Nitrogen Fertilizer Consumption Research Articles

Spatiotemporal characteristics and driving factors of chemical oxygen demand emissions in China’s wastewater: An analysis based on spatial autocorrelation and geodetector

The advancement of industrialization and urbanization has exacerbated global water pollution. Chemical Oxygen Demand (COD) serves as a crucial metric for assessing organic contamination in aquatic environments. Consequently, the spatiotemporal characteristics and driving factors of COD emissions have emerged as a significant area of current research interest. This study employs spatial autocorrelation and geodetector methods to rigorously analyze the spatial–temporal patterns and principal drivers of COD emissions in China’s wastewater, drawing on eleven geographic and socio-economic datasets spanning from 2011 to 2019. This study indicates that COD emissions in China’s wastewater have consistently decreased annually between 2011 and 2019, with a marked reduction observed post-2016. Regarding spatial distribution, COD emissions in the eastern region significantly surpass those in the western region, highlighting pronounced regional disparities. The analysis of the global Moran’s Index indicates that the COD emissions across China’s provincial regions demonstrate spatial clustering of similar values, with this clustering intensifying annually. Furthermore, the local Moran’s Index identifies the precise locations of these spatial clusters. Geodetector analysis identified that the consumption of nitrogen fertilizers and the consumption of chemical fertilizers had substantial impacts on COD emissions, whereas the proportion of urban population at year-end and the number of granted inventions exerted lesser effects. Furthermore, the interaction between two factors notably enhances the explanatory power regarding COD emissions. This research underpins the formulation of efficacious pollution control and environmental protection strategies, contributing vital insights for the stewardship of water quality.

Bioenergetic assessment of the use of fertilizers for potatoes in the northern region of Kazakhstan

In field experiments, the high energy efficiency of the use of mineral fertilizers for potatoes on chestnut soils of northern Kazakhstan was revealed. The energy efficiency of the use of nitrogen, phosphorus and potash fertilizers has been established. The energy consumption of nitrogen fertilizers per 1 kg of increase in the yield of the main product, depending on the doses of fertilizers, ranged from 6223,3 MJ (efficiency = 2,2 units) to 15129,6 MJ (efficiency = 1,0 units). The energy content of 1 kg of phosphorous fertilizers used by increasing the yield of potato tubers (c) was estimated from 11712 MJ (efficiency = 1,9 units) to 18300 MJ (efficiency = 2,5 units), which indicates high energy efficiency. Energy costs varied in the range of 5130,5 MJ against the background of N45K45 and 7208,3 MJ against the best variant of N45P90K45. The energy efficiency from the use of potash fertilizers is estimated at 2,2 units for variants K45 and K90 against the background of N45P45. Energy costs are reduced by obtaining 1 c of potato tubers in more efficient variants in terms of the energy efficiency of the fertilizers used. Knowing the energy costs (Ao, MJ) for growing crops and the energy content (Vf0, MJ/ha) in the yield of products, it is possible to conduct a bioenergetic assessment of the effectiveness of crop cultivation in the practice of applying fertilizers. The purpose of the research is to identify the bioenergetic efficiency of the use of mineral fertilizers for potatoes on chestnut soil in the conditions of the Northern region of Kazakhstan.

Annual consumption and types of synthetic nitrogen fertilizers: Ammonia emission indicators for mitigation strategies in the European Union

