By Peter Hayman, South Australian Research and Development Institute (SARDI)
[Photo: Grower Colin Hutchinson makes a visual check on soil moisture as a new season approaches. Photo by Brad Collis]
Dryland crops rely on two sources of moisture; water stored in the soil prior to planting and water from the sky during crop growth.
Dr Peter Carberry, from the Agricultural Production Systems Research Unit (APSRU), says that after modelling wheat yield in many regions across Australia one of the surprising findings is how important stored soil water is to the prospects for the coming crop, not only in the northern grains belt, but also in the southern and western grains belt. He regards stored soil water as the best crop forecast.
The importance of stored soil water supports the work of Melissa Rebbeck and Jim Egan, from SARDI, who have used growers" yield and rainfall data to show the importance of early season rainfall in predicting likely crop outcomes across southern Australia.
Ms Rebbeck emphasises the need to use a combination of early season rainfall, time of sowing and seasonal outlook for risk management.
This year, many growers in the eastern part of the southern GRDC region have one of the best starts ever in terms of stored soil water, but this is tempered by availability of cash from a run of poor seasons, an ordinary price outlook and some worrying early indicators from climate science on the coming season.
As farmers make their assessment of the risks, it is worthwhile looking down by monitoring the water in the soil and then looking up by monitoring the climate outlook.
One of the best sources is the El Niño wrap-up from the Bureau of Meteorology, which is updated each fortnight.
For more information: www.bom.gov.au/climate/enso/