Three years of CO, CH and NO fluxes from different sheepfolds in a semiarid steppe region, China.

To better assess greenhouse gas (GHG) emissions from livestock folds in semi-arid steppe zones and reduce uncertainties in regional and national GHG emission inventories, we measured the fluxes of carbon dioxide (CO), methane (CH) and nitrous oxide (NO) from sheepfolds under contrasting management regimes (i.e., summer sheepfolds under continuous and rotational grazing strategies and the winter sheepfold) for 3 consecutive years.

Alder expansion stimulates nitrogen oxide (NO) emissions from southern Eurasian permafrost peatlands.

Nitrogen oxides (NO) play an important role for atmospheric chemistry and radiative forcing. However, NO emissions from the vast northern circumpolar permafrost regions have not been studied in situ due to limitations of measurement techniques. Our goals were to validate the offline analytical technique, and based on this, to widely quantify in situ NO emissions from peatlands in the southern Eurasian permafrost region.

A global meta-analysis of yield-scaled N O emissions and its mitigation efforts for maize, wheat, and rice.

Maintaining or even increasing crop yields while reducing nitrous oxide (N O) emissions is necessary to reconcile food security and climate change, while the metric of yield-scaled N O emission (i.e., N O emissions per unit of crop yield) is at present poorly understood.

Characteristics of annual NH emissions from a conventional vegetable field under various nitrogen management strategies.

High N-fertilizer applications to conventional vegetable production systems are associated with substantial emissions of NH, a key substance that triggers haze pollution and ecosystem eutrophication and thus, causing considerable damage to human and ecosystem health. While N fertilization effects on NH volatilization from cereal crops have been relatively well studied, little is known about the magnitude and yield-scaled emissions of NH from vegetable systems. Here we report on a 2-year field study investigating the effect of various types and rates of fertilizer application on NH emissions and crop yields for a pepper-lettuce-cabbage rotation system in southwest China.

Assessing the environmental sustainability of different soil disinfestation methods used in solar greenhouse vegetable production systems.

Overuse of fertilizers and irrigation and continuous monocropping is increasingly jeopardizing vegetable production in solar greenhouses as it causes serious soil degradation and the spread of soil-borne diseases. As a countermeasure, the practice of anaerobic soil disinfestation (ASD) has been recently introduced, which is carried out during the summer fallow period. However, ASD may increase N leaching and greenhouse gas (GHG) emissions when large amounts of chicken manure are applied.

Urbanization can accelerate climate change by increasing soil N O emission while reducing CH uptake.

Urban land-use change has the potential to affect local to global biogeochemical carbon (C) and nitrogen (N) cycles and associated greenhouse gas (GHG) fluxes. We conducted a meta-analysis to (1) assess the effects of urbanization-induced land-use conversion on soil nitrous oxide (N O) and methane (CH ) fluxes, (2) quantify direct N O emission factors (EF ) of fertilized urban soils used, for example, as lawns or forests, and (3) identify the key drivers leading to flux changes associated with urbanization. On average, urbanization increases soil N O emissions by 153%, to 3.

Heavy metal and nutrient concentrations in top- and sub-soils of greenhouses and arable fields in East China - Effects of cultivation years, management, and shelter.

Although greenhouse vegetable production in China is rapidly changing, consumers are concerned about food quality and safety. Studies have shown that greenhouse soils are highly eutrophicated and potentially contaminated by heavy metals. However, to date, no regional study has assessed whether greenhouse soils differ significantly in their heavy metal and nutrient loads compared to adjacent arable land.

A synthesis of nitric oxide emissions across global fertilized croplands from crop-specific emission factors.

Nitrogen (N) fertilizer application to agricultural soils results in substantial emissions of nitric oxide (NO), a key substance in tropospheric chemistry involved in climate forcing and air pollution. However, the estimates of global cropland NO emissions remain uncertain due to a lack of information on direct NO emission factors (EF s) of applied N for various cropping systems at seasonal or annual scales. Here we quantified the crop-specific seasonal and annual-scale NO EF s through synthesizing 1094 measurements from 125 field-based studies worldwide.

Phytotoxic Effects of Polyethylene Microplastics on the Growth of Food Crops Soybean () and Mung Bean ().

Accumulation of micro-plastics (MPs) in the environment has resulted in various ecological and health concerns. Nowadays, however, studies are mainly focused on toxicity of MPs on aquatic organisms, but only a few studies assess the toxic effects of micro-plastics on terrestrial plants, especially edible agricultural crops. The present study was aimed to investigate the adverse effects of polyethylene (PE) microplastics on the germination of two common food crops of China, i.