Anthropogenic ammonia (NH3) emissions are primarily derived from agricultural activities. NH3 emissions from synthetic nitrogen (N) fertilizers are associated with the annual consumption of various N fertilizers. In this study, the annual consumption of different types of synthetic N fertilizers in the EU countries, derived from the database of the International Fertilizer Association, was analyzed, and the implementation of mitigation measures for NH3 emissions at the national level was assessed. NH3 emissions were estimated using the emission factors of different N fertilizers in cool, temperate and hot climates, and low- and high-pH soils, as the European Environment Agency proposed. The results revealed that the annual consumption of various synthetic N fertilizers (average values from 2016 to 2020) varied markedly in different EU countries. France, Germany, Poland, Spain, and the United Kingdom had the largest annual consumption of synthetic N fertilizers. NH3 emissions from urea-based fertilizers are the highest in most EU countries. The annual NH3 emissions were associated with the type of synthetic N fertilizer consumed. For example, although the annual synthetic N fertilizer consumption in Germany was 38% and 41.5% higher than those in Spain and Italy, the annual NH3 emissions in Germany were 63% and 20% lower than those in Spain and Italy, respectively, due to the high proportion of urea-based fertilizers with the highest emission factor among the synthetic N fertilizers in Spain and Italy. Thus, mitigation strategies should be tailored to specific types of N fertilizers with high emission factors and proportions to minimize NH3 emissions. Since the NH3 emissions from urea-based fertilizers are the highest in the EU countries, especially in the top five countries, we recommend the addition of urease inhibitors to urea fertilizers as one important strategy for mitigating NH3 emissions.

Estimating the Sustainable Efficiency and Economic Efficiency of Vegetable Crop Growers in Baghdad Governorate

The research aims to measure the sustainability value and efficiency of sustainable for vegetable crops in the Baghdad governorate. Additionally, it aims to assess the economic efficiency for the agricultural season of 2022-2023. The research sample includes 182 farmers from the studied province, analyzed using the Data Envelopment Analysis (DEA) method. The explanatory variables for sustainability value include factors such as cultivated area, working hours, capital excluding land rent, household consumption of vegetable crops, fuel, and nitrogen fertilizer. The dependent variable is agricultural production value. The variables for sustainable efficiency encompass cultivated area, seed quantity, fertilizer quantity, pesticide quantity, number of workers, and irrigation frequency. The results indicate that there is a sustainable value for the utilized resources, reaching approximately 1.6. Moreover, the sustainability efficiency reaches about (1.2). This implies that despite resource wastage, farmers have positive and satisfactory productivity. However, the average economic efficiency is around 70.81%, revealing that vegetable crop farmers in Baghdad’s province have not achieved full economic efficiency of 100%. There is a notable variation in achieving these levels, necessitating changes in the utilization of production inputs to enhance productivity. The research recommends that farmers should redistribute resources to minimize waste, aiming to reach the optimal combination that maximizes profits while minimizing costs. This could be achieved by seeking guidance from experienced farmers and experts or by providing training on modern technology usage and mechanization of production resources. Furthermore, the research suggests the importance of conducting further studies on cost-return variation and resource utilization to evaluate sustainability.

An Analytical Economic Study of the Production and Consumption of Nitrogen Fertilizers in Egypt

An Analytical Economic Study of the Production and Consumption of Nitrogen Fertilizers in Egypt

Estimating energy consumption and GHG emissions in crop production: A machine learning approach

It is necessary to observe the relationship between the energy inputs and outputs of agricultural production in the context of long-term strategies to determine optimal sustainable solutions and identify the most susceptible system components. Comprehensive research to assess energy performance data over a relatively long-term is required to predict crop production and greenhouse gas (GHG) emissions based on energy inputs. This study collects and analyzes energy inputs and GHG emissions from 17 crops of Iran in five major categories (cereal, pulse, oilseed, fiber, and tubers) during 1970–2019 to quantify the long-term energy efficiency of major crops. Three machine learning (ML) algorithms are developed to quantify the relationship between the resources consumed per unit of energy output and GHG emission models. These models are evaluated through three quantitative statistics. The analysis considers all physical and chemical inputs used to produce the major crops. These energy variables include human labor, machinery, fossil fuels, electricity, irrigation water, fertilizers (phosphate, nitrogen, and potassium), pesticides and seed rate. The results revealed that the input and output energy values increased from 39.47 to 190.18 MJ ha-1 in 1970 to 253.43 and 654 MJ ha−1 in 2019. The GHG emissions from electricity (47.1%) were followed by those of nitrogen fertilizer (25.75%). Reducing the consumption of electricity and nitrogen fertilizers is the most efficient options to improve the energy efficiency of the crops studied.

