Comparison of Two Tillage Practices in a Semi-Arid Cotton-Grain Sorghum Rotation

Conventional tillage (CT) cropping systems in semiarid regions of south Texas are associated with soil degradation and increasing fuel costs. The objective of the study was to evaluate the effects of no-till (NT) compared with CT on a dryland cotton (Gossypium hirsutum L.)-grain sorghum [Sorghum bicolor (L.) Moench] rotation system with respect to crop yields, yield stability, soil moisture and structure, and economics. The experiment (four replicated plots of each crop and tillage treatment annually) was conducted on a Vertisol at Corpus Christi, TX, from 2011 to 2015. Cotton yield was similar among tillage treatments, except for the drought year of 2013 when 86% greater yield occurred with NT and above average precipitation year of 2015 (15% greater yield for NT). Sorghum yield was impacted by tillage in 2012 when NT produced 33% greater yield than CT, whereas, in 2015, CT produced 28% greater yield. Yields were stable across crops and tillage treatment. Soil moisture was not impacted by tillage treatment; however, tillage caused bulk density to increase at 15- to 30-cm depth compared with 0- to 15-cm depth. All soil chemical properties remained constant, except NT had greater total soil N than CT in 2015. Cash costs for CT were greater than NT for both crops, and net cash farm income was positive only for NT cotton. No-till is a viable alternative for dryland farmers in this region because of stable yields and increased income.