The potential contribution of forage shrubs to economic returns and environmental management in Australian dryland agricultural systems

In face of climate change and other environmental challenges, inclusion of perennial forage shrubs in Australian agricultural systems has the potential to deliver multiple benefits: increased whole-farm profitability and improved natural resource management. The profitability of shrubs was investigated using MIDAS (Model of an Integrated Dryland Agricultural System), a bio-economic model of a mixed crop/livestock farming system. We found that including forage shrubs could increase farm profitability by over 20% for an optimal 10% of farm area in shrubs. The impact of shrubs on whole-farm profit accrues primarily through the provision of a predictable supply of “out-of-season” feed, thereby reducing supplementary feed costs, and through the deferment of grazing of pastures, allowing a higher stocking rate and improved animal production. The benefits for natural resource management include improved water use through summer-active, deep-rooted plants, reduced risk of soil erosion through year-round ground cover and/or wind breaks, reduced soil acidification, increased habitat for biodiversity, and effective carbon storage. Forage shrubs also allow for the productive use of marginal soils. Finally, we discuss other benefits of shrubs such as the effect on lambing and on livestock gut health. The principles revealed by the MIDAS modelling have wide application beyond the region.