most models ignore biogeochemical "hotspots" that develop in drylands as moist microsites in the soil become hydrologically disconnected from plant roots when soils dry out. These hotspots enable N to accumulate over dry periods and rapidly flush to streams when soils wet up. To better project future N export, we developed a framework for representing hotspots using the ecohydrological model RHESSys. We then conducted a series of virtual experiments to understand how uncertainties in model structure and parameters influence N export to streams. Modeled N export was sensitive to three major factors (a) the abundance of hotspots in a watershed: N export increased linearly and then reached an asymptote with increasing hotspot abundance; this occurred because carbon and N inputs eventually became limiting as hotspots displaced vegetation cover, (b) the soil moisture threshold required for subsurface flow from hotspots to reestablish: peak streamflow N export increased and then decreased with an increasing threshold due to tradeoffs between N accumulation and export that occur with increasingly disconnected hotspots, and (c) the rate at which water diffused out of hotspots as soils dried down: N export was generally higher when the rate was slow because more N could accumulate in hotspots over dry periods, and then be flushed more rapidly to streams at the onset of rain. In a case study, we found that when hotspots were modeled explicitly, peak streamflow nitrate export increased by 29%, enabling us to better capture the timing and magnitude of N losses observed in the field. N export further increased in response to interannual precipitation variability, particularly when multiple dry years were followed by a wet year. This modeling framework can improve projections of N export in watersheds where hotspots play an increasingly important role in water quality. Key Points: We developed a model framework to represent biogeochemical hotspots in dryland ecosystemsNitrogen export was sensitive to parameters controlling hotspot abundance, subsurface hydrologic connectivity, and soil moisture dynamicsThe abundance and physical characteristics of hotspots can affect the timing of hot moments [ABSTRACT FROM AUTHOR]

Wood vinegar (WV) is known to retard the release of ammonium (NH4+) from urea by inhibiting urea hydrolysis. However, the effect of WV on nitrogen leaching in soil is not known, and there are few studies on the effect of WV on microbial activity although WV exhibits antibacterial properties against pathogens in agriculture. Therefore, the purpose of this study was to investigate the effect of WV on controlling nitrogen leaching and soil microbial activity. Soils were treated with urea and WV, and the available inorganic nitrogen concentrations in the soil were compared with those from soils treated with N-(n-butyl)thiophosphoric triamide (NBPT), a commonly used urease inhibitor. The nitrate concentration in the soil was significantly decreased in the WV treatment, although the ammonium concentration was not affected by the WV treatment. Basal soil respiration was significantly increased in the WV and NBPT treatments although the microbial biomass was increased in the urea only treatment. The ammonium nitrogen concentration in the leachate was not significantly different in the WV and urea-treated soil compared to the urea-only treatment. However, the nitrate leaching increased in the soil treated only with urea at 16 days after the treatment although there was no statistically significant difference in the total leached nitrate. Therefore, WV can be used to reduce nitrogen leaching and enhance soil microbial activity. [ABSTRACT FROM AUTHOR]

Context. Overseer® is the primary software tool used to estimate farm-level nutrient cycle and management for regulatory purposes in New Zealand. The model compares feed demand among different livestock by using 'revised stock units' (RSUs, the annual energy requirement of a mature ewe to raise a single lamb to weaning; 6000MJ metabolisable energy). The RSUs for several common equine stock classes are not yet available, while those currently available within the model are based on the linear scaling of feed demand to liveweight, which does not consider allometric scaling of metabolism to liveweight or the differences in digestive physiology and nutrient metabolism between ruminants and monogastric hindgut fermenters (horses). Aim. To compare the current RSU values used in Overseer® for different equine stock classes, with the equineRSU values calculated using equine-specific models. Methods. Weighted average estimates of the bodyweight for the different equine livestock classes were calculated from the published literature. These weighted average estimates of bodyweight were used to estimate the energy requirements on the basis of data published by National Research Council. The resulting dry-matter intake and N intake from the equineRSU values and the current RSU values in use within Overseer® were modelled using published data on diet composition, crude protein content and the digestibility of the different feeds offered. Results. The current RSUs in Overseer were 2.5-6.8 units higher than the equineRSU values obtained from the equine-specific models. This overestimation in feed demand resulted in N-intake estimates at an animal level being 52-108% higher than values derived using the equine-specific estimates. Conclusion. The use of RSUs based on linear scaling of feed demand from ruminants on the basis of liveweight overestimates feed demand and N intake in horses. If horses are to be included within nutrient management models, feed demand must be based on published equine data for energy requirements to avoid over-inflation of N excretion. The equineRSUs calculated in this study reduce the risk of over-inflation of N intake and excretion, and subsequently the N leaching estimations. Implication. Failure to accurately model feed demand of horses within nutrient management software would unfairly compromise stocking density and horse management on large commercial breeding farms. The implication for these errors on economic impact and restricted livestock number is greatest for the Thoroughbred breeding industry due to the scale of the operations. [ABSTRACT FROM AUTHOR]

Global climate warming and increased climate variability may increase the number of annual freeze–thaw cycles (FTCs) in temperate zones. The occurrence of more frequent FTCs is predicted to influence soil carbon and nitrogen cycles and increase nitrogen leaching. Biochar has the potential to increase soil organic carbon storage and decrease nitrogen leaching. This study aims to investigate the impact of freeze–thaw cycles (FTCs) on soil nitrogen leaching in temperate zones, considering the potential exacerbation of FTCs due to global climate warming and increased climate variability. This study focuses on how biochar, a carbon-rich material produced from biomass, might mitigate nitrogen leaching by influencing soil characteristics. This study explores the interactions between different laboratory-simulated FTC frequencies (ranging from 0 to 12 cycles) and various biochar addition ratios (0%, 2%, 4%, and 6% w/w) on soil nitrogen leaching based on a total of 60 soil columns. Pearson correlations between the soil quality indicators and nitrogen leaching characteristics were detected, and partial least squares path modeling (PLS-PM) was used to assess the effects of the FTCs, biochar addition ratios, and soil quality indicators on the nitrogen leaching content. The results showed that the amount of leached soil NH4+-N and NO3−-N reached 0.129–1.726 mg and 2.90–7.90 mg, respectively. NH4+-N and NO3−-N first increased and then decreased under the FTCs, with the highest values being observed after the 6th FTC. As the biochar addition ratio increased, the NH4+-N and NO3−-N contents decreased. Correlation analysis showed that the nitrogen leaching content was significantly related to the soil pH, soil organic matter (SOM), NH4+-N content, and microbial biomass carbon content (MBC) (p < 0.01). The results of the conceptual path model revealed that nitrogen leaching characteristics were significantly affected by the pH, SOM, soil nitrogen content, and biochar addition ratio. Our results suggest that biochar addition can help reduce nitrogen leaching in farmland soil in areas with black soil and seasonal freeze–thaw cycles. [ABSTRACT FROM AUTHOR]