Characteristics of annual NO and NO fluxes from Chinese urban turfgrasses.

Urban turfgrass ecosystems are expected to increase at unprecedented rates in upcoming decades, due to the increasing population density and urban sprawl worldwide. However, so far urban turfgrasses are among the least understood of all terrestrial ecosystems concerning their impact on biogeochemical N cycling and associated nitrous oxide (NO) and nitric oxide (NO) fluxes. In this study, we aimed to characterize and quantify annual NO and NO fluxes from urban turfgrasses dominated by either C4, warm-season species or C3, cool-season and shade-enduring species, based on year-round field measurements in Beijing, China.

Soil type affects not only magnitude but also thermal sensitivity of NO emissions in subtropical mountain area.

It is a concern whether the effect of soil type on NO emissions has to be considered for regional mitigation strategies and emission estimates in mountainous areas with inherent spatial heterogeneities of soil type. To date, there were few field experiments which investigated soil type effects on NO emissions. Thus a 2-year field study was conducted to measure NO emissions and soil environmental variables from three different soils that were formed from similar parental rock under the same climate.

Potential benefits of liming to acid soils on climate change mitigation and food security.

Globally, about 50% of all arable soils are classified as acidic. As crop and plant growth are significantly hampered under acidic soil conditions, many farmers, but increasingly as well forest managers, apply lime to raise the soil pH. Besides its direct effect on soil pH, liming also affects soil C and nutrient cycles and associated greenhouse gas (GHG) fluxes.

Elevated atmospheric CO reduces yield-scaled N O fluxes from subtropical rice systems: Six site-years field experiments.

Increasing levels of atmospheric CO are expected to enhance crop yields and alter soil greenhouse gas fluxes from rice paddies. While elevated CO ( ) effects on CH emissions from rice paddies have been studied in some detail, little is known how might affect N O fluxes or yield-scaled emissions. Here, we report on a multi-site, multi-year in-situ FACE (free-air CO enrichment) study, aiming to determine N O fluxes and crop yields from Chinese subtropical rice systems as affected by .

Modeling ammonia volatilization following the application of synthetic fertilizers to cultivated uplands with calcareous soils using an improved DNDC biogeochemistry model.

Simulation of ammonia (NH) volatilization by process-oriented biogeochemical models, such as the widely used DeNitrification DeComposition (DNDC), is an imperative need to identify the best management strategies that can improve nitrogen use efficiency in crop production while alleviating environmental pollution. However, scarce validation has been impeding the applicability of the DNDC for this purpose. Using the micrometeorological or wind tunnel-based observations of NH volatilization in 44 cases with at seven nationwide field sites in China, which were cultivated with summer maize and winter wheat in calcareous soils and applied with synthetic fertilizers, the DNDC was tested, modified, and evaluated in this study.

Annual methane emissions from degraded alpine wetlands in the eastern Tibetan Plateau.

Grazing-oriented drainage of alpine/boreal wetlands has been broadly implemented to meet the increasing demand for animal products. However, the annual methane (CH) emissions from alpine fens degraded due to drainage for grazing have not been well characterized due to a lack of year-round observations. In this study, the year-round CH fluxes from a degraded alpine fen that is typical in the Tibetan Plateau (TP) were measured.

Benefits of integrated nutrient management on NO and NO mitigations in water-saving ground cover rice production systems.

To cope with challenges of food security and water scarcity in rice production, water-saving ground cover rice production systems (GCRPSs) are increasingly adopted in China and globally. Reduced soil moisture as well as increased soil aeration and temperature under GCRPSs may promote soil N transformations, and in turn give rise to environmental challenges. These include emissions of the potent greenhouse gas nitrous oxide (NO) and atmospheric pollutant nitric oxide (NO).

Net ecosystem carbon and greenhouse gas budgets in fiber and cereal cropping systems.

To assess the contributions of fiber and cereal production on climate change, the net ecosystem exchange of carbon dioxide (CO), main exchanges of non-CO carbon, and methane (CH) and nitrous oxide (NO) fluxes were continuously monitored throughout two year-round crop cycles (Y1 and Y2: 1 and 2 year-round crop cycles, respectively) using eddy covariance, biometric observation, and static chamber methods in typical cotton and wheat-maize rotational cropping systems in China. The evaluation of net ecosystem carbon budgets (NECBs: considering net ecosystem CO exchange and non-CO carbon exchanges by fertilization, seeding, and harvest) and greenhouse gas budgets (GHGBs: adding CH and NO fluxes to the NECBs based on CO equivalents) showed that the cotton cropping system persistently functioned as an intensive carbon (-1527 and -974 kg C ha yr) and greenhouse gas (GHG) source (5618 and 3591 kg CO-eq ha yr) because of the large CO emissions during the long fallow periods (5748 and 5160 kg CO ha in Y1 and Y2, respectively). The wheat-maize cropping system had high net ecosystem production (NEP) and low harvest index and therefore, served as a notable carbon sink (1461 kg C ha yr in Y2).

