Query:  Chemical fertilizer pollution in China

title: Development Trend and Driving Factors of Agricultural Chemical Fertilizer Efficiency in China
abstract: In China, a high input of chemical fertilizers is currently required for a relatively low increase in agricultural production, and this has resulted in prominent nonpoint source pollution and problems related to the quality of agricultural products. These phenomena threaten China's implementation of United Nations Sustainable Development Goal 2 (SDG 2) To explore agricultural chemical fertilizer efficiency and the factors driving the growth in chemical fertilizer use in China, as based on an international comparative analysis of China's chemical fertilizer input, the development trend in the application level and the efficiency in the use of chemical fertilizer in China were subject to time series analysis, and the factors influencing change were identified and analyzed using the Logarithmic Mean Divisia Index (LMDI) The results show that: (1) The gap in agricultural chemical fertilizer efficiency is still large when comparing China with modern agricultural countries, and excessive fertilizer input is still a major problem. (2) The continuous growth in the total amount of chemical fertilizer applied in China during the past 18 years has contributed to the increase in chemical fertilizer application intensity, which provided a cumulative contribution of 85.52% with smaller contributions from the planting structure and crop sown area. Based on the analysis of fertilizer application, the chemical fertilizer application intensity of the main grain crops was the most significant factor, accounting for about a 40.00% cumulative contribution.  Of these, the reduction in application intensity was the most effective at reducing the overall amount of applied fertilizer. To meet the target for achieving sustainable agricultural development, China must still reduce its use of chemical fertilizers by at least 21.80 million tons. Based on the results of current measures and international experience, some suggestions for reducing fertilizer usage are provided.

title: Temporal and spatial pattern evolution and grouping prediction of non point source pollution of chemical fertilizers in China
abstract: Reducing pollution caused by chemical fertilizers while continuously increasing the output value of agriculture at the same time is an inevitable requirement to improve high quality development of agriculture. Actions aimed at achieving zero growth in 1080 Zhong Guo Sheng Tai Nong Ye Xue Bao (Zhong Ying  http:/www.ecoagri.ac.cn chemical fertilizer use have been formulated and implemented in provinces across China. However, inconsistencies in progress and effectiveness among provinces may affect each other. The fertilizer loss coefficient method was used to calculate the emission intensity of non point source pollution in 31 provinces across the Chinese mainland from 1997 to 2018. Spatial autocorrelation and hotspot analysis methods, based on the calculated emission intensity, were used to reveal the emission intensity temporal and spatial characteristics, and to analyze the interaction effect on neighboring provinces. According to these characteristics, the country was grouped into three regions: a hot spot region, a cold spot region, and a non hot (cold) spot region. Then, the Environmental Kuznets Curve (EKC) trend between the non point source pollution emission intensity of fertilizers and the per capita agricultural output value in each group was simulated and predicted under spatial heterogeneity and spatial correlation conditions. The results showed that the emission intensity varied considerably among provinces across the country. The emission intensity was spatially positively autocorrelated across the country with a cluster mode. A hot spot analysis showed that the spatiotemporal pattern for non point source pollution caused by fertilizers was relatively stable. The hot spot region was mainly concentrated in the central and southern parts of China, especially in the middle and lower reaches of the Yangtze River. However, in recent years, the number of hotspots in the Huanghuaihai region had significantly decreased. The cold spot region was mainly concentrated in the western region and Heilongjiang Province. The EKC trend simulation, based on temporal and spatial pattern feature grouping, showed that there was a significant nonlinear EKC relationship between agricultural economic growth and chemical fertilizer non point source pollution in each group. However, the trend and the inflection point of each curve were clearly different. The hot spot region appeared as an "inverted U type" curve, but both the cold spot region and the non hot (cold) spot region had "inverted N type" curves. Most provinces in each region were in the ascending phase of the curves. Industrial structure adjustment and industrial transfer promoted the spatial spillover effect of fertilizer derived non point source pollution among the regions. Therefore, coordinated governance among regions needs to be introduced. Based on the above results, we propose that there should be corresponding policy implications, and that suitable fertilization equipment should be developed and promoted to increase fertilizer utilization in the hot spot region. Conservation farming should be applied and the use of organic fertilizer promoted in the cold spot region. The non hot (cold) spot region should reasonably adjust the structure of its agricultural industry and focus on the crop livestock and poultry farming cycle. Ecological compensation and emissions trading should be implemented to achieve collaborative governance.

