Carbon benefits completely offset by nitrogen fertilization induced greenhouse gas emissions in Chinese main cropping systems

Bing Gao1,2, Lilai, Xu1,2, Wei, Huang1,2, Xiaotang Ju3*, Shenghui Cui1,2*

1 Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China

2 Xiamen Key Lab of Urban Metabolism, Xiamen 361021, PR China

*Corresponding author: Shenghui Cui

Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen 361021, P.R. China.

Phone: +86-592-6190957; Fax: +86-592-6190977.


3 College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China

*Corresponding author: Xiaotang Ju and Shenghui Cui

College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.

Phone: +86-10-62732006; Fax: +86-10-62731016.



Cropland soil is recognized as a potential major contributor to mitigation global warming by using soil as a carbon sink to sequester carbon dioxide in recent years. Large amount of studies have reported that the soil organic carbon (SOC) content in Chinese cropland soil was increased. While the climate benefits of carbon sequestration in agricultural soils was offset by the N2O emissions from greater use of fertilizer and CO2-eq releases during the manufacture and distribution of the large amounts of applied fertilizer. In this study, we calculate the net GWP of the Chinese main cropping systems by reviewing the studies on soil GHG emissions, CO2-eq emissions and SOC change, to see the integrate effect of cropping systems on GHG emissions. The results showed that the Chinese main cropping systems were large source of CO2-eq, fall in a range of 2209 ± 2557 kg CO2-eq ha-1 yr-1 for MNE to 23581 ± 16925 kg CO2-eq ha-1 yr-1 for GV, following the rank of MNE < MNW < WM < SR < RR < RW < OV < DR < GV. N2O emissions, CO2-eq emissions from the manufacture and distribution of N fertilizer, power used for irrigation were the top three sources of CO2-eq, they totally contribute to 86.6–93.6% of the TPCE in five dry croplands cropping systems. But four rice-based cropping systems, CH4 emissions become one of the large contributors of TPCE except the top three sources of CO2-eq in dry land cropping systems.

Improved nitrous oxide emission factors for cattle and sheep excreta deposited in New Zealand hill country

Jiafa Luo1, Coby Hoogendoorn2, Tony van der Weerden3, Surinder Saggar4, Cecile de Klein3, Donna Giltrap4

1 AgResearch Ruakura, 10 Bisley Road, Hamilton 3240, New Zealand. Email:

2 AgResearch Grasslands, Tennent Drive, Palmerston North 4442, New Zealand

3 AgResearch Invermay, Puddle Alley, Mosgiel 9053, New Zealand

4 Landcare Research, Riddet Road, Massey University, Palmerston North 4442, New Zealand


Animal grazing behaviour in hill country results in lower inputs of animal excreta on steep slopes (> 25o) and greater nitrogen (N) deficiency compared to medium slopes (12 – 25o). Nitrous oxide (N2O) emission factors from excreta (EF3; percentage of deposited animal excreta-N emitted as N2O, %) may differ with slope. A field study was conducted in four regions of New Zealand to determine the effect of slope on the autumn-winter N2O EF3 from animal urine and dung. EF3 values at all the sites were generally very low, with most of the averages being less than 0.1%, and highly variable. The EF3 from sheep urine was significantly higher on the medium slope than on the steep slope. EF3 values for beef cattle dung tended to be higher than for sheep dung on both slope classes. There was a tendency (non-significant) for higher EF3 values for sheep dung, and higher beef cattle urine and dung, on the medium slopes than on the steep slopes.

Denitrification and N2O production in subsoil in wheat-maize rotation field in North China Plain

Yuming Zhang1, Chunsheng Hu*,1, Oene Oenema2, Bingzi Zhao3, Wenxu Dong1, Yuying Wang1 , Xiaoxin Li1

1Key Laboratory of Agricultural Water Resources, Center for Agricultural Resources Research, Institute of Genetic and Developmental Biology, the Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang, Hebei, 050021,China, Email:

2Wageningen University and Research, Alterra, Wageningen, The Netherlands

3Institute of Soil Science, Chinese Academy of Sciences, Nanjing , Jiangsu, 210008, China


Excessive application of fertilizer nitrogen (N) in crop production systems in North China Plain has resulted in the accumulation of nitrate (NO3) in subsoil and groundwater. Denitrification is a possible pathway for removal of accumulated nitrate in subsoil, but is often neglected and/or regarded as unimportant because of the difficulty of measuring denitrification in the subsoil.

