Sustaining Agriculture through Adaptive Management to Preserve the Ogallala Aquifer under a Changing Climate

Goals / Objectives
Objective 1: Calibration and validation of DSSAT System using lysimetric data. Objective 2: Enable adoption of tools and strategies for improve water use through tecnology transfer.

Project Methods
The DSSAT system will be calibrated and validated for daily ET and yield using the long term (1991-2014) data from four lysimeter fields managed by USDA-ARS Conservation and Production Research Laboratory at Bushland, TX. Two lysimeter fields each were managed under irrigated and dryland management practices representing typical water management practices in the southern OAR. Since 2013, all four lysimeter fields are managed under drip irrigation conditions to develop crop coefficients for crops grown with drip irrigation systems. Lysimeter data include crop growth characteristics such as leaf area index, crop height, and biomass; actual measured ET; timing and rate of irrigation applications; soil moisture measurements in different soil horizons; and crop yield for major crops grown in the OAR (corn, sorghum, winter wheat, cotton, and soybean). Calibration and validation of the DSSAT models will be conducted separately for both irrigated and dryland conditions to assess its capability to simulate ET and crop yield under two major prevailing water management systems in the OAR. Period of record (1991-2014) will be equally divided under each water management treatment for calibration and validation purposes. Efforts will be made to represent dry, normal, and wet crop production years equally in both calibration and validation periods. Performance of the DSSAT model will be assessed using performance statistics such as RMSE, Nash-Sutcliffe coefficient, and regression statistics. The Southern Plains Climate Hub will leverage it's partnerships to support tecnology transfer of the new tools and strategies through USDA prgrams, Extension activities, and private sector activities.