Whole orchard recycling (WOR) is an emerging practice in perennial cropping systems and is an alternative to open or cogeneration burning. It is an orchard removal practice that incorporates large amounts of woody biomass back into the soil system. In this study, we utilized a soil hydrological model (HYDRUS-1D) to evaluate the seasonal effects of WOR on water movement and nitrogen (N) retention for a newly established almond orchard on a typical sandy loam soil in the Central Valley of California. Soil moisture and N content were monitored across the first five growing seasons from 2018 to 2022. The model was able to track seasonal moisture fluctuation nicely compared to observed data. Additionally, an increase in soil moisture was measured in the WOR treatments in surface soil (i.e., 0- to 15-cm depths) where biomass was incorporated, and N leaching was reduced when compared to the unamended control. Simulations suggest that with WOR, irrigation can be reduced by up to 20 % during the tree establishment stage with minimal effect on root water uptake. This reduction in applied water can increase farm water use efficiency and reduce operational expenses, e.g., cost of water and pumping. Likewise, the reduction in N leaching observed in both predicted results and laboratory analysis can further cut farm capital costs, e.g., fertilization, and lessen orchard environmental impacts. Overall, results from our simulation show a positive effect of WOR on soil ecosystem services and can potentially be a profitable strategy for orchard turnover. The results have important implications in reducing groundwater nitrate contamination in irrigated agriculture in the Central Valley of California and applicable to most parts of Southwestern United States.

Chinese yam production is thriving in Aomori Prefecture, a cold and snowy region in Japan. Recently, there has been an increasing risk of nitrogen leaching in Chinese-yam fields, which consist of sandy soil, due to localized torrential rain. The relationships between the type of fertilizer used for Chinese-yam cultivation, the amount of nitrogen (N) leaching, and the timing of leaching remain unknown. Therefore, this study aimed to fill this knowledge gap by investigating the effects of different fertilizers (fast-acting and/or slow-release fertilizer) and irrigation practices (conventional and/or excessive irrigation) in order to mitigate the detrimental impact of nitrogen leaching on groundwater quality. An enhanced mathematical model and the spatiotemporal dynamics of inorganic nitrogen concentration in soil pore water were evaluated the negative impact of nitrogen leaching on the groundwater environment was evaluated. The results showed that the combined use of slow-release fertilizers could significantly reduce nitrate-nitrogen concentration in soil-water, especially during the harvest season. This study demonstrated that cultivating Chinese yam with a fertilizer application system that includes the use of slow-release fertilizer can diminish the negative impact of nitrogen leaching on the groundwater environment, contributing to our understanding of sustainable agricultural practices in regions facing similar environmental challenges. Therefore, our findings represent an important advancement providing new approaches to maintaining productivity while mitigating the adverse impacts on groundwater environments, as well as offering guidelines for agricultural practices in regions facing similar environmental challenges.

Abstract Atmospheric nitrogen (N) deposition and climate change are transforming the way N moves through dryland watersheds. For example, N deposition is increasing N export to streams, which may be exacerbated by changes in the magnitude, timing, and intensity of precipitation (i.e., the precipitation regime). While deposition can control the amount of N entering a watershed, the precipitation regime influences rates of internal cycling; when and where soil N, plant roots, and microbes are hydrologically coupled via diffusion; how quickly plants and microbes assimilate N; and rates of denitrification, runoff, and leaching. We used the ecohydrological model RHESSys to investigate (a) how N dynamics differ between N‐limited and N‐saturated conditions in a dryland watershed, and (b) how total precipitation and its intra‐annual intermittency (i.e., the time between storms in a year), interannual intermittency (i.e., the duration of dry months across multiple years), and interannual variability (i.e., variance in the amount of precipitation among years) modify N dynamics and export. Streamflow nitrate (NO3−) export was more sensitive to increasing rainfall intermittency (both intra‐annual and interannual) and variability in N‐limited than in N‐saturated model scenarios, particularly when total precipitation was lower—the opposite was true for denitrification which is more sensitive in N‐saturated than N‐limited scenarios. N export and denitrification increased or decreased more with increasing interannual intermittency than with other changes in precipitation amount. This suggests that under future climate change, prolonged droughts that are followed by more intense storms may pose a major threat to water quality in dryland watersheds.

ABSTRACT Widespread use of soluble mineral fertilizers derived from non-renewable sources has raised concerns about environmental impacts, energy expenditures, and sustainability. Combining biosolid and mineral sources of phosphorus and potassium to produce organomineral fertilizers (OMF) can be used as an alternative nutrient source while reducing the environmental impact of sewage residues. As this approach simultaneously provides nutrients and incorporates organic matter, we hypothesized the presence of an organic source (biosolid) granulated with mineral sources of potassium (K) and phosphorus (P) would reduce leaching due to the benefits of the organic source and the slower release caused by granulation. Our goal was to evaluate the effect of different OMFs on the leaching losses of nutrients. Two forms of isolated N, P, and K sources (granulated and non-granulated), five OMFs with different NPK proportions (1-2-0, 1-4-0, 1-0-2, 1-2-2, 1-2-4), and a control (unfertilized) were evaluated over ten weeks in a leaching column experiment. Non-granulated potassium sulfate exhibited the highest K leaching and did not differ from OMFs with K in their formulation (granulated PS, 1-0-2, 1-2-2, and 1-4-2). Planned contrasts showed that granulation was particularly effective at reducing K leaching, resulting in a 70 % reduction compared to non-granulated PS. While formulation and granulation showed a trend of potential benefits in reducing N-(NO3- + NO2-) leaching, the effect was not statistically significant. Interaction between fertilizer treatments and leaching events was marginally significant for NH4+ leaching, indicating temporal variations of OMFs in nutrient dynamics may be influenced by mineralization. As granulation modulated how OMFs affected nutrient leaching dynamics, this highlights the importance of the physical characteristics of fertilizers for effective nutrient management.