The aim of the study reported here is to quantify the seasonal variations in denitrification activity in a 190cm deep soil profiled under a wheat-maize double cropping system as a function of N fertilizer application. The study was conducted at the Luancheng agro-ecosystem experimental station, CAS, in 2009-2010. The N fertilizer treatments included 0 (CK), 450 (N1) and 750 (N2) kg N ha-1 year-1, in triplicate. Soil cores were taken by the Geoprobe machine and incubated using acetylene inhibition technique.

Denitrification rates in the 1.9 m deep soil profile showed the commonly observed responses to N fertilizer application, irrigation and rainfall, leading to strong a temporal variability. Nitrogen losses through denitrification were significantly higher (a factor of 2.0 to 2.7) in the maize growing season than in the wheat season, likely because of the more wet and warm weather conditions in the maize growing season. On average, only 26% of total denitrification activity in the 190 cm deep soil profiled occurred in the top soil (0-15 cm); 33% occurred in the 15 to 90 cm soil layer and 41% in the 90 to 190 cm soil layer in CK. The contribution of the top soil (0-15 cm) increased to ~ 45% and that of the subsoil (90-190 cm) decreased to ~ 28%, when the N fertilizer application increased to 750 kg per ha per year. The total amount of N lost via denitrification was 6, 15 and 28 kg N ha-1yr-1 in the CK, N1 and N2 treatments, respectively.

In conclusion, the subsoil (15-190 cm) was a large contributor to N losses via denitrification, although the total N losses via denitrification were only in the range of 1 to 6% of total N fertilizer application. Further studies should try to understand the mechanism and controlling factors of denitrification in the low-carbon subsoil.

Impacts of land use and land cover changes on nitrous oxide emissions in the Brazilian semiarid

Kelly Ribeiro1, Eráclito Rodrigues de Sousa-Neto1, Paulo José Duarte-Neto2, Jean Pierre Henry Baulbaud Ometto1, Rômulo Menezes3, Willian José Ferreira1.

1Centro de Ciências do Sistema Terrestre – CCST, Instituto Nacional de Pesquisas Espaciais – INPE, São José dos Campos, SP, Brazil

2Departamento de Estatística e Informática, Universidade Federal Rural de Pernambuco – UFRPE, Recife, PE, Brazil

3Universidade Federal de Pernambuco – UFPE, Recife, PE, Brazil


Arid and semiarid lands cover about 30% of the earth surface and may be increasing due to global change. Furthermore, semiarid zones are poorly understood and their contribution to the budges of atmospheric gases such as nitrogen oxides are extremely sparse. In Brazil, semiarid lands totalize 980,133 km2, which has a population of ~22.6 million inhabitants. This semiarid region undergoes natural lengthy periods of drought that cause losses in crop and livestock productivity, having severe impact on the population. Due to the regions vulnerability to climate change, livestock has emerged as the main livelihood of the rural population, being the precursor of the replacement of native vegetation by grazing areas. This study aimed to measure nitrous oxide emissions (N2O) from two different soil covers: a native forest and a pasture in the municipality of São João, Pernambuco State, in the years 2013 and 2014. N2O measurements were made by using static chamber techniques. Nitrous oxide emissions ranged from -1.0 to 4.2 mg m-2 d-1 and -1.22 to 3.4 mg m-2 d-1 in the pasture and native forest, respectively, and they did not significantly differ from each other. Emissions were significantly higher during dry seasons and correlated with high temperatures. In this study, soil gas fluxes seemed to be more influenced by climatic and edaphic conditions than by soil cover in the semiarid regions.

Modeling ammonia volatilization over Chinese croplands

Ziyin Shang1, Feng Zhou1, Shuoshuo Gao 1, Yan Bo1, Philippe Ciais 2, Kentaro Hayashi 3, James Galloway 4, Dong-Gill Kim 5, Changliang Yang 6, Shiyu Li 6, Bin Liu 6

1 Sino-France Institute of Earth Systems Science, Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, P.R. China, Email:

2Laboratoire des Sciences du Climat et de l’Environnement, CEA CNRS UVSQ, 91191 Gif-sur-Yvette, France

3Carbon and Nutrient Cycles Division, National Institute for Agro-Environmental Sciences, 3-1-3, Kannondai, Tsukuba, Ibaraki 305-8604, Japan

4Environmental Sciences Department, University of Virginia, Charlottesville, Virginia 22904, USA

5Wondo Genet College of Forestry and Natural Resources, Hawassa University, PO. Box 128, Shashemene, Ethiopia

6Research Institute of Engineering Technology, Yunnan University, Kunming, 650091, P.R. China