title: Runoff loss of nitrogen and phosphorus from a rice paddy field in the east of China: Effects of long term chemical N fertilizer and organic manure applications
abstract: Agrochemicals, e.g. nitrogen (N) and phosphorus (P) fertilizers are being used extensively to increase the agricultural production; however, considerable losses of these fertilizers find their way to the surrounding surface water bodies causing severe pollution and eutrophication. Such non point source of pollution seemed to be more pronounced in the rice fields. Accordingly, a two year (2018 2019) field study was conducted at a rice paddy field under long term N fertilizer management practices in the rural suburb of Shanghai, China. N and P losses through the surface runoff in the paddy field were measured. Six N fertilizer practices were performed since 2011 as follows: no N treatment (N0) chemical N treatment (urea, N 46% applied at the rates of 100 (N100) 200 (N200) 300 (N300) kg N ha 1 and combinations of chemical and organic N fertilizers (30% organic manure) at the rates of 200 (ON200) and 300 kg N ha 1 (ON300) Results showed that the highest runoff losses of TN (20.5 kg ha 1) and TP (1.66 kg ha 1) were respectively produced by N300 and ON300 practices during the rice growing season. TN runoff loss significantly decreased by reducing the rate of N fertilizer (P

title: Manure combined with chemical fertilizer increases rice productivity by improving soil health, post anthesis biomass yield, and nitrogen metabolism
abstract: Excessive reliance on chemical fertilizer (CF) in conventional farming is a serious concern owing to its negative effects on soil health, the environment, and crop productivity. Organic manure is an alternative source of fertilizer to reduce the amount of CF usage in agriculture, decrease environmental pollution, and ensure sustainable crop production. This study assessed the integrated effect of poultry manure (PM) and cattle manure (CM) with CF on soil properties, plant physiology, and rice grain yield. Additionally, the difference in pre and post anthesis dry matter (DM) and nitrogen (N) accumulation and their relationship with grain yield was also determined. Pot experiments were performed in the early and late growing season at the experimental station of Guangxi University, China, in 2018. A total of six treatments, i.e. T1 CF0; T2 100% CF; T3 60% CM 40% CF; T4 30% CM 70% CF; T5 60% PM 40% CF, and T6 30% PM 70% CF were used in this pot experiment. Results showed that T6 enhanced leaf photosynthetic efficiency by 11% and 16% chlorophyll content by 8% and 11% panicle number by 12% and 16% and grain yield by 11% and 15% in the early and late seasons, respectively, compared to T2. Similarly1, post anthesis N and DM accumulation, N uptake, and soil properties (i.e. soil organic carbon, total N, and bulk density) were improved with integrated CF and manure treatments over the sole CF treatments. Interestingly, increases in post anthesis N uptake and DM production were further supported by enhanced N metabolizing enzyme activities (i.e. nitrate reductase, glutamine synthetase, and glutamate oxoglutarate aminotransferase during the grain filling period in combined treatments. In addition, the linear regression analysis showed that post anthesis DM (R2 0.95) and N (R2 0.96) accumulation were highly associated with grain yield of rice. Thus, the combination of 30% N from PM or CM with 70% N from CF (i.e. urea) is a promising option for improvement of soil quality and rice grain yield. Furthermore, our study provides a sustainable nutrient management plan to increase rice yield with high N use efficiency.

