Salinity Management in Pima Cotton Fields Using Sulfur Burner

Abstract

Core Ideas: Salinity and sodicity in irrigated cotton fields are reducing soil productivity, lint yield, and fiber quality in arid and semiarid regions of the world. Sulfur burner treatment of irrigation water can be used to tap native CaCO3 to produce CaSO4 in a safe manner. Calcium sulfate increases Ca availability in the root zone to counter Na, improve soil permeability, and leach salts to deeper depths. Salinity and sodicity are the dual problems affecting soil productivity, lint yield, and fiber quality in the irrigated pima cotton (Gossypium hirsutum L.) fields in far west Texas. This field study evaluated the effects of S burner-treated blended irrigation water on sodicity and salinity of the root zone, cotton lint yield, and fiber quality. Results indicated that pre-study soil salinity and sodicity exceeded the threshold levels in many areas within the 9.2-ha study site. One year of irrigation with S burner-treated water resulted in 19% reduction in salinity of the upper 0- to 30-cm depth and redistribution of salts at deeper depths. Average sodium adsorption ratio (SAR) of study site soils decreased by 3 to 5% at 0- to 15-, 30- to 45-, and 45- to 60-cm depths and reduction in the SAR range for 15- to 30- and 60- to 75-cm depths indicated redistribution of Na. Irrigation with S burner-treated blended water increased annual cotton lint yield by 20% compared with long-term average and improved fiber quality. However, 1 yr of irrigation with S burner-treated water did not reduce the maximum soil ECe and SAR values below the threshold levels at different depths. Multi-year studies are needed to confirm our results and quantify the duration required to restore soil quality, cotton yield, and fiber quality.