Dryland farming systems rely on the soil to store and release water and nutrients to meet crop demand. Soil water storage is dynamic and changes as a result of a balance between water inputs (rainfall, irrigation) and outputs including evaporation, plant transpiration, runoff, and deep drainage beyond the root zone.
Soil water managements ultimate aim is to improve the efficiency with which rainfall is converted into crop and pasture yield. This involves increasing the size of the bucket (amelioration) and optimising the production system for a given level of water storage (mitigation). Given that soil texture cannot be readily changed, soil water storage amelioration focuses on removing obstructions to water flow into the bucket and increasing the bucket size through rooting depth. In terms of mitigation, knowing how much plant available water is stored allows farmers to predict yields and manage inputs (fertiliser, pesticides) to maximise their profits.