Vertical and horizontal variabilities of ammonia in an agricultural area of Southeast China.

Ammonia (NH) plays a crucial role in the global nitrogen cycle, the increased NH emissions from agricultural activities impacting air, soil, water quality, and human health. Accurately estimating both the vertical and horizontal transport distances of NH are important for effective pollution control. Therefore, we used a helium-filled balloon mounted sampler to analyze the vertical profiles of NH emissions and their seasonal variations in an agricultural area of southeast China.

A dataset for N natural abundance of soil ammonia volatilization.

Investigating the sources of ammonia (NH) in the atmosphere and the contribution of each source is essential for environmental pollution control. The presented dataset aims to provide N natural abundance (δN) data collected from different controlled treatments to fill the knowledge gap between insufficient data of soil δN-NH and accurately identifying atmospheric NH source apportionments. Our results showed that the overall δN-NH values emitted from soil ranged from -46.

Changes in source composition of wet nitrate deposition after air pollution control in a typical area of Southeast China.

In recent years, China has adopted numerous policies and regulations to control NO emissions to further alleviate the adverse impacts of NO-N deposition. However, the variation in wet NO-N deposition under such policies is not clear. In this study, the southeastern area, with highly developed industries and traditional agriculture, was selected to explore the variation in NO-N deposition and its sources changes after such air pollution control through field observation and isotope tracing.

Thirty years of experience in water pollution control in Taihu Lake: A review.

Taihu Lake has suffered from eutrophication and algal blooms for decades, primarily due to increasing anthropogenic pollutants from human activities. Extensive research and widespread implementation of water pollution control measures have significantly contributed to the improvement of water quality of Taihu Lake. However, the relevant experience of Taihu Lake pollution control has not been well summarized to provide insight for future lake restoration.

Traceability of atmospheric ammonia in a suburban area of the Beijing-Tianjin-Hebei region.

Ammonia (NH) is one of the most important sources that have been linked to the formation of PM. Therefore, it is important to study the source contributions to atmospheric NH for air pollution control. Here we used N natural abundance (expressed by δN) values to quantify the source contributions to atmospheric NH in the Beijing-Tianjin-Hebei (BTH) region, which suffers from the country's worst air pollution.

[Runoff Simulation and Its Response to Extreme Precipitation in the Yangtze River Basin].

Studies on runoff are crucial for the scientific allocation, utilization, and development of water resources and can provide an important basis for the prevention and control of flood and drought disaster, as well as water environmental pollution management. Affected by global warming, the frequency and intensity of extreme climate events, particularly extreme precipitation, have significantly changed in recent years, which can directly or indirectly impact runoff changes. In this study, we used the SWAT model to simulate the spatiotemporal variations in runoff in the Yangtze River Basin from 1965 to 2019 and analyzed the response of runoff to precipitation under extreme conditions.

[Assessment of Critical Loads of Nitrogen Deposition in Natural Ecosystems of China].

Excessive nitrogen (N) deposition causes a series of environmental problems, including biodiversity loss. Therefore, assessing current N deposition thresholds of natural ecosystems is critical for regional N management and pollution control. In this study, the critical loads of N deposition in mainland China were estimated using the steady-state mass balance method, and the spatial distribution of ecosystems that exceeded the critical load was evaluated.

Integrated biochar solutions can achieve carbon-neutral staple crop production.

Agricultural food production is a main driver of global greenhouse gas emissions, with unclear pathways towards carbon neutrality. Here, through a comprehensive life-cycle assessment using data from China, we show that an integrated biomass pyrolysis and electricity generation system coupled with commonly applied methane and nitrogen mitigation measures can help reduce staple crops' life-cycle greenhouse gas emissions from the current 666.5 to -37.

Traceability of nitrate polluted hotspots in plain river networks of the Yangtze River delta by nitrogen and oxygen isotopes coupling bayesian model.

The adverse effects of increased nitrate (NO) pollution especially from the non-point source on the hydrosphere and anthroposphere are becoming more prominent. The non-point-derived NO in the rivers supplying the upstream threatens the aquatic ecosystem of Taihu Lake. Here, dual-stable isotopes (δN and δO) of NO were applied to the Bayesian model (SIAR) for quantitative source identification of reactive nitrogen (Nr) in a mixed agricultural and urban region along the complex river network of the Yangze River delta.

Standoff sub-ppb level measurement of atmospheric ammonia with calibration-free wavelength modulation spectroscopy.

Ammonia (NH) plays a significant role in the formation of atmospheric particulate matter, and influences on environmental and public health as well as climate change. Thus, it is important to sensitive measurement of atmospheric NH. In the present work, a sub-ppb level standoff open-path NH sensor was developed for on line, sensitive measurement of atmospheric NH.

Temporal and spatial variations in nitrogen use efficiency of crop production in China.

The low value of nitrogen use efficiency (NUE) (around 30%) of crop production in China highlights the necessity to adopt reasonable N managements in national scale. After the implementation of 'National Soil Testing and Formulated Fertilization' program in 2005, many field experiments have reported an increase of NUE for crop productions in China. This has prompted discussion regarding the extent to which NUE in crop production has been improved.