Ammonia (NH3) released to the atmosphere leads to a cascade of impacts on the environment, yet estimation of NH3 volatilization from cropland soils (VNH3) in a broad spatial scale is still quite uncertain in China. This mainly stems from non-linear relationships between VNH3 and relevant factors. Based on 495 site-years of measurements at 78 sites across Chinese croplands, we developed a nonlinear Bayesian Tree Regression model to determine how environmental factors modulate the local derivative of VNH3 to nitrogen application rates (Nrate) (VR, %). VNH3-Nrate relationship was non-linear. VR of upland soils and paddy soils depended primarily on local water input and Nrate, respectively. Our model demonstrated good reproductions of VNH3 compared to previous models, i.e., more than 91% of the observed VR variance at sites in China and 79% of those at validation sites outside China. The observed spatial pattern of VNH3 in China agreed well with satellite-based estimates of NH3 column concentrations. The average VRs in China derived from our model were 14.8 ± 2.9% and 11.8 ± 2.0% for upland soils and paddy soils, respectively. The estimated annual NH3 emission in China (3.96 ±0.76 TgNH3·yr-1) was 40% greater than that based on the IPCC Tier 1 guideline.

Improved reduced nitrogen deposition estimates in the United States: Spatial variability of ammonia

Melissa Puchalski1, Donna Schwede2, John T. Walker3, Kristen Foley2, Gary Lear1, Gregory Beachley1, Richard Haeuber1

1 US Environmental Protection Agency, Office of Air Programs, 1200 Pennsylvania Ave NW, Washington D.C. 20460,, Email:

2US Environmental Protection Agency, National Exposure Research Laboratory, 109 T.W. Alexander Dr, Research Triangle Park, N.C. 27709

3US Environmental Protection Agency, National Risk Management Research Laboratory, 109 T.W. Alexander Dr, Research Triangle Park, N.C. 27709


The Clean Air Status and Trends Network (CASTNET) is the only long-term monitoring network in the United States that provides estimates of dry deposition for sulfur and nitrogen species. CASTNET measures ambient concentrations that are combined with modeled deposition velocities to estimate dry deposition at more than 90 sites. Until recently, concentrations of NH3 were not routinely measured at CASTNET sites, resulting in a significant gap in the total nitrogen budget. Between 2008 and 2015, more than 60 National Atmospheric Deposition Program (NADP) Ammonia Monitoring Network (AMoN) sites were deployed at CASTNET sites, providing ambient NH3 concentrations.

Estimates of total (wet + dry) deposition are provided by combining measured ambient concentrations and wet deposition fluxes with modeled estimates of dry deposition velocities and fluxes for unmeasured species (Schwede and Lear, 2015). The NADP’s total deposition (TDEP) hybrid method combines data from several routine monitoring networks and the Community Multi-scale Air Quality (CMAQ) model. The deposition fluxes are interpolated to create a continuous surface using inverse distance weighting (Figure 1). NH3 may not be well characterized in the model and influences from emissions sources may impact the radius of influence between sites. This paper describes results from an NH3 spatial variability study designed to improve the spatial interpolation methods used in the TDEP maps. During this study, supplemental passive NH3 monitoring sites were randomly distributed around the Bondville, IL (IL11) and Fort Collins, CO (CO13) AMoN sites for one year. Results from this analysis will improve future gridded total deposition estimates.

Advances in Critical Loads Science and Application in the United States

Jennifer Phelan1, Jason Lynch2, Claire O’Dea3, Tonnie Cummings4, and Rick Haeuber2

1 NADP-CLAD, University of Illinois, 2204 Griffith Drive, Champaign, Illinois, 61820,,

2 U.S. EPA, 1200 Pennsylvania Avenue NW, Washington, DC, 20460

3 U.S. Forest Service, 1400 Independence Ave, SW, #1121, Washington, DC, 20250

4 U.S. National Park Service, Pacific West Region, 612 E. Reserve Street, Vancouver, Washington, 98661


The objectives of this poster are to describe recent advances in critical loads science and application in the United States (U.S.), including critical load definitions, the National Critical Load Database (NCLD), and critical load maps.   A series of critical load maps based on NCLD data are presented for the U.S.  New critical load research, new and future products, and future directions for critical loads science and application are also outlined.

A Sequential Diffusion Method for 15N Natural Abundance Measurement of Ammonium, Nitrate and Total Dissolved Nitrogen in Water Samples

Haruka Kiba1, Fujio Hyodo2, Yuichi Asano3, Morihiro Maeda1.

