Summary

This project will scope whether rice crop water use since the end of the Millenium drought is greater than it was prior to the drought. The project aims to scope likely drivers of such changes and possible mitigation measures that could be further investigated. Increased water use in rice cropping systems is of concern across the southern rice growing irrigation districts, but particularly in the Coleambally Irrigation region.
This short term project will define the extent of the changes in rice crop water use in the southern irrigation districts with particular emphasis on Coleambally. A preliminary understanding of any environmental, agronomic and engineering changes which may have influenced a change in water use will be achieved. The results of this project will direct further targeted RD&E efforts in reducing rice crop water use across the rice industry.

Program

Rice

Research Organisation

Deakin University (a body politic and corporate established pursuant to the Deakin University Act 2009 (Vic))

Objective Summary

The principle objectives of the project are to:
• Determine the extent of any change in rice crop water use between 1995 and 2015 (i.e. pre and post the Millenium drought)
• Determine the nature and extent of any environmental, agronomic and engineering factors which may have led to a change in rice crop water use over the past 20 years
This will be achieved by meeting the following goals:
1. Locate and map areas where rice crop water use in recent (post drought) years is markedly different to what it was in the mid 90’s (pre-drought)
2. Investigate the effect of the following factors on changes in rice water use over the past 20 years:
• depth to water-table and its interaction with soil type or proximity to prior streams;
• changes in climate, particularly the influence of winter rainfall on rice fill-up, and rice season evaporation and rainfall;
• the reduction in irrigation intensity and the isolation/fragmentation of rice paddocks (“clothesline” effect)
• Changes to water metering
• Other potential factors, such as the lining of supply channels, the proximity of rice paddocks to bores, and increased groundwater usage
• Agronomic factors such as depth and duration of high water, a shift to drill sowing, or adoption of mid-season drain or delayed permanent water
3. Determine the likely key drivers behind any increased rice water usage and likely mitigation measures that could be adopted or further investigated