Evaluation of the Quality of Diverted Water from the Red Bayou for Irrigation in Northwest Louisiana

Changyoon Jeong, Red River Research Station, AgCenter, Louisiana State University, Bossier City, LA 71112, cjeong@agcenter.lsu.edu; and Ernest Girouard, Louisiana Master Farmer Program, AgCenter, Louisiana State University, Rayne, LA 70578, EGirouard@agcenter.lsu.edu

Water availability is one of the major limitations to crop production and sustainability in many regions. In most cases, water availability is a climate-bound regional problem and is present all over the world including the northwest of Louisiana. For this reason, over the past few decades, there has been a growing interest in the development of alternative sources of water, including used diverted water. The diverted water systems conserve irrigation water supplies by enabling the capture and reuse for agricultural production. The Red Bayou project was initiated by the American Recovery and Reinvestment Act (ARRA) of 2009 and the project was partially supported by the Obama Administration to improve the nation’s infrastructure and enhancing a local economy. Thus, the NRCS and local communities collaborated to divert water from the Red River to the Red Bayou to facilitate the use of an alternative source of irrigation water, reduce water withdrawal rates from the aquifers, update aging flood control structures, reduce soil erosion, and improve the ecosystem. Since the completion of the diversion project in June 2014, the principle investigator at the Red River Research Station, LSU AgCenter has been monitoring water quality parameters for a preliminary data base. Although reliable supplemental irrigation water could extend irrigated agricultural acreages, in-depth research is required to understand the seasonal water quality changes and salinity impact on irrigated agricultural lands during irrigation. Our specific objectives are to monitor water quality parameters of seasonal variation and bioavailable forms from the diverted water, and evaluate the quality of diverted water on soil health and crop yields. Irrigation water quality from the Red Bayou was monitored weekly as a regular base sample and occasionally after a rain event. The measured salinity of irrigation water from the Red Bayou ranged between 596 and 1,057µS/cm, showed a seasonal variation, and was subjected to weather influence and local agricultural activities. Soil samples were collected at cotton fields of two different soil types (sandy and clay type) at the beginning of the crop season, and nutrient concentrations were measured. The average values of C and N were 1.25 % and 0.11 % in clay soil type and 0.49 % and 0.064% in sandy soil type, respectively. Carbon and nitrogen accumulated more at the beginning points in both cotton fields of sandy and clay soil types. Electrical conductivity (salinity) ranged from 52.35 – 58.83 µs/cm in sandy soil and 65.2 -105.56 µs/cm in clay soil. Electrical conductivity (EC) in sandy soil was slightly higher at the end of down-slope compared to the beginning of the irrigation point in the field. However, the measured EC in clay soil was 1.6 time higher at the beginning of irrigation point than the spot at the end of down-slope. Cotton yield was higher from clay soil compare to yield from sandy soil under irrigation with recycled tailwater. Research data showed that soil organic matter application is recommended in sandy soil to improve cotton yields.