SOUTH West farmers will welcome new trials data published by researchers at The University of Western Australia and grower groups, which suggests that light grazing of sheep on crop residues over summer has little impact on the following no-tillage crops.
Dr Ken Flower, from UWA's School of Plant Biology and Institute of Agriculture, led the study to determine if summer grazing of residue impacts the following crop yields in the no-tillage system.
Thirteen farm trial sites were used with six in WA spread across four farms at Cunderdin, Yealering, Meckering and Wickepin; along with four in northern Victoria at Banyena, Ultima, Hopetoun and Quantong; and three in southern Victoria in 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 on the following crop.
The main effect of grazing was to knock down and scatter the standing crop residues.
Crop residue is seen by many farmers 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 said this has led to the perception that no-till was 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 farmers 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 said.
"In WA, the majority of producers have adopted conservation farming methods so these results will give confidence to farmers to utilise stubble in their no-tillage systems."
The findings were published in the paper - light grazing of crop residues by sheep in a Mediterranean-type environment has little impact on following no-tillage crops - in the European Journal of Agronomy.