In order to address the increasingly prominent issues of water resource protection and agricultural non-point source pollution in the Erhai Lake Basin, this study conducted a two-year field experiment in Gusheng Village, located in the Erhai Lake Basin. In 2022, two irrigation treatments were set up: conventional flooding irrigation (CK) and controlled irrigation (C), with three replicates for each treatment. In 2023, aiming to enhance the utilization rate of rainwater resources and reduce the direct discharge of dry-farming tailwater from upstream into Erhai Lake. The paddy field was used as an ecological storage basin, and the water storage depth of the paddy field was increased compared to the depth of 2022. Combined with the deep storage of rainwater, the dry-farming tailwater was recharged into the paddy field to reduce the drainage. In 2023, two water treatments, flooding irrigation with deep storage and controlled drainage (CKCD) and water-saving irrigation with deep storage and controlled drainage (CCD) were set up, and each treatment was set up with three replicates. The growth and physiological index of rice at various stages were observed. Nitrogen leaching of paddy field in surface water, soil water, and groundwater under different water treatments after tillering fertilizer were observed. The research results show that the combined application of organic and inorganic fertilizers under organic planting can provide more reasonable nutrient supply for rice, promote dry matter accumulation and other indices, and also reduce the concentration of NH4+-N in surface water. Compared with CK, the yield, 1000-grain weight, root-to-shoot ratio, and leaf area index of C are increased by 4.8%, 4.1%, 20.9%, and 9.7%, respectively. Compared with CKCD, the yield, 1000-grain weight, root-to-shoot ratio, and leaf area index of CCD are increased by 6.5%, 3.8%, 19.6%, and 21.9%, respectively. The yield in 2023 is 19% higher than that in 2022. Treatment C can increase the growth indicators and reduce the net photosynthetic rate to a certain extent, while CCD rain-flood storage can alleviate the inhibition of low irrigation lower limit on the net photosynthetic rate of rice. Both C and CCD can reduce nitrogen loss and irrigation amount in paddy fields. CCD can reduce the tailwater in the Gusheng area of the Erhai Lake Basin to Erhai Lake, and also can make full use of N, P, and other nutrients in the tailwater to promote the formation and development of rice. In conclusion, the paddy field rain-flood storage methodology in the Erhai Lake Basin can promote various growth and physiological indicators of rice, improve water resource utilization efficiency, reduce direct discharge of tailwater into Erhai Lake, and decrease the risk of agricultural non-point source pollution.

Dairy slurry could be a significant source of nitrogen (N) for plants, but mismanagement can lead to atmospheric ammonia losses or nitrate leaching into groundwater. To make the use of dairy slurry efficient and reasonable, the loss of N pollution to the environment should be reduced. We used repacked lysimeters to comprehensively determine ammonia emission and N leaching losses in an alfalfa–soil system. The application of dairy slurry had no significant effect on alfalfa yield at the same rate of N application in comparison to chemical fertilizer, and adding humic acids significantly increased yield by about 12%. However, the application of dairy slurry increased the ammonia emission rate significantly, leading to an increase in the cumulative amount of ammonia emission, while the addition of humic acids reduced the ammonia emissions by 11%. Chemical fertilizer and dairy slurry application significantly increased nitrate leaching compared to the control treatment, while the addition of humic acids can significantly reduce ammonium N leaching. Dairy slurry was proven to be as effective as chemical N fertilizer in achieving the optimum biomass, and adding humic acids can significantly reduce N loss to the atmosphere and groundwater. This study showed the possibility of replacing chemical fertilizer with dairy slurry in alfalfa production and the advantages of humic acids’ addition to alfalfa to maintain production yield and improve environmental friendliness.

Excessive nitrogen (N) application in wheat-maize cropping systems was adjusted towards more sustainable practices to reduce hydrological N losses while maintaining crop yield. In comprehensive quantification of N management effects on crop yield, N use efficiency (NUE), hydrological N losses, and soil nitrate residual across eight seasons, we have added to growing evidence of strategies beneficial for sustainable crop production with lower hydrological N losses. The results show that adjusted N practices enhanced crop yield and NUE, as compared to farmer's practices, but benefits varied with N rates and types. Optimized N treatment (OPT, 180 kg N ha-1 in both maize and wheat seasons) with or without straw returning produced the most crop yield. They increased maize yield by 5.5% and 7.3% and wheat yield by 6.2% and 3.2% on average, as compared to farmer's practice with huge N application (FP, 345 kg N ha-1 and 240 kg N ha-1 in maize and wheat). Regulation of N release through amendment with controlled release urea at a rate of 144 kg N ha-1 crop-1 (CRU treatment) obtained 4.4% greater maize yield than FP, and sustained a similar wheat yield with less N input, resulting in the highest crop NUE. Additionally, CRU was most effective in mitigating hydrological N loss, with 39.5% and 45.5% less leachate N and 31.9% and 35.9% less runoff N loss than FP in maize and wheat seasons. Synthetic N input correlated significantly and positively with runoff and leachate N losses, indicating it was one of the dominant factors driving hydrological N losses. Moreover, compared to OPT, additional straw returning (STR) or substituting 20% of the nutrients by duck manure (DMS) further reduced runoff N discharges due to the fact that organic matter incorporation increased resilience to rainfall. N over-application in FP caused considerable nitrate accumulation in the 0-90-cm soil profile, while the adjusted N practices, i.e., OPT, STR, CRU, and DMS treatments effectively controlled it to a range of 79.6-92.9 kg N h-1. This study suggests that efforts using optimized N treatment integrated with CRU or straw returning should be encouraged for sustainable crop production in this region. [ABSTRACT FROM AUTHOR]

