Pervasive control of soil pH on N2O and N2 emissions under anaerobic conditions from upland agricultural soils across China

Feifei Zhu1,2, Yunting Fang1,2*, Limei Zhang3, Rong Sheng4, Wenxue Wei4, Jizheng He3,5.

1 Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China, 110016,

2 Qingyuan Forest CERN, Shenyang, China, 110016

3 State Key Laboratory of Urban and Regional Ecology, Research Centre for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, China, 100085

4 Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China, 410125

5 Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia.


Soil N2 emission is an important pathway of N losses which is difficult to quantify in terms of both the magnitude and the contributions of the processes involved, yielding uncertainty in closing the N budget for agricultural systems. In this study, by adopting 15N labelling and 15N pairing technique under in vitro anaerobic conditions, the potential production rates of N2O and N2, the N2:N2O, and factors controlling denitrification, combined co-denitrification and anaerobic ammonium oxidation (anammox) were investigated for soils from 8 maize-growing regions across China from 26° N to 46° N latitude. The measured potential rates of N2O and N2 productions were 0.1 to 6.5 nmol 15N g-1 h-1 and 8.1 to 41.5 nmol 15N g-1 h-1, respectively. The dominance of N2 over N2O production resulted in N2:N2O ratios from 4 to 372 in these soils. N2O production was high at low pH soils, suggesting possible inhibition on N2O reduction. Denitrification dominated both N2O and N2 production, contributing to 85 ~ 99% of N2O, and 65 ~ 100% of N2 productions, respectively. Correlation analysis suggested that soil pH explained 30% and 46% of the variations in 15N2O and 15N2 production, respectively. Soil pH was the most important factors controlling the ratio of N2 to N2O emissions through denitrification in the studied upland agricultural soils across China, which implies that we may be able to estimate soil N2 losses from upland soils at a regional scale using N2O emission rates and soil pH.

Enhancing biological nitrogen use in crops: A translational research approach

 Manoj Prasad1*, Tirthankar Bandyopadhyay1, Rajeev Gupta2, Parveen Chhuneja3, Tina Barsby4, Alison Bentley4, Mariana Fazenda5, Ottoline Leyser5, Howard Griffiths5

1National Institute of Plant Genome Research, New Delhi, India

2International Crops Research Institute for the Semi-Arid Tropics, Telangana, India

3Punjab Agricultural University, Punjab, India

4National Institute of Agricultural Botany, United Kingdom

5University of Cambridge, United Kingdom



Optimization of biological nitrogen (N) use by crops has assumed great significance in recent years due to ever increasing fertilizer costs and severe environmental pollution due to N leaching in the soil. This is particularly relevant for developing countries where farmers have limited resources and are confronted with the need to feed an ever increasing population amidst climate change. The present study is part of the Cambridge – India Network for Translational Research in Nitrogen (CINTRIN) which aims to translate our recent understanding of developmental N use in model plants such as Arabidopsis and Brachypodium to foxtail millet, wheat, sorghum and pearl millet by screening for nitrogen insensitive (NIS) ideotypes, analysing their relative N utilization, yield potential and subsequently establish candidate genes regulating N use in them. Among the all four studied crops, foxtail millet (Setaria italica L.) is a C4 model cereal that requires very low growth inputs, and is perfectly adapted to tropical semi-arid climate. The crop has one of the highest nutritional indices for human consumption, making it one of the most suitable crops for arid and semi-arid environments.  In the present study, we employ high-throughput phenomics platforms to examine agronomically important traits in 200 genetically and geographically diverse accessions of foxtail millet and use next generation comparative genomics and bioinformatic tools to identify candidate genes/QTLs regulating N use. We also propose to compare and analyse the variation in physiological N uptake/ use and allocation to grains by using high throughput 13N/15N partitioning experiments to identify parallels with nitrogen sensitive (NS) and nitrogen insensitive (NIS) genotypes. The overall objectives of the study are to couple molecular basis of plant development to the physiology of N uptake and partitioning thereby defining new NIS ideotypes and generate valuable information on cultivar-specific N fertiliser application and offering the same directly to farmers.

Low Emission Farming – a significant step forward to improve the ecological footprint of livestock production

Michael Binder1, Christina Haasken2 and Thomas Kaufmann1,

1 Evonik Nutrition & Care GmbH, Rodenbacher Chaussee 4, 63457 Hanau/Germany,

2 Evonik Infrastructure & Technology GmbH, Rodenbacher Chaussee 4, 63457 Hanau/Germany


Animal raising and livestock production are major players in global environmental issues. Different players along the value chain must cooperate to lever existing knowledge and move towards more sustainability- based tools to measure the overall progress. The supplementation of feed with amino acids reduces feed consumption and the nitrogen content in feed, waste treatment in a biogas plant brings methane emissions to energy production, purification of methane offers new alternatives for improved energy provision and finally, specific treatment of digested residues provides new fertilizer applications. The combination of these different aspects of nutrient management, waste management, emissions management and finally fertilizer treatment enables new ecological measures to improve the nutrient cycles in livestock production especially for nitrogen compounds. Advanced LCA methodologies following the standards of DIN EN ISO 14040/44:2006 display the material flows and help to identify the losses impacting the soil and water due to eutrophication and acidification caused by nitrogen based emissions and thus, offering new mitigation options.

