Irrigation Management and Efficiency for Cropping Systems in the Fort Cobb Reservoir Experimental Watershed

Goals / Objectives
Goal to develop applied research and/extension activities focused on a better quantitative understanding of the irrigation practices and irrigation efficiency in the Rush Springs aquifer area, particularly the Fort Cobb Reservoir Experimental watershed (FCREW). Specific objectives include: .1) quantify the irrigation water budget for representative production fields in the Fort Cobb Reservoir watershed, including well metering on selected wells; 2) determine the irrigation efficiency of systems in the FCREW; 3) improve the irrigation algorithms in SWAT and APEX watershed and crop models, and; 4) develop recommendations for producers to enhance water and nutrient use efficiencies of irrigated cropping in this area.

Project Methods
Several fields within the FCREW with soil, water, and crop conditions representative of the entire study area will be selected to conduct field scale irrigation monitoring and efficiency analysis. The participating producers will be engaged in the project from the very beginning by collecting information about their irrigation management methods and challenges. In addition, the types of sensors to be installed and their requirements in terms of maintenance and potential adjustments to cultural practices will be discussed with producers. Sensors will be installed at key locations at each field to continuously monitor irrigation applications. These sensors include, but are not limited to: rain gauges and flow meters to measure water inputs and soil moisture sensors at multiple depths to monitor soil water dynamics (crop water extraction, deep percolation, etc.). The information collected by sensors will be downloaded and analyzed on a frequent basis and then shared with participating producers to assist them with improving their irrigation management. In addition to continuous monitoring sites, the overall efficiency of the entire irrigation system from pumping station to the crop root zone will be evaluated at multiple times during each growing season using the instrumentation package that has been developed to test irrigation water and energy efficiency in Oklahoma Panhandle. The findings on irrigation management (mismanagement) and efficiencies (losses) will be disseminated through conventional and modern methods such as field days, local meetings, fact sheets, and SunUp videos. A major event for sharing the results with producers is the Oklahoma Irrigation Conference, which is held annually at Fort Cobb, OK and attracts many growers and crop consultants. The results will be further analyzed in conjunction with remotely sensed data (surface reflectance, canopy temperature, and ET estimates from the energy balance model) to expand field-scale information to the entire study area. Finally, the OSU team will collaborate with the ARS team to improve irrigation algorithms in the integrated SWAT-MODFLOW model to better account for the dynamic nature of irrigation decision making.