Effects of saline water and N levels on eggplant (Solanum melongena L.) fruit yield, water productivity, and nitrogen use efficiency by drip and surface flood irrigation

Due to a scarcity of freshwater resources, agriculture is dependent on the use of poor quality water for irrigation in arid and semi-arid regions. Hence, the effective use of poor quality water requires pioneering water management and nitrogen fertilizer practices for increasing yield and resource efficiency. This study aimed to investigate the effect of saline water levels, nitrogen fertilizer, and irrigation methods on eggplant yield, water productivity, NPK uptake, and nitrogen use efficiency. The experiment was conducted in 2019 and 2020 under drip (IM1) and surface flood irrigation (IM2). The treatments included three saline water levels i.e. canal water (SW1), ECiw=2.5 dS/m (SW2), and ECiw=5.0 dS/m (SW3) along with the three nitrogen levels of 75% (N1), 100% (N2), and 125% (N3) of the recommended dose of nitrogen. Application of saline water using IM1 reduced the ECe by 41.8% (SW2) and 34% (SW3) over IM2. The fruit yield, water productivity (WP), NPK uptake, and nitrogen use efficiency (NUE) was increased by 22%, 127.6%, 39.8%, 16.6%, 11.8%, and 23.8% under IM1 over IM2, respectively. A high saline water level under IM2 can cause more reduction in fruit yield, NPK uptake, and water use. Applying saline water through IM1 improves fruit yield, WP, and NUE by 13-32.8%, 104.1-147.3%, and 10.5-35.2% as compared to IM2. We found that saline water and N applied by drip improved eggplant yield, water productivity, and NPK uptake. It is concluded that irrigation water and nitrogen fertilizer consumption are optimized when saline water is applied through drip irrigation.

Risk of Nitrate Residues in Food Products and Drinking Water

Although nitrate is the essential nutrient of our body, the excess amount of it as residues strongly causes disease. Nitrate comes from plant and animal foods that are vital to our metabolism. The nitrate is absorbed through the soil by plants and becomes an herbal protein that is placed in the food chain. If the nitrate is absorbed more than the plant requirement, it will be accumulated into the plant’s organs. Since nitrogen fertilizers increase the weight and yield of the plants, farmers consume large amounts of which. Hence, we investigate the consumption of nitrogen fertilizers in the world and the standard allowable residual nitrate in food and water considering the accumulation of nitrate in water and food. Excess amount of nitrate in the soil enters the drinking water after leaching or directly transported from groundwater to surface water and drinking water. The entry of the excess amount of nitrate from food products and drinking water into our bodies causes dangerous diseases such as different types of cancers, methemoglobinemia, osteoporosis, kidney stones, and some other diseases. The present article, besides indicating the benefits of nitrate for Treatment purposes and demonstrating the state of nitrate accumulation in food and water as well as its standards, deals with diseases caused by it and presents some remedies to reduce the risks.

Environmental Impacts of Biodiesel Production Cycle from Farm to Manufactory: An Application of Sustainable Systems Engineering

