Closing the Yield Gap. Measuring plant available water in Australian soils

Australian grain production is dynamic and leading edge, supplying large quantities of cereals for milling, feed and oilseed grains and pulses to the international export trade. Australia’s climate poses a challenge to the production of these introduced crops, with water being the main yield limiting influence.

Price volatility and the threat of climate instability has focused the attention of the Australian grain producer on the profitability of grain production. Understanding when, where and how soil moisture will be available to a crop has a big influence on crop choice and the nutrition required to optimise yield at harvest without eroding profitability.

With the development of technologies which can economically measure stored soil water in real time, the industry’s ability to remain internationally competitive should improve. Matching expensive inputs to available soil moisture should drive both profitability and productivity.

This report provides some insights into the techniques available to map the Plant Available Water Capacity (PAWC) of soils as well as examining some future technological opportunities which may add value to the characterisation of soils. Microwave and electro -magnetic sensing technologies promise to allow remote measurement of soil moisture in real time. Plant-based sensing techniques could aid in the understanding of critical crop stress points and the development of broad scale networking technologies will advance the ability to measure environmental variables in a cost-effective manner.