The research questions

• How do rice yields, profitability and on farm water balance components of Water Saving Irrigation (WSI) methods (such as alternate wetting and drying (AWD), partially rain-fed (PRF), flush irrigation (FI)) perform? What is the performance in field conditions of aerobic rice compared with continuously flooded rice.
• What are the impacts of alternative water-saving management practices at farm, irrigation system and sub-basin levels? What are the best options for improving river water flows and minimizing adverse economic and environmental impacts of these irrigation areas?
• How effective are the policies, institutions, management practices and infrastructure that are currently in place for water allocation and utilization? What are the incentives to adopt water-saving practices at farm and system levels?
• What areas are best suited for the promotion of selected water-saving technologies determined by this research and what is the best way to promote these technologies and policies in those regions?

Objective

To promote water management techniques in rice-based irrigation systems that sustain the environment and allow the crop production to be maintained or increased in the face of growing demands for competing uses of water.

Methods

• The research was carried out at three locations with contrasting soil-hydrological and institutional environments
  1. The Zhanghe Irrigation System (ZIS) in the Yangtze River basin
  2. The Liuyuankuo Irrigation System (LIS) in the physically water-scarce Yellow River Basin
  3. The Murrumbidgee Irrigation Area (MIA) in NSW, Australia; a major sub-catchment of the Murray Darling Basin.
• Controlled field experiments, farm surveys and socioeconomic surveys were carried out at the field level at the selected sites for both aerobic and flooded rice systems.
• Field results were then tested and confirmed by simulations using ORYZA2000 crop model, which was used to assess the effect of AWD and aerobic rice under different hydrological conditions and water management scenarios.
• Outputs from ORYZA2000 were used in the regional models to investigate the effects of AWD on system level hydrology and water productivity.
• The water balance was studied at farm, meso scale and sub-basin level using field data collection and analysis. MODFLOW and VENSIM models were used in a hydrologic-economic analysis, at Liuyuankuo, of different scenarios for water savings. These scenarios consisted of different combinations of
  1. Canal lining
  2. Ground water development (GW) in the northern part (above the railway line, ARL) of LIS
  3. Distributing surface water to below the railway line. MODFLOW, VENSIM and SWAP models were used to quantify water saving at farm and system-level in the Murrumbidgee catchment. Simulations using an IWMI developed model, OASIS, were used to investigate the relative role of AWD, small storage, and water allocation practices, and to help managers understand the implications of various water savings options at Zhanghe.
• Information on policies and institutions was gathered based on interviews at different levels - from policy makers, irrigation system managers, village leaders and farmers. the surveys picked up relevant information.

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