One of the key challenges in using fossil fuels is the environmental impacts of these energy sources, and to reduce these destructive effects, the use of renewable energy sources (biofuels) is necessary. One of the important biofuels is biodiesel, which can be produced from cottonseed. To properly manage the chain dealing with biodiesel production from the cottonseed chain (from farm to manufactory), environmental hotspots must be pinpointed. In the present study, it was attempted to examine the environmental impacts of the biodiesel production cycle from cottonseed (agronomic stages, ginning, oiling, and biodiesel production). The data obtained in all three stages were analyzed by the Impact 2002+ method in the SimaPro software. The highest contribution to creating environmental indicators at the agricultural stage was related to the use of nitrogen fertilizers, direct emission from the farm and fossil fuels, the ginning and oiling stage involving the use of diesel fuel and sulfuric acid, and the production of biodiesel in the manufactory involving the use of methanol and electricity. The potential environmental impacts of a functional unit of 1 kg of biodiesel include: human health, 9.05–10−6 (DAYLY); ecosystem quality, 1.369 (PDF*m2*year); climate changes, (kg CO2 eq.) 17.247; and resources (MJ primary), 89.116. Results showed that agriculture has more significant participation in the environmental impact than other sections (ginning and oiling and biodiesel production), especially due to the application of fertilizers and fuel. Surveying the environmental indicators of the results showed that at the agricultural stage, the human health indicator is 10.43, 1.21, and 5.32 times higher than the ecosystem quality, climate change, and resource indicators, respectively; at the ginning and oiling stages, it is 2.35, 31.68, and 2.09 times higher, respectively; and at the stage of biodiesel production in the manufactory, it is 16.41, 1.96, and 0.99 times higher, respectively, in terms of the destructive effects. The overall results showed that the hotspot points in the present study can be largely modified by reducing the consumption of nitrogen fertilizers, using new equipment and machinery, ginning and oiling, and using fewer methanol ratios than oil.

Effect of Agricultural Structure Adjustment on Spatio-Temporal Patterns of Net Anthropogenic Nitrogen Inputs in the Pearl River Basin from 1990 to 2019

Worldwide urbanization has brought dramatic changes in agricultural structures, as well as serious agricultural non-point source pollutions of nitrogen and phosphorus. However, understanding the effect of agricultural structure adjustment on net anthropogenic nitrogen inputs (NANI) has been still limited. In this paper, statistical data from the agricultural statistical Yearbook, the National Economic and Social Development Statistical Bulletin were collected from 1990 to 2019 in the Pearl River Basin, China, and used to analyze the spatial and temporal patterns of NANI and its influencing factors. The results indicated that the agricultural structure adjustment has significantly influenced the spatial and temporal patterns of NANI in the last 30 years in the Pearl River Basin. The NANI decreased from 1990 to 2019, and had a spatial pattern of higher values in the upstream areas and lower in the downstream areas. In terms of the nitrogen input sources of NANI, in the economically developed regions downstream, nitrogen inputs are dominated by food/feed nitrogen, which accounted for an average of 49.6% of total nitrogen inputs. In upstream areas with relatively low economic development, fertilizer nitrogen accounted for an average of 54.9% of total nitrogen inputs. A novel nitrogen input source index of NANI, namely the ratio of agricultural nitrogen inputs to non-agricultural nitrogen inputs of NANI(ASNA), was also proposed to characterize the impact of the agricultural industry restructuring on NANI changes over time. Similar to the characteristics of NANI from 1990 to 2019, the ASNA showed a decreasing trend in the study area. Moreover, agricultural variables (agricultural land area, nitrogen fertilizer consumption and livestock farming density) tended to contribute less to the explained ASNA variances, while the contributions of the non-agricultural factors (population density and non-agricultural GDP) increased from 1990 to 2019. This indicated that the contribution of nitrogen inputs from agricultural sources to the NANI decreased while the contribution of nitrogen inputs from non-agricultural sources increased, with the shifts of agricultural sectors to the secondary and tertiary sectors in the Pearl River Basin. Our findings also suggest that differently regional targeting should be considered for the nitrogen pollution management in the Pearl River Basin, which focuses on the nitrogen pollution management of non-agricultural sources in the downstream areas, and but highlights agricultural nitrogen pollution management in the upstream areas.

