Cropping: John Stevenson has researched ways to close the gap between potential grain yield and soil Plant Available Water Capacity (PAWC). Photo: Cindy Benjamin

World leaders in soil water, with room to improve

Growers and advisors at the Grains Research Development Corporation (GRDC) Research Update in Wagga Wagga this February will have the opportunity to gain insight into differences around the world when it comes to soil water use and measurement.

Growers and advisors at the Grains Research Development Corporation (GRDC) Research Update in Wagga Wagga this February will have the opportunity to gain insight into differences around the world when it comes to soil water use and measurement.

Speaking on day one of the Update (February 13), Nuffield Scholar and manager with Warakirri Cropping business John Stevenson, says Australia is a world leader when it comes our ability to produce quality crops in a challenging climate.

Mr Stevenson’s Nuffield study investigated ways to close the gap between potential grain yield and soil Plant Available Water Capacity (PAWC), with a focus on boosting productivity from sustainable dryland cropping systems.

 “A yield gap between crop production and available soil moisture exists globally, with Australian dryland growers very efficient compared to our overseas equivalents, but there is further room to improve,” he said.

“We need to do more to visualise our soils in three dimensions to allow us to address limitations in the root zone of crops and optimise inputs to match our soils productive capacity.”

Mr Stevenson said of the technologies he saw overseas, those now in use in Israel have exciting potential for adaption to Australian farms. 

“Whole of farm wireless connectivity and plant growth tracking are systems now helping Israeli growers to maximise production. Long Range Wireless Area Networks (LORAWAN) allow remote monitoring of thousands of in-field sensors at very low cost,” he said.

“Another exciting prospective technique was the use of an in-field penetrometer to measure near infra-red (NIR) reflectance/adsorption, which was developed by Texas A&M University in collaboration with Sydney University.

“This process allowed growers to get a three-dimensional view of their soil without the disruption of excavation and this technology has now been commercialised.”

Mr Stevenson said EM38 mapping was well regarded although not widely adopted around the globe as a means of differentiating soil zones based on their Electrical Conductivity (EC).

“EM38 systems are evolving and products such as the Austrian ‘Soil Mapper’ are able to be installed to machinery as it passes over a field, which allows for the possibility of building relative soil water maps in real time by measuring soil water at intervals throughout the season.

“This data could potentially apply nitrogen fertilisers at variable rates in real time to match soil water to productive capacity,” he said.

Mr Stevenson will be speaking on day one of the two-day GRDC Research Update at Wagga Wagga, which is being held on February 13 and 14, at Joyes Hall at Charles Sturt University.

Other speakers include Greg Rebetzke of CSIRO on breeding wheat to increase competitiveness against weeds, Felicity Harris from the Department of Primary Industries (DPI) New South Wales on getting the best performance from barley, and Dale Grey from Agriculture Victoria on the facts and fiction of weather and seasonal forecasting.

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