Dr Ken Flower says sheep can lightly graze stubble over summer without compromising no-till systems.
PHOTO: Evan Collis
Research by the University of Western Australia (UWA) and grower groups has found that light grazing of sheep on crop residues over summer has little impact on the following no-till crops.
Dr Ken Flower from UWA’s School of Plant Biology and Institute of Agriculture led the study to see if summer grazing of residue had an impact on the following crop yields in the no-till system.
Thirteen farm trial sites were used: six in WA spread across four farms at Cunderdin, Yealering, Meckering and Wickepin; four in northern Victoria at Banyena, Ultima, Hopetoun and Quantong; and three in southern Victoria at Inverleigh, Lake Bolac and Werneth.
The results showed that light grazing of sheep on crop residues had no significant effect on the amount of residue, soil properties, soil water, weeds or yield in the following crop. The main effect of grazing was to knock down and scatter the standing crop residues.
Crop residue is seen by many growers as a valuable livestock feed; however, soil cover provided by crop residues is a key component of conservation agriculture for maintaining favourable soil structure and high yields.
Dr Flower says this has led to the perception that no-till is incompatible with livestock grazing of residue due to the effect on soil cover and perceived problems including trampling, compaction and reduced infiltration, weed seed burial and transport and erosion.
“Most growers still consider it important to maintain livestock for a more sustainable and diverse system, as a result of reduced economic risk and greater flexibility in weed control with the use of pastures,” Dr Flower says.
The collaborating groups were the Western Australian No-tillage Farmers Association, the Facey Group, the Birchip Cropping Group, CSIRO, Falkiner Ag Pty Ltd, Mallee Focus and Nicon Rural Services Pty Ltd.
The research was funded by the GRDC and the Australian Government’s Caring for our Country initiative through the Grain and Graze 2 project, with assistance from the Australian Centre for International Agricultural Research.
Dr Ken Flower
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