Conservation tillage and deep-side fertilization both hold the potential to reduce nitrogen leaching and improve grain yield and nitrogen use efficiency in fragrant rice cultivation practices. However, the combined impact of different tillage practices with deep-side fertilization on nitrogen leaching remains uncertain. Therefore, this study conducted on-site experiments for four rice-growing seasons in both early and late seasons in 2018 and 2019 using the fragrant rice varieties "Meixiangzhan 2" (MX) and "Xiangyaxiangzhan" (XY). The four experimental treatments included the following: conventional tillage with regular fertilization (T1), conventional tillage with simultaneous deep fertilization (T2), reduced tillage with simultaneous deep fertilization (T3), and no-tillage with simultaneous deep fertilization (T4). Our results indicate that the T4 treatment exhibited higher nitrogen leaching rates and potential nitrogen losses throughout the entire rice growth cycle, with a 4.51% increase in total mineral nitrogen leaching (TMNL) and a 1.86% increase in potential nitrogen leaching compared to T1 treatment. In contrast, the T2 treatment demonstrated the lowest nitrogen leaching rate, resulting in a 6.01% reduction in TMNL and a 9.57% decrease in potential nitrogen leaching compared to T1, demonstrating the most optimal performance. It is important to note that a reduction in nitrogen leaching does not directly translate into an increase in rice yield. Our study involved the cultivation of two fragrant rice varieties, 'Meixiangzhan2' (MX) and 'Xiangyaxiangzhan' (XY), and the results revealed some interesting insights. For MX, the T1 treatment resulted in lower daily grain outputs compared to the other treatments, with disparities ranging from 5.35% to 9.94%. Similarly, for XY, the T1 treatment yielded significantly lower daily grain outputs compared to the other treatments, with discrepancies ranging from 6.26% to 10.81% during the late season of 2019. Therefore, this study suggests that conventional tillage combined with deep fertilizer application can be considered as an effective agricultural strategy to reduce nitrogen leaching and enhance fragrant rice yields. [ABSTRACT FROM AUTHOR]

The nitrogen leaching of agricultural non-point source pollution is the key factor of eutrophication pollution in plateau lakes, and it is important to study the seasonal nitrogen leaching in growing region to alleviate the nitrogen contamination of agricultural non-point source pollution to groundwater and surface water in plateau lake deposit areas. In this study, the nitrogen leaching characteristics of a new type of water-soluble nitrogen fertilizer (calcium nitrate ammonium) and traditional urea under different fertilization and rainfall conditions were studied through indoor column experiments. The results indicate that during the fertilization period, the new nitrogen fertilizer (T1) releases more NO3--N, but its cumulative emissions of NH4+-N and TN are much smaller than urea (T2). Seasonal precipitation has a certain impact on T1 nitrogen leaching, The total nitrogen content lost during fertilization and rainfall simulation periods accounts for 76.60% and 81.97% of the total nitrogen application in rainy seasons and the dry season, respectively. However, it has a significant impact on T2 nitrogen leaching, with leaching rates of 93.18% and 87.95%, respectively. In the rainy season with strong and frequent rainfall in Erhai Lake, the replacement of traditional urea by new nitrogen fertilizer will have a certain mitigation effect on agricultural non-point source pollution, and the denitrification in lake sediments has a retention effect on nitrogen in the shallow vadose zone. This study has certain guiding significance for the timing and methods of agricultural planting and fertilization in the lake deposit areas around plateau lakes. [ABSTRACT FROM AUTHOR]

Biochar has been widely recommended as an effective soil amendment for reducing nitrous oxide (N2O) emissions and nitrogen (N) leaching. However, the effects of biochar application to Lei bamboo plantations on soil N2O emissions and N leaching remain unclear. These effects on soil N2O emissions and N leaching were investigated in the present study using five treatments applied with the same amount of N: rice husk at 10 t ha−1 (10H) and 30 t ha−1 (30H), biochar at 10 t ha−1 (10B) and 30 t ha−1 (30B), and no additions (control, CK). Both the 10H and 30H treatments significantly increased cumulative N2O emissions compared to the CK treatment, with an increment of 0.78 and 2.20 kg N ha−1, respectively. The 30B treatment significantly reduced cumulative N2O emissions by 0.90 kg N ha−1, whereas the 10B treatment had no significant effect. The reduction in N2O emissions following the high-rate biochar addition was probably due to the increased pH and the total abundance of nosZ I and nosZ II genes. The 30H treatment significantly increased nitrate N (NO3−–N) and dissolved organic N (DON) leaching by 38% and 170% respectively compared to the CK treatment, and had the largest N loss via N2O emissions and N leaching, while the 30B treatment had the lowest N loss. Partial least squares path modeling revealed that soil chemical properties [ammonium nitrogen (NH4+–N), NO3−–N, DON, dissolved organic C (DOC), total N (TN), soil organic C (SOC), and pH] dominantly affected soil N2O emissions, while the total abundance of denitrifying genes (nirS, nirK, nosZ I, and nosZ II) were the key factors involved in reducing NO3−–N leaching. There was a strong positive correlation between cumulative N2O emissions and N leaching loss, which may be related to excessive N surplus in the soil. Our results suggest that the replacement of rice husk by its biochar at a high-rate would reduce the risk of N2O emissions and N leaching loss effectively from Lei bamboo forests in subtropical China. [ABSTRACT FROM AUTHOR]

The present study aimed to assess the efficiency of monoammonium phosphate (MAP), with controlled-release technology, on cowpea, soybean, and corn in the Brazilian Eastern Amazon edaphoclimatic conditions. It were evaluated MAP conventional, FH Humics MAP that incorporates humic acid, and Potenza MAP that incorporates polymer, and two soils with different clay contents (23.1 and 37.6%), on the growth of cowpea, soybean, and corn, in a greenhouse. Simultaneously, it were evaluated four levels of P (0, 40, 80, and 120 kg ha-1 of P2O5), for the mentioned formulations on cowpea grain yield, in cerrado, and upland forest environments. Fertilization with MAP Humics and MAP Potenza promotes similar soybean, cowpea, and corn growth, and cowpea grain yield compared to conventional MAP, under greenhouse and field conditions, respectively. MAP formulations promote greater soybean, cowpea, and corn growth, and cowpea grain yield in the sandy loam and cerrado than in sandy clay soil and upland forest environment, respectively. Increasing levels of MAP formulations have no effect on cowpea grain yield in the cerrado but promote linear cowpea grain yield increase in the upland forest environment. [ABSTRACT FROM AUTHOR]

