Crop Water Use Efficiency throughout the Brazos River Basin, Texas.

Estimation of crop specific water requirements are essential to maximize water use efficiency. Water requirements for selected crops (Cotton, corn, sorghum and wheat) at different locations across the Brazos River basin, Texas (Lubbock, Williamson, Brazos and Fort Bend County) were calculated using the Irrigation Management System (IManSys) model (Fares, 2012). IManSys calculates runoff, drainage, canopy interception, and effective rainfall based on plant growth parameters, soil properties, irrigation system, and long-term daily weather data (rain and evapotranspiration). Planting date, harvesting date and growing season of each crop were selected based on the geographic location of the area. The water requirement for sorghum is comparatively lower than cotton, corn and wheat. Water requirement for cotton is higher than other three crops at Williamson, Brazos and Fort Bend Counties whereas water requirement for wheat is higher than other three crops at Lubbock. Runoff, drainage and interception are different according to crop types and location. Further study on water use and returns from different crops will help to identify best crop for a specific location.