Irrigation water fluxes in the Fort Cobb reservoir experimental watershed

Authors: DATTA, SUMON - Oklahoma State University; TAGHVAEIAN, SALEH - Oklahoma State University; MEHATA, MUKESH - Oklahoma State University; Moriasi, Daniel

Submitted to: Grazinglands Research Laboratory Miscellaneous Publication
Publication Type: Abstract Only
Publication Acceptance Date: 11/15/2018
Publication Date: N/A
Citation: N/A

Interpretive Summary: Abstract only

Technical Abstract: Agricultural production in the Fort Cobb Reservoir Experimental Watershed (FCREW) has been primarily driven by center-pivot irrigation systems withdrawing water from the Rush Spring aquifer. Because of predominant coarse- and medium-textured, highly erodible soils in the area, irrigation return flows may convey applied chemicals (nutrients, pesticides, etc.) to downstream land and water resources if irrigation practices and management are suboptimal. In addition, sediment loading may impair water quality in surface water reservoirs. Therefore, a study was undertaken using sensor technologies and modeling approaches to quantify irrigation water fluxes at field scale and to assess if irrigation applications are efficient. Soil moisture fluctuations were observed by installing soil moisture probes at different commercial fields within FCREW. Irrigation and precipitation rates were measured using tipping bucket rain gauges. Soil core samples were taken to determine soil moisture thresholds necessary for irrigation management. Finally, crop water use was estimated using the crop coefficient approach and data from the nearby Mesonet stations. The collected information was used to determine water fluxes and answer key questions such as how much deep percolation was generated under field conditions and if there was over- or under-application of irrigation water compared to crop water requirement. The results will help producers and decision makers determine best management practices to conserve water resources in the FCREW.