The Role of Forages in Sustainable Cropping Systems of Southern Australia

The historical context, recent trends, and possible future role of forages in cropping systems are reviewed. Three recent themes will be developed: 1) The successful exploitation of genetic diversity resulting in commercial development of new legume species as pasture cultivars with specific traits better suited to the needs of current farming systems. 2) Improved understanding of key soil processes under grazed pastures, particularly soil water and soil nitrogen, and how these processes impact on indicators of sustainability like deep drainage and nitrate leaching. 3) An emerging capacity for predicting the effect of pasture-crop sequences on soil processes, crop growth and grain yield. In response to changing economic pressures and threats to sustainability, new farming systems involving forages are continually evolving. Increasing cropping intensity has placed pressure on pasture-crop systems that rely on self-regeneration of annual legumes following crops. One response has been the emergence of phase cropping systems, where a sequence of pasture years is followed by a sequence of cropping years. Another response has been an expansion in the area of lucerne grown in rotation with crops. In the future, forages in cropping systems will continue to fulfil the traditional roles of diversifying farm income through livestock production and supporting the cropping enterprise through maintenance of soil fertility. But increasingly, forages will be utilised to maintain the sustainability of agricultural production systems. Examples include competitive forages as a component of integrated weed management and high water use forages for reducing recharge and the associated spread of dryland salinity