Cotton Response in Non-Traditional Crop Rotations at Low Irrigation Levels

摘要

Significant changes such as declining water tables and the need for crops other than cotton are occurring on the Texas South Plains and affecting production decisions. A field evaluation was conducted to compare yield and total water use from a continuous cotton cropping system to cotton in three-year rotations that replaced every third crop with BMR forage sorghum, non-BMR forage sorghum, safflower, and sunflower and where seasonal irrigation volumes were limited to 0, 76 and 152 mm per year. Following the dry growing season in 2012, soil water content, cotton yield and WUE in 2013 tended to be higher in treatments having continuous cotton compared to cotton in any of the rotations where alternative crops had been grown the previous year. In 2014,the alternative crop rotations resulted in similar cotton yield and WUE as continuous cotton with the exception of those having sunflower and non-BMR sorghum in the previous year at the 152 mm seasonal irrigation level. In these cases, yield and WUE weresignificantly greater than continuous cotton. In both years, increases in WUE occurred with each incremental increase in seasonal irrigation indicating that the concentration of available irrigation may be the better water use option than spreading water over larger areas. To date there are no consistent results indicating cotton in rotation with any of the four alternate crops was better or worse than continuous cotton in terms of water use.