2019 ASHS Annual Conference

The declining water table of the Ogallala Aquifer raises a question on the environmental and economic sustainability of growing conventional field crops on the Texas High Plains. Growers in the region have been looking for alternatives to conventional cropping systems to increase revenue per unit of irrigation water applied. Growing high-value vegetables has been suggested as an option, but reliable scientific information is lacking. To address this shortcoming, a field study was conducted to assess the efficacy of different irrigation practices for growing vegetables in the region. Sweet corn, peppers, and tomatoes were grown under three irrigation practices -- surface drip irrigation without plastic mulch (Ctrl), surface drip with plastic mulch (Mch), and center pivot sprinkler irrigation (Pvt). Meteorological variables and soil water were measured to calculate crop evapotranspiration (ET) and crop water use efficiency (WUE, defined as the ratio of yield and ET). Physiological parameters at the leaf level were also measured during the growing season. No differences were found at the leaf level physiological parameters, including photosynthesis rate, transpiration rate, and intrinsic or extrinsic WUE among irrigation practices for all three crops. Larger yields resulted under drip irrigation (Ctrl and Mch) compared with sprinkler irrigation (Pvt) for all of the three crops, although the yields under Ctrl and Mch did not differ. Crop ET under Ctrl and Mch was less than that under Pvt, resulting in increased WUE, under drip irrigation compared with sprinkler irrigation. Surface drip irrigation has greater capital expense and maintenance requirements compared with center pivot sprinkler, but may be justified by larger yields and WUE.