Greenhouse gas emission and energy analysis of vetch (Vicia sativa L.) cultivation

BackgroundAgricultural production accounts for a major share of global energy consumption and greenhouse gas emissions (GHG). However, the information on energy use and GHG emissions from various crops is contradictory. Climate change is expected to increase the GHG emission from different crops; therefore, selection of the crops with lower GHG emission could be helpful in reducing the emission and energy consumption. A major focus of energy policy should be on improving energy efficiency. Saving money and lowering GHG emissions are only two benefits of using energy efficiently. However, these are unknown for the vetch cultivation in Siirt province of Turkey. MethodsThis study investigated energy consumption efficiency and GHG emissions of vetch (Vicia sativa L.) production under dry circumstances in Siirt province, Turkey during 2021. Seed rate was kept 120 kg/ha in the current study. The amount of fertilizer applied was 92.0 kg/ha pure phosphorus and 36.0 kg/ha pure nitrogen. To calculate the energy efficiency of vetch production in Siirt, energy inputs and energy outputs were computed. ResultsThe energy intake and output were 8205.02 MJ/ha and 90388.56 MJ/ha, respectively. The energy inputs were: 37.1 % diesel fuel energy, 31.2 % fertilizer energy, 21.2 % seed energy, 9.6 % equipment energy, and 0.9 % labor energy. The results revealed that energy consumption efficiency was 11.02, specific energy was 0.34 MJ/kg, energy efficiency was 2.90 kg/MJ, and net energy was 82183.54 MJ/ha in vetch production. Total GHG emissions from vetch production was 205.19 kgCO2-eq ha−1, with diesel fuel accounting for the lion's share (72.88 %). Diesel fuel was followed by the consumption of nitrogen fertilizer (26.33 %), phosphorous (0.47 %) and machinery (0.42 %). Additionally, GHG ratio was 0.009 kg CO2-eq kg−1 in vetch production. ConclusionIt is concluded that encouraging the farmers to produce vetch as an alternative to the production of conventional forage crops and rotation in fodder production will be beneficial. It will reduce GHG emissions with lesser energy consumption.

Energy Analysis for Two Production Systems of Cucumber

This research, conducted in Gotvand, southwest of Iran, compared the energy consumption of two cucumber production systems: field and greenhouse production systems. In this study, energy inputs of two production systems of cucumber (including seed, pesticide, human labor, machinery, diesel fuel, electricity, organic manure, chemical fertilizer) were determined from questionnaires completed by farmers. The results of the experiment indicated that the energy input of the two cultivation systems was not significantly different in input energies. In both cucumber production systems, the most input energy was allocated to nitrogen fertilizer (57% and 53% for field and greenhouse, respectively) followed by diesel fuel (21% in both production systems). Non-renewable energies accounted for 90 and 88% of the total energy input to the farm and greenhouse systems, respectively. Total output energy of field and greenhouse cucumber production system was 33000 and 34000 MJ, respectively. Reducing the consumption of nitrogen fertilizer through the use of appropriate crop rotation is a suitable solution to improve energy efficiency in the cucumber production system.