Fates of 15N-urea in black soil – maize system and their response to straw incorporation in northeast China: a case study

Zhi Quan1, Shanlong Li1, Feifei Zhu1, Yunting Fang1, *, Peipei Li2, Limei Zhang2, Rong Sheng3, Wenxue Wei3, Jizheng He2

1Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China

2State Key Laboratory of Urban and Regional Ecology, Research Centre for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China

3Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China



A better understanding of the fates of fertilizer N is critical to design appropriate N management strategies in intensively cultivated croplands. In this study, we evaluated the fates of 15N-urea in a field experiment on a black soil-maize system and their responses to straw incorporation in Gongzhuling, Northeast China. In order to get realistic results, we adopted the field management used by local farmers. Results showed that the crop N uptake was the main sink, recovering 52-53 % of the fertilizer N. Total 15N recoveries in plant organs followed the order: grain (27-29%) > leaf (11-12%) > stem (6%) > tassel, silks, leaf sheath, husks, etc. (5%) > root (2%) > cob (1%). Tracer N remaining in soil was the second largest sink (25-33%), and most (18-29%) was located in the ridge 0-20 cm layer (fertilized area). The total loss of fertilizer N was 13-23%. Straw incorporation increased the retention of applied fertilizer N and decreased its losses, although there was no significant difference in  plant N uptake. The contribution of fertilizer N to total  N uptake was 36-37% at the physiological maturity stage of maize. Fertilizer N was an important N source for maize growth but soil N was still the main N source. Our results indicate that Nitrogen Use Efficiency (NUE) in maize cultivation system in northeast China is not as low as that reported by many previous studies using difference or balance method. Considering the low NUE in China, our next aim is to find out which region, and which kinds of crops lowered the overall NUE in Northeast China.

Sustainability, a change of thinking

Bruce Smith

Technical Director, Eko360 Limited, PO Box 87039, Auckland 1742, New Zealand

Email:    website:


In New Zealand the use of nitrogen fertiliser has in past 25 years increased 600% while dairy production, where much of the nitrogen fertiliser is used, has increased by 270%. The unintended consequences of the excessive use of nitrogen have been a cost to the overall environment.

A paradigm shift is needed to achieve sustainable farming systems. Much of the science to support this shift has been published and it is time to dust off these research papers   re-educate and share the established knowledge with industry leaders taking responsibility.

Sustainability is a journey. It is about the People, the Planet and Profit. Practices must change to ensure they meet today’s needs while ensuring future generations have the ability to meet their needs.

Enhancing nitrogen use efficiency for Victoria and the world: a combined knowledge and innovation systems perspective

Priit Kaal1, Richard Vines2

1 DEDJTR, 1 Spring Street, Melbourne, Vic, 3000,

2 DEDJTR, 1 Spring Street, Melbourne, Vic, 3000,


Since September 2012, knowledge management specialist staff within Agriculture Victoria, (Department of Economic Development, Jobs Transport and Resources and its predecessor institutions) have been developing a number of different digital applications to foster more effective online collaborations across the public, research, private service provider, community and education sectors. Adoption of these work practices and systems, including governance systems has the potential to improve the means by which those involved in the design, deployment and monitoring of research, development and extension programs and projects can reach and engage audiences, facilitate co-design of solutions with target audiences and improve access to information and expertise.

In this paper, we explore these possibilities and articulate the benefits for adopting these innovations in line with the overarching theme of this conference: that is through the aspiration of developing solutions to enhance nitrogen use efficiency for the world. The context will be the Victorian dairy sector and in particular a project called: Manure Technologies To Drive Resource Efficiencies.  This project is situated within a policy context that intensification of all agricultural industries including the Victorian dairy industry is desirable and inevitable. This global trend towards agricultural intensification is increasing place-based conflicts involved with securing a social license to underpin a ‘right to farm’. The Victorian Government State Government in Australia is grappling with the complexity of the trade-offs between these two policy objectives.

The central claim of the paper is this. Embedding principles of good practice knowledge management into the way programs and projects are designed and managed will do much to ameliorate the tensions inherent between the policy objectives of enabling agricultural intensification and securing a social license underpinning any ‘right to farm’. The complexity associated with the trade-offs between these dual objectives involve many technical challenges. To enhance nitrogen use efficiency in the dairy sector, solutions are required across many domains –for example in facilitating the re-use of nutrients, addressing soil nutrient accumulation, reducing gaseous emissions and odour and eliminating nutrient contamination of water and air, particularly those where there are larger herds and intensive operations involved.

