RESIDUAL SOIL WATER IN WESTERN KANSAS AFTER CORN HARVEST

Water shortage is the primary factor limiting crop production in the USA’s westcentral Great Plains, and agricultural sustainability depends on efficient use of water resources. Precipitation is limited and sporadic with mean annual precipitation ranging from 16 to 20 inches across the region, which is only 6080% of the seasonal water use for corn. Yields of dryland crops are limited and variable and some producers have used irrigation to mitigate these effects. Continued declines within the Ogallala Aquifer will result in a further shift from fully irrigated to deficit or limited irrigation or even dryland production in some areas. As this occurs, producers will desire to maintain crop production levels as great as possible while balancing crop production risks imposed by constraints on water available for production. Efficient utilization of plant available soil water (PASW) reserves is important for both dryland and irrigated summer crop production systems.