Improving the management of water and nitrogen fertiliser for agricultural profitability, water quality and reduced nitrous oxide emissions in China and Australia

Wheat and maize are important crops in China's western provinces which are a high priority for Australian assistance. Crop production is limited by the availability of water and nitrogen (N), yet where irrigation and N fertiliser are applied they are used wastefully. The low efficiency of water and N use in irrigated cropping results in lowered incomes for farmers and impaired water quality. Inefficient use of N fertiliser and excessive irrigation directly leads to emission of the greenhouse gas (GHG) nitrous oxide (N₂O). Volatilisation of ammonia (NH₃) is often the major pathway of N loss and contributes indirectly, after NH₃ return to the soil, to N₂O emissions. Excess soil nitrate (NO₃^-) is leached to groundwater. An earlier ACIAR project developed a GIS-based Water and Nitrogen Management Model (WNMM) for irrigated crops on the North China Plain, which has facilitated improved N fertiliser use, and has increased awareness of the need to improve water management in Henan and Hebei Provinces. The project contributed to changes in fertiliser practices that have increased farmers' incomes whilst reducing off-site losses of N.

This new project will apply a similar approach to western areas where significant gains in farm profitability and environmental management can be achieved. The focus will be on developing better practices for irrigating and fertilising maize and wheat grown in Shanxi Province. Shanxi Provincial agricultural agencies have an ongoing commitment to improve fertiliser use, water use and water quality. The project objectives are also consistent with the objectives of two AusAid projects, the Alxa League Environmental Rehabilitation and Management Project in the western part of the Inner Mongolia Autonomous Region (IMAR) and Water and Agricultural Management in Hebei Province (WAMH). The WNMM model and the derived decision support system (DSS) will be used in the selected irrigated cropping areas in the two AusAid projects to strengthen the dissemination components. In IMAR, in particular, the AusAID project on irrigated cropping at groundwater oases has found that water and N management is poor, and that NO₃^- is accumulating in groundwater.

The overall objective of the project is to improve the management of water and N fertiliser to increase farm incomes, improve environmental quality and reduce N₂O emissions from agriculture. The systems to be addressed are irrigated maize and wheat farms in the western Yellow River Basin of northern China, and intensive irrigated pasture and maize, and rain-fed wheat in Australia. Measured inputs and simulated outputs of the model will be linked to economic data to analyse the financial consequences of management and market conditions. The financial outcomes will be evaluated in the context of current government policies and social factors in farming communities. An agricultural decision support tool (ADST) will be developed, which will provide the Shanxi agricultural advisory agencies, and the AusAid project teams, with best management practices (BMPs) that farmers can use to improve water and N management. The ADST will allow policy makers to assess the environmental consequences of farming practices, especially with respect to NO₃^- contamination of groundwater and the release of N₂O, and how practices might be changed to improve the profitability of irrigated agriculture and minimise adverse environmental impacts.

Adoption will be promoted through field experiments at demonstration sites in Shanxi Province and through the AusAid projects. Field work will be conducted in partnership with the Shanxi Institute of Soil and Fertiliser, Chinese Academy of Sciences (CAS) and Chinese Academy of Agricultural Sciences (CAAS). Policy recommendations from this research will inform existing and future national and provincial government plans for improved efficiency of water and fertiliser use and resource sustainability. An advisory panel will be formed to provide consistent advice to the agencies in Shanxi and AusAid teams, and to promote findings to government decision-makers.

The project is complemented by studies on irrigated crops and pastures in northernVictoria and in the Riverina of New South Wales, and on rain-fed wheat in Western Australia. This will reinforce research on soil water and N, and strengthen the development of spatially-referenced models for regional water, N and P balances, and GHG emissions from agriculture. The project has significant components on quantifying N₂O emissions, and developing and implementing mitigation strategies, supported by the Australian Greenhouse Office (AGO), Chinese government, CAS and CAAS through the Australia-China Joint Declaration on Bilateral Cooperation on Climate Change.

Project Objectives:

The overall objective of the project is to improve the management of water and N fertiliser to increase farm incomes, improve environmental quality and reduce N₂O emissions from agriculture. The systems to be studied are irrigated maize and wheat cropping systems and intensive vegetable farms in the western Yellow River Basin of northern China, and intensive irrigated pasture and maize, and rain-fed wheat systems in Australia. The project has two specific objectives.

Objective 1: To introduce best management practices for water and N management that take into account social and economic aspects, N₂O emission and climate variability. The activities to achieve this are;

• Adapt and calibrate the WNMM model to incorporate social and economic aspects affecting the choice of water and N management practices by farmers for irrigated crops in the focus areas in Shanxi, and apply the model to dissemination areas in IMAR and Hebei.
• Develop sustainable management practices to minimise N₂O emissions by more reliable measurement techniques and improved modelling.
• Evaluate BMPs on-farm in the focus areas.
• Develop practical tools to deliver tested BMPs.
• Further develop WNMM to account for the impacts of climate variability and its performance in Australian conditions.

Objective 2: To develop policy options that lead to more efficient use of water and N fertilisers, and the reduction of N₂O emissions. The activities to achieve this are;

• Survey farmers to determine the sensitivity of farmers to changes of the price of water and N fertiliser.
• Use the spatially-referenced decision support tool to develop the policy options and test these with farmers and regulators.

The project will run for 4 years, commencing on April 1st 2005 and finishing on March 31st 2009.

Total project budget: $5.0 million (AUS$) ($2.58 million cash and $ 2.52 million in-kind contribution)

Funded by: Australian Center International Agricultural Research (ACIAR), Australian Greenhouse Office (AGO), University of Melbourne (UM), Chinese Academy of Sciences (CAS), Chinese Academy of Agricultural Science (CAAS) and Shanxi Academy of Agricultural Science (SAAS) and China Agricultural University.

Research Team (Australia): Dr Deli Chen (Overall Project leader, Project leader Australia, UM), Dr Robert Edis (UM), Dr Brian Davidson (UM), Dr Yong Li (UM), Emeritus Professor Robert White (UM), Dr Tony Weatherley (UM), Dr. Richard Eckard (DSE Victoria), Dr Tom Denmaed (Honorary Fellow, UM), Mr Ron Teo (UM).

Research Team (China): Prof Zhu Zhaoliang (Project Leader China, CAS Institute of Soil Science at Nanjing), Prof Chen Mingchang (Team leader, Shanxi Academy of Agricultural Science-SAAS), Prof Zhang Qiang and Prof Jiao Xiaoyan (SAAS), Prof Lin Erda (Chinese Academy of Agricultural Sciences-CAAS), Prof Zheng Xunhua (CAS Institute of Atmospheric Physics, Beijing), Prof Li Baoguo and Prof Huang Yuanfang (Chinese Agricultural University-CAU).

Contact for further information: Dr Deli Chen, delichen@unimelb.edu.au