Get to know your soil moisture
Understanding the current soil moisture levels within each paddock is paramount leading into summer crop planting and help is at hand for northern region growers facing a dry start to the season.
A new research paper presented at the Grains Research and Development Corporation (GRDC) Updates provides a comprehensive outline of the tools available to cost-effectively measure soil water leading into summer crop planting.
However CSIRO researcher Neal Dalgliesh warns soil water can be effectively monitored to assist managers in crop decision support but given the inherent variability of northern cropping soils and currently available sensor technologies it is difficult to achieve high levels of accuracy.
“Given the vagaries of the system, there are a number of technologies which will provide a level of information useful in decision support that aren’t cost-prohibitive,” Mr Dalgliesh says.
“Devices include in-situ devices that have relatively small zones of measurement and rely on good soil/sensor contact to measure soil water are at a disadvantage in shrink/swell soils where soil movement and cracking are typical.
“In comparison, the use of a portable EMI device to measure bulk electrical conductivity and calculate soil water has a number of advantages.”
He says EMI is quick, allowing for greater replication, measures the soil moisture of a large volume of soil (to 150 centimetres depth), is not affected by cracking or soil movement and does not require installation of an access tube thus making it available for use on multiple paddocks.
The downsides are that it is unsuitable for use in saline soils and does not apportion soil water to particular layers within the soil profile, he says.
To download the GRDC Update paper detailing soil moisture measurement, visit www.grdc.com.au/GRDC-UpdatePaper-Dalgliesh2013-MeasuringSoilWater.
For more information on GRDC-supported research, visit www.grdc.com.au.
Senior Consultant, Cox Inall Communications
07 4927 0805
GRDC Project Code CSA00023