Optimum sorghum planting dates in western Sudan by simulated water budgets

Abstract

The Soil-Plant-Air-Water (SPAW) model previously developed and tested was used to simulate soil water budgets and crop water-stress for sorghum in the dryland region of western Sudan. Limited climatic data were combined with general observations of sorghum growth and soils to provide daily water budgets at one site for 11 years. Probability distribution of computed water budget components and water-stress index resulting from simulation of nine possible planting dates for each year were used to determine the optimum planting period for minimal crop water-stress. The water budget analysis showed a distinct optimum planting period of June 20 to July 10 with planting in early July as the most likely for best production. These results agreed well with general experience. The technique will be similarly useful for other locations, for research designs of soil water management, yield forecasting, and planning and management of agricultural resources.