Historical nitrogen fertilizer use in China from 1952 to 2018

Abstract. China ranks in the highest position for nitrogen (N) fertilizer consumption in the world. Although N fertilizer use has greatly contributed to the China's food production, this has also caused an unprecedented alteration in the biogeochemical cycles and endangered terrestrial and aquatic ecosystems. Existing use of N fertilizers in China, as shown by digital maps, is usually coarse in resolution and intermittently covered with a biased gridded dataset. Here, we have reconstructed a historical, annual N fertilizer use dataset in China and resampled it to 5 km×5 km resolution, covering the period from 1952 to 2018 by integrating improved cropland maps. Results showed that most of the N input was directly applied as N-only fertilizer, while the contribution from compound fertilizers has ranged between 16 % and 24 % since 1980. The national total N fertilizer input increased from 0.06 Tg N yr−1 (0.05 g N m−2 yr−1) in 1952 to 31.15 Tg N yr−1 (18.83 g N m−2 yr−1) in 2014 and then decreased to 28.31 Tg N yr−1 (17.06 g N m−2 yr−1) in 2018. Despite the total N input decreasing by 9.1 % (2.84 Tg N yr−1) from 2014 to 2018, the N input from compound fertilizers has increased by 6 % (0.43 Tg N yr−1) during the corresponding period. The previous Food and Agriculture Organization (FAO) data-based N fertilizer products in China overestimated N use in low cropland coverage areas but underestimated N use in high cropland coverage areas. However, our newly reconstructed data have not only corrected the existing biases and improved the spatial distribution but have also shown that vegetable and other crops (e.g., orchards), but not grain crops, are the most intensively fertilized crops in China, implying the importance of quantifying greenhouse gas (GHG) emissions from these croplands. We argue that the reconstructed, spatially explicit N fertilizer use data in this study are expected to contribute to better understanding of biogeochemical cycles, including the simulations of GHG emissions and food production in China. The spatially explicit N fertilizer use and the crop-specific N fertilizer use datasets are available via an open data repository (https://doi.org/10.6084/m9.figshare.21371469.v1; Yu, 2022).

Can e-commerce alleviate agricultural non-point source pollution? — A quasi-natural experiment based on a China's E-Commerce Demonstration City

Agricultural non-point source pollution is an important driving factor that causes systemic pollution of the ecological environment and directly threatens the sustainable development of agriculture, human health, and safety. As a new engine to reshape the agricultural development model, e-commerce is of great significance to the mitigation of agricultural non-point source pollution. This study regards China's National E-commerce Demonstration Cities (NEDCs) as a quasi-natural experiment and uses the Multi-period difference in difference (DID) method to investigate the impact of urban e-commerce development on agricultural non-point source pollution and its mechanism. The results show that compared with the control group, the NEDC policy reduced the total fertilizer consumption in the pilot cities by 7.5 percentage points, and at the same time had a reduction effect on the consumption of nitrogen fertilizers, pesticides, and agricultural films. According to the analysis of the underlying mechanism, this abatement effect is achieved by increasing the economic performance of the NEDC pilot cities represented by GDP and GDP per capita, and promoting technological innovation represented by green patents and green utility patents. The analysis of heterogeneity finds that the reduction effect of e-commerce on agricultural non-point source pollution is stronger in areas such as main grain production areas and high-value agrochemical input areas. Accordingly, this study proposes that the government should pay attention to regional heterogeneity and formulate support policies for agricultural e-commerce based on local conditions. Moreover, we should actively advance the development of the new business model of “e-commerce + agriculture” and promote the organic integration of agricultural development and ecological civilization.

Analysis of Growth Trends of Production and Consumption of Fertilizer Nutrients in India

The present study was carried out to determine the trend in production and consumption in India from 1990-91 to 2019-20. The study had been divided into three phases viz. I period (1990-91 to 1999-2000), II period (2000-01 to 2009-10) and III (2010-11 to 2019-20). The compound growth rates (CGRs) of production and consumption were estimated as for three phases as well as for the overall period. The consumption of fertilizer is continuously increased year by year. Only nitrogen fertilizer shows positive growth i.e., 0.35 per cent. The annual growth rate of consumption of Nitrogen, phosphatic and potassic fertilizer is 3.04, 3.77 and 4.09 per cent respectively between 1990-91 to 2018-19. The highest growth of consumption has been registered in potassic fertilizer. However, after 2010-11 there is a negative trend and considerable decline in fertilizer use. The growth rate falls to -0.21 per cent, with phosphatic fertilizer decline at -1.29 per cent and potassic fertilizer at -0.31 per cent.