It will be concluded that effective knowledge management needs to address two overarching challenges (Snowden 2003). The first is to create the conditions within which innovation can emerge via effective sense-making, collaboration and innovation systems thinking that apply in both face to face and online environments. Practical examples from other sectors will be discussed to highlight how technology can be harnessed to create the conditions within which representatives of “communities of practice” (CoPs) can co-learn and co-evolve with representatives of “communities of interest” (CoIs)  in order that solutions to problems involve principles of co-design. It will be emphasised that such approaches have significant potential in the realm of manure technologies and enhancing nitrogen use efficiency. The second is to enhance the quality of decision support systems. In the case of agriculture such support systems need to be flexible and extensible enough to apply at different levels in integrated ways (i.e. across farms, catchments, industry development, community based and public policy levels). The problem at the moment is that current decision support systems do not take into account the need to integrate and value the many different types of evidence to support decision making across these different levels.

Wheat straw biochar reduces N2O emission by increasing denitrification in alkaline and acidic submerged paddy soils

Jun Shan1, Xu Zhao1, Shutan Ma1, Xiaoyuan Yan1

1 State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China, Email: or


Paddy fields are one of the most important N sinks in terrestrial ecosystems, and considerable N loss is caused by denitrification. Biochar has been recognized as useful soil amendment to paddy field in mitigating nitrous oxide (N2O) emission. However, the key mechanisms responsible for the reduced N2O emissions by biochar in paddy soils are still obscure. Here, using two paddy soils with contrasting pH, the denitrification and N2O emission were investigated in soil amened with different amounts of biochar (0%, 0.5% and 5%) via soil slurry incubation combined with N2/Ar technique. The results showed that biochar amendment significantly increased the pH values both in the alkaline and acidic soils. Biochar at 5% amendment rate significantly increased denitrification and significantly decreased N2O emission in soils. In the alkaline soil, biochar at 0.5% amendment rate significantly increased denitrification, but had no effect on N2O emission. Conversely, in the acidic soil, biochar at 0.5% amendment rate did not affect denitrification, but significantly reduced N2O emission. The N2O/(N2+N2O) ratio was significantly reduced by biochar amendment irrespective amendment rate both in alkaline and acidic soils. In the alkaline soil, biochar at 5% amendment rate significantly increased the abundance of nosZ genes, whereas biochar had no effect on the abundance of nosZ genes in the acidic soil irrespective of amendment rate. Our results suggested biochar effects in the alkaline soil were attributed to increase of denitrifying community, whereas biochar effects in the acidic soil was attributed to increase of pH.

Influence of nitrogen fertilizer and compost mix application on greenhouse gas emissions from humid subtropical soils

Anuga Liyanage12, Peter R Grace1, David W Rowlings1   Clemens Scheer1

1 Institute for Future Environments, Queensland University of Technology, 2 George Street, Brisbane, QLD 4000, Australia.     anuga.liyanage@

2 Faculty of Agriculture, University of Ruhuna, Mapalana, Kamburupitiya, 81100, Sri Lanka.


The application of organic amendments (OA) is a strategy to improve soil fertility and offset the high cost of mineral fertilizers used in agricultural systems. However, information on the interaction of OAs with synthetic fertilizers and the resulting greenhouse gas emissions from these combinations are not well understood for different soil types. A 36 day laboratory incubation experiment (3 compost x 3 N rates) was conducted to quantify soil N2O emissions along with CO2 and mineral N from subtropical soils in Gatton, Australia. Nitrous oxide emissions  decreased by 68% and 57% in  60N and 120N treatments respectively with the increase in compost applications  rates up to 30 t/ha and 60 t/ha. Adding 60 t/ha compost and 120 kg N/ha is considered  as the optimum fertilizer rate to minimize N2O and CO2 emissions from  a sub-tropical Vertosol and potentially conserving soil physical, chemical and biological properties for a sustainable crop growth.

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.

Aerated static pile composting: Characterizing the gas exhaust

Allison M. Leach1, John D. Aber1, Matt Smith1

1University of New Hampshire, 131 Main Street, 107 Nesmith Hall, Durham, NH, 03824 USA,


Aerated static pile (ASP) heat recovery composting is one strategy that can be used to promote the reuse of resources within a farm and potentially divert environmental pollution. Preliminary studies at the University of New Hampshire ASP heat recovery composting facility at an organic dairy farm have demonstrated the potential for heat recovery (Smith and Aber 2014), and such a facility could ultimately be connected to a greenhouse to heat and fertilize crops. The findings for this compost facility, which is located in the north eastern United States in a temperate region, are applicable to other livestock farms in similar climates that can collect and compost manure. The objectives of this study are to (1) present results characterizing the gas exhaust from an ASP heat recovery composting facility and (2) explore how this facility could divert ammonia, methane, and carbon dioxide emissions. For the former, preliminary results have found high concentrations of ammonia and carbon dioxide, especially early in the composting process. For the latter, the pollution diversion methods that will be explored are recovering manure for compost production, trapping composting emissions with a biofilter, and using compost gas exhaust to heat and fertilize a greenhouse.


<For the full paper, please contact Allison Leach at>