ABSTRACT
Probabilistic forecasts of various aspects of drought are possible using fairly simple water balance and budgeting approaches. In order to forecast drought, very careful definition of terms is needed. Drought, therefore, needs to be defined in a number of ways, depending on the interests of the user of the definition. A water balance model has been developed for dryland fanning situations. The model requires input of rainfall, potential evaporation, and soil water-holding and transmission characteristics. A water balance model has been developed to trace the movement of water in a soil. The model boundaries may be from plot size up to river basin size. Since the severity of past droughts can be assessed, there is also the possibility of assessing the likelihood of experiencing droughts with particular severity or duration characteristics in the future. When drought conditions occur at planting, or the probability of agricultural drought developing is high, this procedure can assist farmers who must make critical management decisions.