Nitrogen fertilizer consumption and nitrous oxide emissions associated with ethanol production – A national-scale comparison between Brazilian sugarcane and corn in the United States

Globally, Brazil and United States (US) have the large-scale programs of biofuels production. Among other parameters, the feasibility and sustainability of petroleum-based fuels by biofuels replacement depend upon the proper nitrogen (N) fertilizers usage as well as the associated nitrous oxide (N2O) emissions along the production chain. The efficiency of N use also depends on the choice of biofuel crop. Previous studies indicated that sugarcane (Saccharum spp.) requires less N than corn (Zea mays L), thus, the hypothesis tested was that Brazilian sugarcane-based ethanol requires less synthetic N inputs per unit produced than corn-based ethanol in the US. Consequently, ethanol production in Brazil from sugarcane has lower N2O emissions associated with N fertilization than ethanol produced in the US from corn. Here, we reviewed national-scale dataset on sugarcane and corn cultivation in Brazil and US respectively, in order to compare temporal changes in the cultivated area for both crops (devoted for ethanol production), N-fertilizers consumption, and associated emission of N2O in the period 2000–2020. The same parameters were forecasted for the upcoming decade. For both periods, there were calculated two indexes: the N-fertilizer consumption index (the quotient of N-fertilizer input by ethanol production) and the N2O emission index (the quotient of N-fertilizer input by N2O emission). In the period 2000–2020, the devoted area for sugarcane and corn cultivation increased around 43 and 9%, respectively, while the N rates recorded in 2020 for sugarcane in Brazil and corn in the US averaged, respectively, 78 and 167 kg ha−1 N. Moreover, within the 2000–2020 period, the average yield was 74 Mg ha−1 for sugarcane (stalks) in Brazil and 9.6 Mg ha−1 for corn (grain) in the US, which resulted in ethanol yield (in area basis) of 6009 and 4003 L ha−1, respectively. Thus, the N-fertilizer consumption index was much lower for sugarcane-based ethanol than for corn-based ethanol (0.009 versus 0.04 kg N L−1). Through the Intergovernmental Panel on Climate Change (IPCC) emission factor (Tier 1), we estimated that N2O emission is 4.6 times lower for sugarcane-based ethanol than for corn-based ethanol (94 versus 433 mg N2O per L−1). By 2030, ethanol production might reach 45 and 58 billion L in Brazil and within the US, respectively, leading to 0.45 and 2.07 million t of N-fertilizer consumption per year−1 for sugarcane and corn respectively. The outcomes herein endorse the sustainability of sugarcane as a feedstock for ethanol production and may guide stakeholders to establish public policies to enable sugarcane-based ethanol production as one alternative to tackle global warming and climate changes.

Food waste and its embedded resources loss: A provincial level analysis of China

Food waste is of great concern because it causes severe environmental pollution during disposal and contains many resources that should be well managed. Food waste quantification could clarify the resource value of wasted food and thus help to improve resource utilization efficiency, reduce water eutrophication potential, and reduce greenhouse gas emissions. By considering household food waste, out-of-home food waste, and food delivery waste in rural and urban regions, this paper quantifies the nitrogen, phosphorus, water, and carbon footprint embedded in China's food waste at the provincial level. The results indicate that food waste in China was 56.75 Mt. in 2018. Those wasted food cause 0.54 Mt. loss of phosphorus (5.12% of the phosphorus fertilizer consumption), 3.58 Mt. loss of nitrogen (10.43% of the nitrogen fertilizer consumption), and 120.25 billion tons loss of water (3.06 times of the storage capacity of the Three Gorges Reservoir). If ignoring the greenhouse gas emissions caused by land-use change, the carbon footprint caused by wasted food is 168.07 Mt. CO2eq, accounting for 1.44% of China's total GHG emission. Principal component analysis indicates that the per capita disposable income, urbanization rate, and personal consumption expenditure are critical factors for food waste volume variation in different provinces. Considering China's significant role in the global resource cycling, improving nutrient/resource utilization efficiency along the food supply chain, minimizing food waste volume, and developing economic-effective processes for food waste reuse and recycling are recommended to close the imbalanced resource cycle during the current food waste management.