The mineralization of urea fertilizer significantly impacts nitrogen movement in the soil. An incubation study was done on a lab scale basis to examine nitrogen dynamics in soil inoculated with plant growth-promoting bacteria (PGPB) supplemented with varying levels of nitrogen fertilizer in the form of urea (0% N, 25% N, 50% N, 75% N, and 100% N). In the present experiment, sandy clay loam soil was used and incubated for four weeks, and the concentrations of NH4+¯N and NO3-¯N were monitored using the destructive method (Kjeldahl) to determine the mineralization rate of urea. Results showed higher NH4+¯N (11.880 mg/kg mineralized with UPMRB9N50 treatment) and NO3-¯N (20.060 mg/kg mineralized with UPMRB9N50 treatment) concentrations in the bacteriatreated soil compared to the uninoculated control. Urea-N remains higher (0.0353% and 0.0253% from UPMRB9N50 treatment in the first and second weeks, respectively) in bacteria-treated soil during the first two weeks, then gradually becomes zero towards the end of the observing period. Nitrogen (N) leaching loss was lower in bacterial inoculated soil compared to the control, and the leaching loss of N was greater with the increased N fertilizer rates. Cumulative N leaching loss is higher (29.797 mg/kg) in 100% N-treated soil than in other treatments. The findings observed that the beneficial bacteria could enhance the N mineralization to make the nutrient available for the crop while, at the same time, reducing leaching losses of fertilizer when supplied with a minimum amount of chemical fertilizer, thereby saving the input cost and protecting the environment. [ABSTRACT FROM AUTHOR]

Elevated anthropogenic nitrogen (N) input to headwater forests over the years increases soil N leaching and is expected to result in negative consequences like eutrophication of downstream regions. However, the long‐term response of N leaching to elevated N input in alpine forests remains elusive. Here, we explored the long‐term effects of the addition of N, as 15N‐labeled ammonium nitrate (15NH415NO3), on N leaching in a three‐N‐level experiment via a frequent sampling of soil leachates from two soil layers for eight years. The results showed that N addition increased the total dissolved N (TDN) concentrations and fluxes in leachates from the organic layer only for the high N addition (4 g N/m2/yr) treatment. Regardless of N treatment, dissolved organic N was the main leaching form of N. The effect of N addition on N leaching attenuated over time and it was partly attributed to the gradual increase in N retention by the aggrading forest. Overall, our data illustrate that N leaching showed declined trends over time due to the increased plants uptake, suggesting the important role of aggrading alpine forests in regulation of N leaching under elevated N deposition. Plain Language Summary: Atmospheric reactive nitrogen (N) deposition due to human activities has increased in ecosystems worldwide. N leaching from soil caused by N deposition has adverse effects on aquatic ecosystems as it induces water eutrophication and acidification. However, the long‐term response of N leaching to elevated N input in alpine forests remains elusive. Based on an 8‐year N addition experiment in an aggrading alpine forest, we found that long‐term N addition could significantly increase total dissolved N (TDN) leaching in the organic layer but not in the mineral layer. However, the magnitude of the N addition effect on TDN leaching decreased over time; this trend is partly regulated by the robust N uptake of the aggrading alpine forest. These results highlight the vital role of growing alpine forests in regulating the effect of N addition on N leaching. The alpine forest shows higher resistance under high N deposition with respect to future scenario. Key Points: Nitrogen addition increased total dissolved nitrogen leaching, mainly by enhancing dissolved organic nitrogen leachingThe effect of nitrogen addition on total dissolved nitrogen leaching decreased over timeIncreased nitrogen retention by the forest alleviated the adverse effect of nitrogen addition [ABSTRACT FROM AUTHOR]

Soil pH is important for influencing soil properties. High input of nitrogen (N) fertilizers and irrigation water has accelerated the soil acidification in plastic-shed greenhouses. However, little is known about the dynamics of soil pH buffering system, especially the base cations, and its response mechanisms under different N management practices. In this study, we investigated the responses of soil Ca2+ and Mg2+ leaching loss to nitrate leaching under different N application rate, N forms, or straw addition. Our long-term experiment in typical greenhouses showed that N application significantly decreased soil pH and increased Ca2+ and Mg2+ leaching loss by 43.1–73.6%, which correlated significantly and positively with nitrate leaching loss. However, optimizing N application and straw incorporation alleviated the leaching loss of Ca2+ and Mg2+ not only by alleviating the accompanying nitrate leaching caused by reduced N input, but also by reducing the conversion of exchangeable Ca2+ and Mg2+ to water-soluble Ca2+ and Mg2+ caused by alleviating soil pH reduction. The laboratory microcosm experiment showed that nitrate application did not reduce soil pH, but significantly increased the leaching loss of Ca2+ and Mg2+. Ammonium sulfate application also significantly increased the leaching loss of Ca2+ and Mg2+, whereas the effects were significantly reversed by nitrification inhibitors. These results further supported the importance of nitrate leaching in promoting the Ca2+ and Mg2+ losses. Together, this study revealed new insights into the dynamics of cation losses mainly regulated by nitrate leaching loss, highlighting that optimizing N management is an effective strategy to alleviate base cation losses and subsequent soil acidification for sustainable agricultural management.

IntroductionDespite various efforts to reduce nitrogen leaching from agricultural land, the permissible nitrate concentrations in groundwater have often been exceeded in the past. Intensive farming is often seen as the cause of the deterioration in water quality. Therefore, the present lysimeter study aimed to quantify nitrogen (N) leaching at different N fertilization levels for the agricultural land use systems of arable land and grassland to derive suitable management measures for improving groundwater quality.MethodsThe effects of three different of mineral fertilization treatments (50%, 100%, and 150%) in arable land and grassland use on four distinct soil types (loamy sand, sand, loam, loess) concerning seepage formation, nitrogen concentrations, nitrogen loads, dry matter yields and nitrogen balances were tested. The study was conducted at the lysimeter facility of the Helmholtz Centre of Environmental Research – UFZ at Falkenberg (northeast Germany). Twenty-four non-weighable lysimeters with a surface area of 1 m² and a depth of 1.25 m were managed as grassland and arable land with three different fertilization treatments since 1985.Results and DiscussionFor arable land use, N leaching differed between the studied soil types, with the highest N loads from the sand (36.6 kg ha–1 yr–1 ) and loamy sand (30.7 kg ha–1 yr–1 ) and the lowest N loads from loess (12.1 kg ha–1 yr–1) and loam soil (13.1 kg ha–1 yr–1). In contrast to grassland use, a reduction of N fertilization level by 50 % did not result in reduced N leaching for arable land, whereas a maximal 29% reduced dry matter yields was observed. An increase of N fertilization by 50 % did not cause significant enhanced N leaching at arable land use. Soil-and management-related factors (soil type, texture, soil tillage, crop rotation, and others) mask the effect of increased N fertilization rates in arable land using lysimeters. For arable land use, a reduction of N fertilizer levels as the only measure was insufficient to reduce NO3– leaching, and other strategies besides N fertilization levels are required to improve groundwater quality. Measures should be targeted to reduce N losses by mineralization processes.

