The challenge
Water limits agricultural productivity
It is widely accepted that water is the most universally limiting factor in Australian agricultural production systems. Over recent years growers across most of Australia have suffered from unreliable rainfall – too little, too early or too late.
Our response
The National WUE Initiative is born
With the aim of improving water use efficiency (WUE) of grain-based farming systems the Grains Research and Development Corporation (GRDC) started a research initiative across the southern and western regions. The Initiative's goal was to achieve a 10 per cent increase in the WUE of their farming systems.
CSIRO provided farming systems science support and a national co-ordination and communication role to the network of 16 regional grower groups involved in the National Water Use Efficiency (WUE) Initiative.
CSIRO's water use efficiency research
Some of our research projects in water use efficiency include:
- developing an understanding of the limiting factors to obtaining a maximum WUE
- understanding what management practices can increase WUE
- studying the plant available water capacity of different soils
- working with landholders to provide them with tools to identify poor performing patches in paddocks and then assess possible management changes to profitably manage these areas
- reducing risk by modelling practical strategies that farmers can implement, such as optimal plant density, early sowing and ensuring there is adequate nitrogen in order to maximise WUE and predict potential grain yield
- studying root vigour and the ability of roots to utilise soil water stored at depth
- assessing productivity, risk and WUE associated with continuous cereals and rotations, including break crops across a range of soil types in the Mallee regions.
The results
WUE Initiative research findings
Water availability can vary as a result of environmental circumstances, such as rainfall, and through management practices, such as nutrient supply and sowing time, or from use of different species or cultivars.
CSIRO scientists studied the factors that influence WUE and investigated what management practices led to an increase in WUE. The research also investigated at the capacity of the whole farm, rather than a single crop or paddock and consequently assessed the production and profit potential and the associated risks.
The WUE Initiative demonstrated ways in which growers across all regions could increase their long-term average winter crop yields of winter grain crops, including barely and canola, without increasing input costs. Improved summer fallow management, including weed management and stubble retention can lead to a 60 per cent increase in grain yield. The use of a vetch (legume) break crop following two consecutive grain crops can lead to an increase of between 16 and 83 per cent. The results also revealed that by matching nitrogen supply to the soil type it is possible to achieve an increase of up to 91 per cent. These optimised practices allow farms build drought resilience into their cropping cycles, and boost productivity.”
Tools that support Water Use Efficiency research
Crop models developed by CSIRO and partners have been used extensively throughout the WUE initiative to demonstrate the impact of management changes in trials and in the paddock.
These include:
- The Agricultural Production Systems Simulator (APSIM™)
- Yield Prophet™
This work is captured in greater detail in a special issue of GRDC's Ground cover magazine.