title: Emergy evaluation and economic analysis of compound fertilizer production: A case study from China
abstract: The compound fertilizer market has an increasing share in the Chinese chemical fertilizer consumption. However, this industry is challenged by the increasing use of nonrenewable resources and pollution emissions. Therefore, promoting the sustainability of this industry is urgent. This study proposes a combination of improved emergy analysis methods and an economic evaluation to comprehensively assess the compound fertilizer production. The proposed methods quantify the adverse effects of pollution emissions and the effect of one subsystem on the integrated system. A case study was conducted on a compound fertilizer enterprise in the Jiangxi Province of China and the following conclusions were drawn: 97.82% of the emergy input to the system comes from the nonrenewable resources (especially urea and ammonium dihydrogen phosphate) the ecological services and emergy loss derived from pollution discharge, mainly from HCl gas and dust emissions, reach 7.68E+17 sej/yr and 5.76E+17 sej/yr, respectively, which reduce the environmental sustainability level of the integrated system by 0.03% the improved emergy sustainability index values of the integrated system and its subsystems range between 0.0203 0.0228, which indicates their long term unsustainability; the nitro water soluble fertilizer subsystem has the largest adverse effect on the sustainability of the enterprise (0.24) the environmental contribution is far underestimated by 78 98% in the prices of the four kinds of fertilizers investigated in this study; the sulfur based fertilizer subsystem has the highest economic benefit (net economic benefit ratio 0.31) but the least environmental sustainability (improved emergy sustainability index 0.0203) among the four subsystems. Finally, this study proposes promoting green procurement of main raw materials, optimizing the existing processes, improving the environmental performance of the sulfur based fertilizer subsystem, and increasing the prices of compound fertilizers.

title: Developing a Sustainable Management Strategy for Quantitative Estimation of Optimum Nitrogen Fertilizer Recommendation Rates for Maize in Northeast China
abstract: Excessive application of chemical fertilizers has caused a series of environmental problems, including environmental pollution. Quantitative estimation of a sustainable fertilizer recommendation rate is paramount for formulating fertilizer management strategies to improve productivity of low yield regions and to prevent environmental damage. In this study, the database was drawn from 31 experimental sites in the main maize production region of Northeast China, during the period 2009 to 2013, to study the relationships between yield factors and nitrogen application rates, and to explore sustainable nitrogen (N) fertilizer recommendation rates based on analysis using the fertilizer response model. The fertilizer response model method is a technique that can provide effective performance predictions for the estimation of the optimum crop balanced fertilizer rates in varied agricultural regions. Results revealed that the average grain yield in treatment of N180 (the amount of nitrogen application rate was 90 kg ha 1) was highest, and the yield increase rate ranged from 4.77% to 58.53% with an average of 25.89% The sequence of grain yields in each treatment receiving N fertilizer management from high to low was: N180 N270 N90 in all the regions. The agronomic efficiency for applied N in N90, N180, N270 treatments was 11.8, 10.8, and 4.6 kg kg 1, respectively. The average optimum N fertilizer recommendation rate in Liaoning province was 180.4 kg ha 1, and the predicted optimum yield ranged between 7908.7 and 12,153.9 kg ha 1, with an average of 9699.1 kg ha 1. The mean optimum N fertilizer recommendation rate in western (WL) central and southern (SCL) eastern (EL) and northern (NL) of Liaoning province were 184.2, 177.2, 163.5, and 192.5 kg ha 1, and the average predicted optimum yields were 8785.3, 10,630.3, 9347, and 9942.4 kg ha 1. This study analyzed the spatial distribution of optimum fertilizer recommendation rates and the corresponding theoretical yield based on a large database, which helped to develop effective and environment friendly N management strategies for sustainable production systems.

title: Driving forces and future trends on total nitrogen loss of planting in China.
abstract: Nitrogen production is one of the major aspects of global change over the past century. Nowhere is this change more dramatic than in China. Understanding the variations and driving forces of nitrogen loss from planting is critical to the sustainable development of Chinese agriculture. Here we found total nitrogen (TN) loss of China showed an overall downward trend from 2007 to 2016, as a result of abatement strategies for China on "Soil Testing and Formula Fertilization" and "Reducing Fertilizer Application while Increase the Efficiency" based on the data of National Agricultural Pollution Survey. The results of structural equation model showed that the path coefficient of anthropogenic drivers and natural conditions on TN loss were 0.934 and 0.137 respectively, suggesting that anthropogenic drivers had greater effects on TN loss than natural conditions. In terms of anthropogenic drivers, fertilizer usage and consumption of chemical pesticides were the two major factors affecting TN loss with path coefficients of 0.958 and 0.946, respectively, which was mainly related to their over application. For natural conditions, relative humidity, water supply situation, and annual precipitation were found to be the dominant factors affecting TN loss, revealing that moist soils increased TN loss by enhancing ammonia volatilization, denitrification and nitrogen leaching. Forecasts for 2050, under two scenarios especially for the high TN loss scenario, the indication sifts that China will face a high risk of increasing TN loss from planting, suggesting that China's abatement strategies cannot be slackened. Here, the current status and future trends of China's nitrogen loss provide direction and pertinence to Chinese abatement strategies for nitrogen, effectively preventing and controlling agricultural non point source pollution.