Nitrogen (N) fertilizer recommendations for corn (Zea mays L.) in the US Midwest have been a puzzle for several decades, without agreement among stakeholders for which methodology is the best to balance environmental and economic outcomes. Part of the reason is the lack of long-term data of crop responses to N over multiple fields since trial data is often limited in the number of soils and years it can explore. To overcome this limitation, we designed an analytical platform based on crop simulations run over millions of farming scenarios over extensive geographies. The database was calibrated and validated using data from more than four hundred trials in the region. This dataset can have an important role for research and education in N management, machine leaching, and environmental policy analysis. The calibration and validation procedure provides a framework for future gridded crop model studies. We describe dataset characteristics and provide thorough descriptions of the model setup.

Abstract Organic amendments, such as compost and biochar, mitigate the environmental burdens associated with wasting organic resources and close nutrient loops by capturing, transforming, and resupplying nutrients to soils. While compost or biochar application to soil can enhance an agroecosystem's capacity to store carbon and produce food, there have been few field studies investigating the agroecological impacts of amending soil with biochar co‐compost, produced through the composting of nitrogen‐rich organic material, such as manure, with carbon‐rich biochar. Here, we examine the impact of biochar co‐compost on soil properties and processes by conducting a field study in which we compare the environmental and agronomic impacts associated with the amendment of either dairy manure co‐composted with biochar, dairy manure compost, or biochar to soils in a winter wheat cropping system. Organic amendments were applied at equivalent C rates (8 Mg C ha−1). We found that all three treatments significantly increased soil water holding capacity and total plant biomass relative to the no‐amendment control. Soils amended with biochar or biochar co‐compost resulted in significantly less greenhouse gas emissions than the compost or control soils. Biochar co‐compost also resulted in a significant reduction in nutrient leaching relative to the application of biochar alone or compost alone. Our results suggest that biochar co‐composting could optimize organic resource recycling for climate change mitigation and agricultural productivity while minimizing nutrient losses from agroecosystems.

Alterations in aboveground plant litter inputs due to global climate change can strongly change soil nitrogen (N) cycling, which will influence soil processes and functions. However, a comprehensive evaluation for the effects of altered litter inputs on soil N cycling is not available. We evaluated these effects using a global meta-analysis based on 1829 observations from 119 studies across different ecosystems including forests, shrublands and grasslands. Results showed that litter addition significantly increased soil N pools including total N (TN), dissolved organic N (DON), ammonium (NH4+), nitrate (NO3–) and microbial biomass N (MBN) by 4–––24 %, while litter removal decreased them by 10–––42 %. High initial soil TN pool weakened the positive effect of litter addition on soil TN. Moreover, litter addition significantly increased soil net N mineralization (+19 %), DON leaching (+56 %) and nitrous oxide (N2O) emission (+27 %), whereas litter removal reduced net N mineralization (-10 %) and increased NO3– leaching (+51 %). The response of soil net N mineralization to litter addition was stronger in broadleaved forests than that in coniferous forests, and negatively correlated with mean annual temperature and precipitation. The responses of soil TN, NH4+, NO3–, MBN and N2O emission to litter manipulation increased with increasing litter input rates. Therefore, altered litter inputs had strong effects on soil N cycling and these effects were regulated by soil N status, ecosystems, climates and experimental conditions. Our results provide insights into understanding how altered plant litter input affects soil N cycling and help better assess the soil processes under global climate change.

Balancing the nitrogen (N) budgets of agricultural production is crucial to maintaining yield and reducing the environmental pollution, especially in vegetable systems. Here, a systematic study was conducted on eggplant (Solanum melongena L.) yield, N uptake, N leaching and N balance in response to regular fertilization and irrigation (WF), reducing 20% of chemical fertilizers (W + 80%F), reducing 20% of irrigation amount (80%W+F), and biochar addition (WF+B) in a greenhouse eggplant system in Northeastern China. The results showed that compared with WF, 80%W+F treatment decreased eggplant yield, N uptake and N leaching by 11%, 23% and 14%, respectively. However, it increased N surplus by 30%. W + 80%F not only decreased N surplus by 4% and improved N balance, but also maintained eggplant yield and N uptake. WF+B significantly increased eggplant yield and N uptake, however, it sharply increased N surplus by 141% and caused N imbalance. Therefore, these results demonstrated that reducing chemical fertilizers by 20% would be the most suitable management practice for maintaining eggplant yield and reducing N surplus in greenhouse vegetable systems. [ABSTRACT FROM AUTHOR]

This study aims to examine the impact of combined irrigation and fertilizer control on the summer maize yield, nitrogen use efficiency (NE), and nitrogen leaching (NL) in the Yellow River Basin. Based on the measured data from the field summer maize experiment in 2021 and 2022, a water-nitrogen movement model was constructed for 'Zhengdan 958' maize under two irrigation methods (wide furrow irrigation (G) and border irrigation (Q)), three fertilizer rates (120 kg/ha (N1), 220 kg/ha (N2), and 320 kg/ha (N3)), and three fertilizer frequencies (1 (T1), 2 (T2), and 3 (T3)), yielding 18 total treatments. Calculation of nitrogen leaching was based on water nitrogen transport modeling. The study then analyzed the factors and their combined effects. A multi-objective optimization genetic algorithm (NSGA-II) was established to evaluate maize yield, nitrogen use efficiency, and nitrogen leaching. The results indicate that the determination coefficients between simulated and measured water, nitrogen values exceeded 0.74. The rate optimized HYDRUS model effectively simulated the soil solute movement. The interaction of the irrigation method, fertilizer rate, and fertilizer application frequency did not significantly affect yield and nitrogen leaching, but did significantly impact nitrogen use efficiency (p < 0.05). Nitrogen leaching increased gradually as nitrogen application increased. The yield under wide furrow irrigation was 6.26% higher than that under border irrigation. The optimal coupling scheme of water and fertilizer was obtained using the genetic algorithm multi-objective optimization method, where the combined GN2T2 treatment was the optimal management model, the summer maize yield reached 14,077 kg/ha, nitrogen use efficiency and nitrogen leaching were reduced to 30.21 kg·kg−1 and 17.64 kg/ha, respectively. These findings can guide summer maize cultivation in the Yellow River Basin and assist in reducing nitrogen surface source pollution. [ABSTRACT FROM AUTHOR]

