Developing a Site-Specific Soil Water Deficit Index Based on Alabama Mesonet.

Alabama is known to have plenty of water, however recent droughts have significant economic impacts on Alabama. Over the last 80 years Alabama has lost nearly 90% of its row crop agriculture due the lack of water for crops at critical stages of growth and development in the summers. Recently we have seen more and more irrigation systems installed in the agriculture fields of Alabama, but the water management plan in Alabama is not well-developed compared with neighboring states such as Georgia and Mississippi. In this paper, site-specific soil water deficit indexes (SWDI) were determined at different soil depths of each stations based on soil moisture and property measurements of Alabama Mesonet. Six stations (East View, WTARS, Allen, Cullman, Livingston, and Tuskegee) were selected to represent different soil types and different climate divisions. SWDI was compared and evaluated with atmospheric water deficit index (AWDI), crop moisture index (CMI) and modified palmer deficit index (MPDI). Results showed that SWDI generally agreed well with AWD, CMI and MPDI for uniform soil layer, but SWDI varied with depths and soil types at non-uniform soil layers at same climate division. The SWDI determined based on the ALMnet has the potential to support irrigation development and water management in Alabama, and can also be used to help accurately quantify drought severity.