1 Okayama University, Graduate School of Environmental and Life Science, 3-1-1 Tsushima-Naka, Okayama 700-8530, Japan


2 Okayama University, Research Core for Interdisciplinary Science, 3-1-1 Tsushima-Naka, Okayama 700-8530, Japan

3Oyo Corporation, 2-907 Seko-Higashi, Moriyama-Ku, Nagoya 463-8541, Japan


Natural abundance of nitrogen-15 (δ15N) is a useful tool to estimate sources of nitrogen (N). The objective of the study was to clarify practical conditions of a sequential diffusion-based method for 15N natural abundance of inorganic N and total dissolved N (TDN) with relatively high concentration. We tested the sequential diffusion method at 40ºC for 24 hours for recovery of NH4-N and NO3-N (0–40 mg L-1) and for that of TDN (0–4 mg L-1). Results showed that the complete recovery was achieved for inorganic N with 0.3–30 mg L-1 and for TDN 0–3 mg L-1. Furthermore, recovery rates for TDN declined when the amount of N exceeded 120 μg N. The time required for N recovery can be shortened to 24 hours by increasing temperature to 40ºC. No discrimination of 15N occurred during the whole process under the above conditions. In conclusion, the sequential diffusion method for 15N natural abundance measurement can be applied to water samples including 0.2–20 mg L-1 for NH4-N or NO3-N, and 0.25–3 mg L-1 for TDN. The volume for TDN recovery must be adjusted so that amount of TDN in solution is less than 90 μg N.

Changes in 16S rRNA bacterial community structures after C and N additions – comparison of organic farmed and conventionally farmed soils

Misato TODA1, Yoshitaka UCHIDA2

1 Graduate School of Agriculture, Hokkaido University, Kita9 Nishi9 Kita-ku, Sapporo, Hokkaido, 0608589, Japan.,

2 Research Faculty of Agriculture, Hokkaido University, Kita9 Nishi9 Kita-ku, Sapporo, Hokkaido, 0608589, Japan.


The use of legumes has received heightened interest as an alternative to chemical fertilizers in recent years. It adds not only nitrogen (N) but also carbon (C) to soils thus it might influence the soil microbial community structures. Considering that microorganisms play a key role in N dynamics, it is important to understand the relationship between the soil microbial structure and soil N dynamics, in relation to the use of legumes. Thus, we aimed to evaluate the relationship between the long-term legume application and soil microbial community structures. Also we aimed to investigate the relationship between the microbial communities and the soils’ N immobilization potential, because N immobilization by microbes often competes with plants in terms of N availability in soils. We compared a soil with the history of the use of green manure (hairy vetch, HV) and a soil with the history of the use of N chemical fertilizer (CF). First, we investigated the microbial communities using a colony counting method and a 16S rRNA gene analysis. Then we conducted an incubation experiment where we added C and N source into soils and measured N immobilization potentials. Bacterial community structures were analyzed to investigate the interaction between N immobilization potentials and bacterial community structures. Our results showed that there was a significant difference in microbial community structures for the two soils before the addition of C and N. However, no significant difference was detected on N immobilization potential during the incubation. Moreover, the difference between the bacterial community structures in the two soils became smaller as the incubation progressed, within 14 days. According to these results, it is indicated that microbial community structures were clearly influenced by the use of hairy vetch but with added C and N, the community structure differences due to the use of hairy vetch might disappear.

Estimation of N2 and N2O production in a eutrophic river using a newly developed gas trap device

Yan Gao a, 1, Zhenhua Zhang a, Xinhong Liu a, Neng Yi a, Li Zhang a, Yan Wang a, Shaohua Yana

aInstitute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, 50 Zhongling Street, Nanjing 210014, China;


Biogenic gas production in a eutrophic pond located in the subtropical climate zone of China was quantified using a newly developed gas-trapping device. This device allows for a vertically resolved collection and subsequent analysis of biogenic gases (N2, O2, N2O and CH4). Determining the vertical structure of gas production is especially relevant in stratified water bodies as it allows to link the stratification of physicochemical parameters with the gases produced. The investigated pond exhibited strong thermal stratification in temperature, DO, pH, nutrients and Chlo-α during summer and autumn, but not in winter. Gas production was greatest at the sediment-water interface and in the surface layer and small in the middle layer. Gases produced at the surface were mainly N2 and O2, whereas the latter is likely to stem from photosynthetic activity as gas production followed a diurnal cycle. At the sediment-water interface, the collected gas was mainly composed of N2 and CH4. Our results highlight the vertical heterogeneity of gas production and underline the value of vertically-resolved sampling which is made possible with the presented gas-trapping device.