title: Nitrogen and phosphorus runoff losses were influenced by chemical fertilization but not by pesticide application in a double rice cropping system in the subtropical hilly region of China.
abstract: As one of the important nitrogen (N) and phosphorus (P) pollution sources of waters, the paddy water N and P runoff losses are still poorly understood in the double rice cropping system under the interaction of chemical fertilizer and pesticide. In the subtropical hilly region of China, we conducted a 1.5 year continuous and high frequency monitoring of paddy water N and P concentrations, runoff N and P losses, and grain yield in a double rice cropping system with different chemical fertilizer and pesticide application rates. The results showed that the high risk periods for N loss were in the first 5 days after the base fertilizer (BF) application and the first 10 days after the topdressing fertilizer application in both early and late rice seasons, while the high risk periods for P loss were in the first 5 days after BF application in the early rice season and the first 15 days after BF application in the late rice season. The N and P runoff losses in the early rice season were greater than those in the late rice season, due to that the N and P fertilizers use efficiencies were lower, and thus paddy water N and P concentrations were higher in the early rice season. The paddy N and P concentrations and N and P runoff losses increased significantly with increased fertilizer application rates, while the pesticide application rate did not significantly affect N and P losses. Therefore, special effects (e.g. avoiding high irrigation, fertilizer deep application) should be taken during the high risk periods of N and P losses to reduce the N and P runoff losses in the double rice cropping system, especially in the early rice season. There are also potentials to reduce fertilizer and pesticide input without reducing rice grain yield for the double rice cropping system in the subtropical hilly region of China.

title: Groundwater Chemical Characteristics and Controlling Factors in a Region of Northern China with Intensive Human Activity
abstract: The identification of groundwater chemical characteristics and the controlling factors is of major concern in water environment studies. In this study, we identified the groundwater chemical characteristics, evolution laws and main control factors in a region severely affected by human activities using hydrochemical and multivariate statistical techniques. The results showed that the concentrations of NO3 and TH were the primary pollution factors in the region with intensive human activity because of high concentration and over the standard rates. The major types of groundwater chemistry were HCO3*SO4 Ca and HCO3*SO4 Ca*Mg. The sulfate type water was as high as 75.0% 69.2% and 41.2% in the three hydrogeological units. In addition, there were Cl type and Na type waters, indicating that the groundwater in this area has been significantly affected by human activities. A principal component analysis (PCA) indicated that the three factors affecting groundwater hydrochemistry in the study area are domestic sewage and fertilizer, water rock interactions and industrial wastewater. Therefore, we suggest that the government and water environment management departments should prevent the discharge of domestic and industrial wastewater without standardized treatment first in order to effectively prevent the further deterioration of groundwater quality in this area.

title: A comprehensive framework for assessing the impact of potential agricultural pollution on grain security and human health in economically developed areas
abstract: Agricultural pollution poses a considerable challenge to grain security and human health, especially in economically developed areas. Mineral exploitation, chemical enterprise operation, pesticide and fertilizer application, sewage discharge, and vehicle emissions are the pollution sources of agricultural land. Identifying and assessing potential agricultural pollution (PAP) is, therefore, the most urgent task to achieve grain security and the human health. Large scale (e.g. regional or national) PAP assessment can be very expensive, which could also generate a certain amount of information that usually discourages evaluation by decision makers. To identify areas for regional priority investigation, here we proposed an assessment framework for PAP in economically developed areas. The framework consisted of PAP assessment, vulnerability assessment, hazard assessment, and socio economic assessment. Then, we conducted a case study by using the proposed framework in one of China's economically developed areas, Zhejiang Province. The results showed that PAP, especially soil heavy metal pollution, soil acidification, and surface water pollution involved almost the entire study area. High vulnerability high hazard areas were mainly associated with high socio economic development or high grain yield. These areas had negatively affected grain security and increased carcinogenic risk, potentially contributing to the formation of cancer villages. Based on the results, we proposed measures for environmental risk managers to alleviate the impact of PAP on grain security and human health in economically developed areas.