Exogenous application and interaction of biochar with environmental factors for improving functional diversity of rhizosphere's microbial community and health

The usage of fertilizer with high nitrogen content in many countries, as well as its enormous surplus, has a negative impact on the soil ecological environment in agricultural system. This consumption of nitrogen fertilizer can be minimized by applying biochar to maintain the sufficient supply of nitrogen as nutrient to the near-root zone. This study investigated the effects of various amounts of biochar application (450, 900, 1350, and 1800 kg/hm2) and reduction of nitrogen fertilizer amount (10, 15, 20, and 25%) on the nutrients and microorganism community structure in rhizosphere growing tobacco plant. The microorganism community was found essential in improving nitrogen retention. Compared with conventional treatment, an application of biochar in rhizosphere soil increased the content of soil available phosphorus, organic matter and total nitrogen by 21.47%, 26.34%, and 9.52%, respectively. It also increased the abundance of microorganisms that are capable of degrading and utilizing organic matter and cellulose, such as Actinobacteria and Acidobacteria. The relative abundance of Chloroflexi was also increased by 49.67–78.61%, and the Acidobacteria increased by 14.79–39.13%. Overall, the application of biochar with reduced nitrogen fertilizer amount can regulate the rhizosphere microecological environment of tobacco plants and their microbial population structure, thereby promoting soil health for tobacco plant growth while reducing soil acidification and environmental pollution caused by excessive nitrogen fertilizer.

Greenhouse gas emissions and mitigation potential of hybrid maize seed production in northwestern China

Although hybrid maize seed production is one of the most important agriculture systems worldwide, its greenhouse gas (GHG) emissions and potential mitigation measures have not been studied. In this study, we used life cycle assessment (LCA) to quantify the GHG emissions of 150 farmers run by 6 companies in an area of northwest China known for hybrid maize seed production. The results indicated that the average reactive nitrogen (Nr) losses and GHG emissions from hybrid maize seed production were 53 kg N ha-1 and 8077 kg CO2 eq ha-1, respectively. Furthermore, the average nitrogen and carbon footprints of the process were 12.2 kg N Mg-1 and 1495 kg CO2 eq Mg-1, respectively. Nitrogen fertilizer and electricity consumption for irrigation were the main contributors to high GHG emissions, accounting for 60% and 30% of the total, respectively. The GHG emissions from seed production for different companies varied greatly with their resource input. There was also a large variation in environmental burdens among the 150 farmers. Based on an analysis of the yield group, we found that the carbon footprint of the first group (the one with the highest yield) was 27% lower than the overall average. Scenario analysis suggests that a combined reduction of N input rate, optimizing irrigation, and increasing yield can eventually mitigate the carbon footprint of hybrid maize seed production by 37%. An integrated systematic approach (e.g., ISSM: integrated soil-crop system management) can reduce the GHG emissions involved in producing hybrid maize seeds. This study provides quantitative evidence and a potential strategy for GHG emissions reduction of hybrid maize seed production.

Effects of Sod-culture on Soil Nutrients and Microbial Abundance in Zanthoxylum bungeanum Plantation

In order to study the impacts of sod-culture on soil nutrients and soil microorganisms under Zanthoxylum bungeanum plantation, white clover was planted and natural weeds were cultivated, and the changes of soil nutrients and soil microorganisms were studied with clear tillage as control. The results showed that the effect of grass on soil nutrients and microbial abundance was mainly in 0~20 cm soil layer in Zanthoxylum bungeanum plantation. Grass increased the content of soil organic matter, some nutrient elements, the microbial abundance in soil, and changed the population structure of microorganisms. At the early stage of grass growing, the consumption of soil water and nitrogen fertilizer may be great, so scientific management combined with agricultural measures should be carried out according to the growth characteristics of Zanthoxylum bungeanum.