@article {Malapati287, author = {A. Malapati and K.F. Bronson and J.D. Booker and W.H. Hudnall and A.M. Schubert}, title = {Soil profile sulfate in irrigated southern high plains cotton fields and Ogallala groundwater}, volume = {66}, number = {5}, pages = {287--294}, year = {2011}, doi = {10.2489/jswc.66.5.287}, publisher = {Soil and Water Conservation Society}, abstract = {Sulfate (SO4) is one of the most important anions in soils and groundwater in semiarid regions, including west Texas. Crops{\textquoteright} sulfur (S) requirement is about 10\% to 20\% of the nitrogen requirements. However, there is far less information on soil test SO4-S (S in the SO4 form [sulfate-S]) for the western United States, compared to the humid eastern United States. The deposition of S from the atmosphere has declined nationwide, as coal-fired power plants have been scrubbing their emissions of S. This, combined with greater cotton yields and the lack of S fertilization on the Texas Southern High Plains (SHP) point to the need for a soil profile SO4-S assessment. The first objective of this study was to assess residual soil profile SO4-S content in irrigated cotton (Gossypium hirsutum) fields across a range of soil types and counties of the Texas SHP. The second objective was to compile regional SO4-S concentration data from the Texas Water Development Board irrigation well water quality database and analyze Ogallala groundwater SO4-S levels by county, soil map unit, and well depth. Soil profile (0 to 0.9 m [0 to 36 in]) SO4-S content ranged from 120 to 475 kg ha-1 (107 to 424 lb ac-1) among seven center-pivot fields sampled. About half of this S was in the 0.6 to 0.9 m (24 to 36 in) soil layer, which typically was sandy clay loam or clay loam in texture. Well water SO4-S concentration ranged from 9 to 220 mg L-1 (ppm) in clayey soils with deep groundwater to sandy soils with shallow groundwater, respectively. Groundwater SO4-S concentration was greater than the USEPA drinking water standard of 83 mg L-1 in 32\% of the wells, especially in the southeastern corner of the study area. There was no consistent relationship between soil map unit and SO4-S content in the soil profile (0 to 0.9 m). A significant negative relationship between well depth and well water SO4-S concentration was observed in all the eleven-county study area of the SHP of West Texas. In conclusion, soil profile SO4 content to 0.9 m is high in SHP irrigated cotton fields and in most cases should be adequate for crop S nutritional requirements.}, issn = {0022-4561}, URL = {https://www.jswconline.org/content/66/5/287}, eprint = {https://www.jswconline.org/content/66/5/287.full.pdf}, journal = {Journal of Soil and Water Conservation} }