Increasing grassland degradation stimulates the non-growing season CO emissions from an alpine meadow on the Qinghai-Tibetan Plateau.

The alpine meadow ecosystem is one of the major vegetation biomes on the Qinghai-Tibetan Plateau, which hold substantial quantities of soil organic carbon. Pronounced grassland degradations (induced by overgrazing/climate change and further exacerbated by the subterranean rodent activities) that have widely occurred in this ecosystem may significantly alter the non-growing season carbon turnover processes such as carbon dioxide (CO) efflux, but little is known about how the non-growing season CO emissions respond to the degradation (particularly the exacerbated degradations by plateau zokor), as most previous studies have focused primarily on the growing season. In this study, the effects of four degradation levels (i.

Influences of observation method, season, soil depth, land use and management practice on soil dissolvable organic carbon concentrations: A meta-analysis.

Quantifications of soil dissolvable organic carbon concentrations, together with other relevant variables, are needed to understand the carbon biogeochemistry of terrestrial ecosystems. Soil dissolvable organic carbon can generally be grouped into two incomparable categories. One is soil extractable organic carbon (EOC), which is measured by extracting with an aqueous extractant (distilled water or a salt solution).

Annual NO emissions from conventionally grazed typical alpine grass meadows in the eastern Qinghai-Tibetan Plateau.

Annual nitrous oxide (NO) emissions from high-altitude alpine meadow grasslands have not been effectively characterized because of the scarcity of whole-year measurements. The authors performed a year-round measurement of NO fluxes from three conventionally grazed alpine meadows that represent the typical meadow landscape in the eastern Qinghai-Tibetan Plateau (QTP). The results showed that annual NO emissions averaged 0.

Urea deep placement reduces yield-scaled greenhouse gas (CH and NO) and NO emissions from a ground cover rice production system.

Ground cover rice production system (GCRPS), i.e., paddy soils being covered by thin plastic films with soil moisture being maintained nearly saturated status, is a promising technology as increased yields are achieved with less irrigation water.

Reducing NO and NO emissions while sustaining crop productivity in a Chinese vegetable-cereal double cropping system.

High nitrogen (N) inputs in Chinese vegetable and cereal productions played key roles in increasing crop yields. However, emissions of the potent greenhouse gas nitrous oxide (NO) and atmospheric pollutant nitric oxide (NO) increased too. For lowering the environmental costs of crop production, it is essential to optimize N strategies to maintain high crop productivity, while reducing the associated N losses.

Straw return reduces yield-scaled NO plus NO emissions from annual winter wheat-based cropping systems in the North China Plain.

Straw return in combination with synthetic N fertilizer is considered to be beneficial to soil fertility and crop yield. Such practice, however, can considerably modify soil microbial activity and relative C and N availability, both of which are known to regulate soil nitrous oxide (NO) and nitric oxide (NO) emissions. Minimizing these emissions per unit of crop yield is a prerequisite to minimize the environmental footprint of agricultural production and thus, a policy objective.

Improving rice production sustainability by reducing water demand and greenhouse gas emissions with biodegradable films.

In China, rice production is facing unprecedented challenges, including the increasing demand, looming water crisis and on-going climate change. Thus, producing more rice at lower environmental cost is required for future development, i.e.

[Characteristics of N2, N2O, NO, CO2 and CH4 Emissions in Anaerobic Condition from Sandy Loam Paddy Soil].

Understanding the characteristics of the production of nitrogen gases (N2, N2O and NO), CO2 and CH4 in anaerobic paddy soils is not only a prerequisite for an improved mechanistic understanding of key microbial processes involved in the production of atmospheric greenhouse gases (GHG), but might also provide the basis for designing greenhouse gas mitigation strategies. Moreover, quantifying the composition fractions of denitrification gaseous products is of key importance for improving parameterization schemes of microbial processes in process-oriented models which are increasingly used for assessing soil GHG emissions at site and national scales. In our experiments we investigated two sandy loam soils from two paddy fields.