Nitrogen (N) losses by leaching are significant in terms of environmental contamination. Thus, attention has been given to urination points of ruminant urine because they contain high levels of N. Integrated crop-livestock systems (ICLS), in turn, seek to intensify production and, at the same time, make production systems more sustainable. Therefore, it is crucial to know the behavior of N to boost its cycling and, consequently, minimize its impacts (environmental and economic). The objective of this study was to evaluate N leaching from bovine urine in a mixed pasture of Lolium multiflorum x Avena strigosa in two different integrated systems, crop-livestock (CL) and crop-livestock with trees (CLT), and two N doses (90 and 180 kg N ha−1). During the winter 2018, the study was conducted in the Brazilian subtropics, in sandy texture soil. The application of higher doses of nitrogen fertilizer (180 kg N ha−1) causes an increase in the concentration of nitrogen excreted in urine and, consequently, increases nitrate and ammonium contents in the soil at the urine points. Higher nitrogen contents were observed at the urine points, since the uptake of nutrients by the forage plants was reduced due to shading of the plants, leading to a reduction in dry matter production of the pasture. The area of action/diffusion of urinary N does not exceed 25 cm from the center point of urination. No leaching of nitrate or ammonium was observed at the sampled urine points, up to a depth of 40 cm. However, the adoption of more intensified production systems (i.e., with the inclusion of grazing animals and increased nitrogen fertilization) should be conducted under conditions that provide high plant uptake of soil nutrients to reduce the risk of losses.

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Use of solid agricultural digestate as a substitute for chemical fertilizers in Mediterranean cropping systems can be a valuable approach to improving soil fertility. However, it is important to accurately assess its mineralisation dynamics in order to avoid uncontrolled nutrient releases in agroecosystems. With this aim, a field experiment was conducted to evaluate the effects of solid digestate application on total soil nitrogen (TSN), extractable organic N (EON) and mineral N forms (NH4+-N and NO3−-N) in two Mediterranean soil profiles (clay and sandy-loam) over one year. The solid digestate increased TSN and EON concentrations in the upper soil layer (0–20 cm) of both soils, more in the clay soil, with a decreasing effect in the lower soil layers (20–40 and 40–60 cm). The amendment increased NH4+-N concentrations, with a greater and longer-lasting effect in the clay soil, especially in the first two soil layers (0–20 and 20–40 cm), while in the lowest, it was limited at the first sampling epoch. The NO3−-N copied the NH4+-N trends in both soils, with a greater effect on the 0–20 cm soil layer at all sampling epochs. The present study suggests that solid digestate, applied at a dose of 30 Mg ha−1, can be a useful alternative to mineral N fertilisers for clay and sandy-loam soils in Mediterranean orchards. [ABSTRACT FROM AUTHOR]

The partial substitution of chemical nitrogen fertilizers with organic fertilizer and slow-release fertilizer could improve pineapple yield and nitrogen use efficiency (NUE) and decrease greenhouse gas (GHG) emissions. However, the effect of organic and slow-release fertilizer substitution strategies on the carbon footprint (CF), nitrogen footprint (NF) and net ecosystem economic benefits (NEEB) from pineapple fields in the tropics remains largely unclear. Therefore, we conducted a long-term pineapple field trial (2017–2021) for the first time with five fertilization strategies (CK: no fertilizer; F: conventional fertilization(nitrogen (N) 817 kg ha−1, phosphorus pentoxide (P2O5) 336 kg ha−1, potassium oxide (K2O) 945 kg ha−1); RF: reduction of 41.7% N, 72.0% P2O5 and 33.1% K2O on an F basis; RFO: replacement of 20% N input with organic fertilizer on an RF basis; RFOS: replacement of 15% N input with slow-release fertilizer on an RFO basis) to identify the pineapple fruit yield, NUE, CF, NF and NEEB in the tropics. The results showed that in comparison to the F treatment, the RF, RFO and RFOS treatments improved pineapple yield (7.6%, 12.4% and 26.3%, respectively), NUE (66.4%, 75.5% and 87.7%, respectively, p < 0.05) and partial factor productivity of nitrogen (PFPN) fertilizer (84.8%, 92.8% and 116.7%, respectively, p < 0.05). Additionally, of all the treatments, the RFOS treatment had the highest yield (87.8 t ha−1). N leaching (50.1–69.1%) and ammonia volatilization (21.6–26.2%) were the two primary routes for reactive nitrogen (Nr) loss. The field soils (36.8–45.7%) and N fertilizer production and transportation (21.2–29.5%) dominated the GHG emissions. Compared to the F treatment, the RF, RFO and RFOS treatments showed decreases in Nr losses, NF, GHG emissions and CF of 36.6–41.1%, 43.3–51.9%, 19.0–29.1% and 24.5–41.7%, respectively. Of all the treatments, the RFOS treatment had the lowest CF (191.8 kg CO2eq ha−1 season) and NF (1.9 kg N t−1 season). Additionally, the NEEB of the RF, RFO and RFOS treatments improved by 13.0–39.9% over that of the F treatment. The RFOS treatment (54,880 USD ha−1) resulted in the highest NEEB of all treatments. Therefore, the substitution of conventional inorganic fertilizers with organic and slow-release fertilizers is an effective method for achieving sustainable pineapple production. However, a process for further reducing GHG emissions from farmland soils and Nr losses from organic fertilizer addition still need attention in terms of pineapple production. [ABSTRACT FROM AUTHOR]

The overuse of fertilizers in open-field tomato leads to soil deterioration through nutrient leaching and increases the risk of agricultural non-point source contamination. Currently, the combined effects of different fertilization methods on soil nitrogen leaching and tomato production are still unclear. Therefore, the most effective fertilization method for open-field tomato should be discovered by examining how different fertilization methods affected tomato yield and quality, nitrogen use efficiency (NUE), and soil nitrogen leaching. Compared with CK (no fertilization), fertilization significantly increased the yield, total sugar (TS), total soluble solids (TSS), and vitamin C (vC) contents of fruits (p < 0.05), and OPT (optimal fertilization, controlled release nitrogen application, 240 kg ha−1) had the largest effect on increasing yield, quality, and net profit. However, when the fertilizer application rate reached 375 kg ha−1, these indices decreased. Nitrogen leaching concentrations, leaching amount, and titratable acids (TAs) increased with increased nitrogen application rates. Compared with other treatments, OPT reduced the total leaching amounts of total nitrogen (TN), nitrate nitrogen (NO3−-N), and ammonia nitrogen (NH4+-N) by 30.09–51.79%, 24.89–50.03%, and 30–65%, respectively. Principal component analysis (PCA) showed that OPT achieved the highest overall score in terms of yield, quality, and nitrogen leaching conditions. The partial least squares path modeling (PLS-PM) further reveals that applications of high amounts of nitorigen have a positive effect on soil nitrogen leaching. The amount of nitrogen leaching vegetatively affects tomato yield and quality, while plant uptake of nitrogen positively affects tomato production. These findings confirm the importance of using controlled-release fertilizers and reducing nitrogen inputs to control nitrogen leaching and enhance open-field tomato yields.