Changes of δN values during the volatilization process after applying urea on soil.

Ammonia (NH) volatilized from soils plays an important role in N cycle and air pollution, thus it is important to trace the emission source and predict source contributions to development strategies mitigating the environmental harmful of soil NH volatilization. The measurements of N natural abundance (δN) could be used as a complementary tool for apportioning emissions sources to resolve the contribution of multiple NH emission sources to air NH pollution. However, information of the changes of δN-NH values during the whole volatilization process under different N application rates are currently lacking.

Potential for mitigating global agricultural ammonia emission: A meta-analysis.

Ammonia (NH) emission from agricultural sources has contributed significantly to air pollution, soil acidification, water eutrophication, biodiversity loss, and declining human health. Although there are numerous strategies for reducing NH emission from agricultural systems, the effectiveness of these measures is highly variable. Furthermore, the integrated assessment of measures to reduce NH emission both from livestock production and cropping systems based on animal and crop type is lacking.

Determining δN-NO values in soil, water, and air samples by chemical methods.

Soil, water, and air NO pollution is a major environmental problem worldwide. Stable isotope analysis can assess the origin of NO because different NO sources carry different isotope signatures. Hence, using appropriate chemical methods to determine the δN-NO values in different samples is important to improve our understanding of the N-NO pollution and take possible strategies to manage it.

Dissimilatory Nitrate Reduction Processes in Typical Chinese Paddy Soils: Rates, Relative Contributions, and Influencing Factors.

Using soil slurry-based (15)N tracer combined with N2/Ar technique, the potential rates of denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA), and their respective contributions to total nitrate reduction were investigated in 11 typical paddy soils across China. The measured rates of denitrification, anammox, and DNRA varied from 2.37 to 8.

Linking river nutrient concentrations to land use and rainfall in a paddy agriculture-urban area gradient watershed in southeast China.

The effects of land use and land-use changes on river nutrient concentrations are not well understood, especially in the watersheds of developing countries that have a mixed land use of rice paddy fields and developing urban surfaces. Here, we present a three-year study of a paddy agricultural-urban area gradient watershed in southeast China. The annual anthropogenic nitrogen (N) input from the agricultural region to the urban region was high, yet the results showed that the monthly nutrient concentrations in the river were low in the rainy seasons.

Greenhouse gas emissions and reactive nitrogen releases during the life-cycles of staple food production in China and their mitigation potential.

Life-cycle analysis of staple food (rice, flour and corn-based fodder) production and assessments of the associated greenhouse gas (GHG) and reactive nitrogen (Nr) releases, from environmental and economic perspectives, help to develop effective mitigation options. However, such evaluations have rarely been executed in China. We evaluated the GHG and Nr releases per kilogram of staple food production (carbon and Nr footprints) and per unit of net economic benefit (CO2-NEB and Nr-NEB), and explored their mitigation potential.

Characteristics of nitrogen balance in open-air and greenhouse vegetable cropping systems of China.

Nitrogen (N) loss from vegetable cropping systems has become a significant environmental issue in China. In this study, estimation of N balances in both open-air and greenhouse vegetable cropping systems in China was established. Results showed that the total N input in open-air and greenhouse vegetable cropping systems in 2010 was 5.

Field monitoring of a LID-BMP treatment train system in China.

In order to assess the urban runoff control effectiveness of a low-impact development best management practice (LID-BMP) treatment train system, a field test of selected LID-BMPs was conducted in China. The LID-BMPs selected include three grassed swales, a buffer strip, a bioretention cell, two infiltration pits, and a constructed wetland. The test site is in a campus in southern China.

Nitrogen removal capacity of the river network in a high nitrogen loading region.

Denitrification is the primary process that regulates the removal of bioavailable nitrogen (N) from aquatic ecosystems. Quantifying the capacity of N removal from aquatic systems can provide a scientific basis for establishing the relationship between N reduction and water quality objectives, quantifying pollution contributions from different sources, as well as recommending control measures. The Lake Taihu region in China has a dense river network and heavy N pollution; however, the capacity for permanent N removal by the river network is unknown.

Spatial and temporal variations of river nitrogen exports from major basins in China.

Provincial-level data for population, livestock, land use, economic growth, development of sewage systems, and wastewater treatment rates were used to construct a river nitrogen (N) export model in this paper. Despite uncertainties, our results indicated that river N export to coastal waters increased from 531 to 1,244 kg N km(-2) year(-1) in the Changjiang River basin, 107 to 223 kg N km(-2) year(-1) in the Huanghe River basin, and 412 to 1,219 kg N km(-2) year(-1) in the Zhujiang River basin from 1980 to 2010 as a result of rapid population and economic growth. Significant temporal changes in water N sources showed that as the percentage of runoff from croplands increased, contributions of natural system runoff and rural human and livestock excreta decreased in the three basins from 1980 to 2010.