Michael Moodie¹, Zac Economou², Mark Trotter², Alison Frischke³
¹Mallee Sustainable Farming, VIC, ²University of New England, NSW, ³Birchip Cropping Group, VIC
Livestock are an integral component of Mallee farming systems, however, the integration of cropping and grazing remains a major management challenge. In these mixed farming systems, livestock and cropping enterprises normally occupy the same land, where livestock graze the stubbles of winter crops over the summer fallow period and paddocks are rotated between crops and pastures. Consequently, farm infrastructure is not optimised for grazing enterprises and paddock sizes tend to be large to promote efficient cropping practices.
Mallee paddocks are also characterised by extreme soil variability and within a short distance the soil types can changes from deep sands to clay loams. These variable soil types support different levels of feed availability and have different susceptibilities to soil erosion. As a consequence, farmers report that they are not able to fully utilise all of the feed on offer within a paddock without reducing groundcover below critical levels. Furthermore, in situations where farmers are forced to extract maximum productivity from grazing these paddocks, soil erosion often results on the most vulnerable soil types, such as sand dunes.
In low rainfall farming systems such which have substantial within paddock soil variation such as the Mallee, there is potential for in-paddock spatial grazing to greatly improve both cropping and livestock productivity. As well as increasing grazing, utilisation of crop residues while reducing the risk of overgrazing in parts of the paddock, spatial grazing could also make crop grazing more profitable and less risky by targeting grazing to areas where the risk of subsequent grain yield loss is lowest.
Technology such as portable fencing systems and virtual fencing potentially offer a solution to the issue of grazing large Mallee paddocks with high soil variability. To gain insight into the perceived value of virtual fencing among crop-livestock farmers, a survey of 573 Australian grain growers with livestock was conducted across 12 major southern and western grain growing regions in 2012. Growers were asked how beneficial they thought technology that could control where livestock grazed using electronic collars or eartags (virtual fencing) would be on their farm. Overall, of crop-livestock farmers 31% said very beneficial; 17% moderately beneficial and 19% slightly beneficial with producers with large farm sizes were more likely to expect the technology to be very beneficial (R Llewellyn 2015, pers.comm., 21 October 2015).
To effectively design and to efficiently deploy these innovative grazing technologies, the current grazing behaviour of livestock in large Mallee paddocks needs to be understood and quantified. This project has begun to address this knowledge gap by quantifying livestock (sheep) grazing in a large Mallee paddock with variable soil types.