Global climate warming and increased climate variability may increase the number of annual freeze–thaw cycles (FTCs) in temperate zones. The occurrence of more frequent FTCs is predicted to influence soil carbon and nitrogen cycles and increase nitrogen leaching. Biochar has the potential to increase soil organic carbon storage and decrease nitrogen leaching. This study aims to investigate the impact of freeze–thaw cycles (FTCs) on soil nitrogen leaching in temperate zones, considering the potential exacerbation of FTCs due to global climate warming and increased climate variability. This study focuses on how biochar, a carbon-rich material produced from biomass, might mitigate nitrogen leaching by influencing soil characteristics. This study explores the interactions between different laboratory-simulated FTC frequencies (ranging from 0 to 12 cycles) and various biochar addition ratios (0%, 2%, 4%, and 6% w/w) on soil nitrogen leaching based on a total of 60 soil columns. Pearson correlations between the soil quality indicators and nitrogen leaching characteristics were detected, and partial least squares path modeling (PLS-PM) was used to assess the effects of the FTCs, biochar addition ratios, and soil quality indicators on the nitrogen leaching content. The results showed that the amount of leached soil NH4+-N and NO3−-N reached 0.129–1.726 mg and 2.90–7.90 mg, respectively. NH4+-N and NO3−-N first increased and then decreased under the FTCs, with the highest values being observed after the 6th FTC. As the biochar addition ratio increased, the NH4+-N and NO3−-N contents decreased. Correlation analysis showed that the nitrogen leaching content was significantly related to the soil pH, soil organic matter (SOM), NH4+-N content, and microbial biomass carbon content (MBC) (p < 0.01). The results of the conceptual path model revealed that nitrogen leaching characteristics were significantly affected by the pH, SOM, soil nitrogen content, and biochar addition ratio. Our results suggest that biochar addition can help reduce nitrogen leaching in farmland soil in areas with black soil and seasonal freeze–thaw cycles.

Cover crops (CCs) can improve soil nutrient retention and crop production while providing climate change mitigation co‐benefits. However, quantifying these ecosystem services across global agricultural lands remains inadequate. Here, we assess how the use of herbaceous CCs with and without biological nitrogen (N) fixation affects agricultural soil carbon stocks, N leaching, and crop yields, using the dynamic global vegetation model LPJ‐GUESS. The model performance is evaluated with observations from worldwide field trials and modeled output further compared against previously published large‐scale estimates. LPJ‐GUESS broadly captures the enhanced soil carbon, reduced N leaching, and yield changes that are observed in the field. Globally, we found that combining N‐fixing CCs with no‐tillage technique could potentially increase soil carbon levels by 7% (+0.32 Pg C yr−1 in global croplands) while reducing N leaching loss by 41% (−7.3 Tg N yr−1) compared with fallow controls after 36 years of simulation since 2015. This integrated practice is accompanied by a 2% of increase in total crop production (+37 million tonnes yr−1 including wheat, maize, rice, and soybean) in the last decade of the simulation. The identified effects of CCs on crop productivity vary widely among main crop types and N fertilizer applications, with small yield changes found in soybean systems and highly fertilized agricultural soils. Our results demonstrate the possibility of conservation agriculture when targeting long‐term environmental sustainability without compromising crop production in global croplands. Plain Language Summary: Increasing crop productivity while maintaining a healthy environment is a major challenge for global agriculture. Cover crops (CCs), mostly grown during the fallow period and plowed into in soils, are expected to improve soil fertility and crop yields while reducing chemical fertilizer use, but their overall impacts on global croplands remain unknown. This study investigates the long‐term influence of cover cropping on three ecosystem service indicators across four dominant farming systems (wheat, maize, rice, and soybean) using an ecological model. We find that adoption of CCs can enhance soil carbon stocks, which would contribute to slowing climate change, and benefit environments through reducing nitrogen pollution to water bodies. Among the modeled cover crop species, legumes show higher potential in increasing cash crop yields than non‐legumes, but the effect is highly dependent on the crop rotation, chemical fertilizer rate, and management duration. Our results highlight that proper implementation of legume CCs can support food security and environmental sustainability in global agricultural ecosystems. Key Points: Cover crops (CCs) can increase soil carbon sequestration by 0.11–0.15 Pg C per year while reducing N leaching by 34%–41% in global croplands compared with fallow managementThe influence of CCs on cash crop yields varies widely among crop rotations, climates, management duration, and N fertilizer applicationsLegume CCs in no‐tillage system is overall identified as a promising practice to achieve environmental sustainability without compromising crop production in agricultural ecosystems [ABSTRACT FROM AUTHOR]

Organic amendments, such as compost and biochar, mitigate the environmental burdens associated with wasting organic resources and close nutrient loops by capturing, transforming, and resupplying nutrients to soils. While compost or biochar application to soil can enhance an agroecosystem's capacity to store carbon and produce food, there have been few field studies investigating the agroecological impacts of amending soil with biochar co‐compost, produced through the composting of nitrogen‐rich organic material, such as manure, with carbon‐rich biochar. Here, we examine the impact of biochar co‐compost on soil properties and processes by conducting a field study in which we compare the environmental and agronomic impacts associated with the amendment of either dairy manure co‐composted with biochar, dairy manure compost, or biochar to soils in a winter wheat cropping system. Organic amendments were applied at equivalent C rates (8 Mg C ha−1). We found that all three treatments significantly increased soil water holding capacity and total plant biomass relative to the no‐amendment control. Soils amended with biochar or biochar co‐compost resulted in significantly less greenhouse gas emissions than the compost or control soils. Biochar co‐compost also resulted in a significant reduction in nutrient leaching relative to the application of biochar alone or compost alone. Our results suggest that biochar co‐composting could optimize organic resource recycling for climate change mitigation and agricultural productivity while minimizing nutrient losses from agroecosystems. [ABSTRACT FROM AUTHOR]