Decision tools helping growers test the waters

Author: Bill Ryan | Date: 26 Aug 2014

Image of Bill Ryan, GRDC western regional panel member

Water is the input that limits yields the most in Western Australian cropping systems.

So the key for growers in any year – wet or dry – is to extract maximise value from it. To do this, they need to make sure that other inputs, such as nitrogen, are at compatible levels.

The Grains Research and Development Corporation (GRDC) has invested significant funding into developing the modelling technology that is giving growers greater confidence in crop decision making, based on soil water and other factors.

The decision support tool Yield Prophet® is the front end that everyone sees, but behind it sits the Agricultural Production Systems simulator model (APSIM) - the most sophisticated crop yield prediction system in Australia.

APSIM was developed by CSIRO, the University of Queensland and the Queensland Department of Agriculture, Fisheries and Forestry, with GRDC support. It is designed to provide growers and advisers with online, real-time, paddock-specific information about the crop during the growing season.

At the other end of the research spectrum, the GRDC is funding some of WA’s Yield Prophet® sites, through its Regional Cropping Solutions Network (RCSN) initiative, and installing soil moisture probes at some of them.

The rationale behind the GRDC’s support for both the modelling and field work is that cropping systems are complex and it can be difficult for growers to integrate all the information available to them.

APSIM and Yield Prophet® integrate a lot of that information and give growers an indication of possible yields, including the impact of applying additional inputs such as nitrogen.

Mid-season analysis by Precision Agronomics Australia this year – conducted under the GRDC RCSN project - showed that nitrogen ‘top ups’ could have variable yield benefits in WA depending on location – ranging from nil to more than 0.5 tonnes per hectare.

This sort of information enables growers to manage risk and clarify the likely yield response from applying additional nitrogen.

Growers inherently understand what sort of a season they’re having, but decision support tools such as Yield Prophet® allow them to put numbers around it, giving them more confidence in their management decisions.

For more information about Yield Prophet®, visit

Information from the RCSN sites – relating to plant available water versus growing season rainfall – can be found at the ‘Probes and Prophets’ webpage, available at by clicking on ‘services’, then ‘moisture probes and yield prophet’.

Full soil moisture probe datasets, showing variations at 10cm depth increments, rainfall, temperature and humidity can also be viewed by entering the username: RCSN and password: grdc (both case sensitive) into the Outpost Central login portal at the bottom of the ‘Probes and Prophets’ webpage.

The DAFWA statistical seasonal forecasting service AgSeasons is available at – click on Climate, land and water then Climate and weather.


Caption: GRDC western panellist Bill Ryan says decision support tools such as Yield Prophet give growers greater confidence in their management decisions.

GRDC Project Code CUR00012

Region West, North