Tillage and Irrigation Impact on Early and Late Maturing Cotton Cultivars

CORE IDEAS: There was little interaction between tillage and irrigation on agronomic parameters.Excessive rainfall minimized agronomic benefits of the rolled rye cover crop.Continuous experiments are likely optimal to properly evaluate cover crop systems. Concerns surrounding agricultural water use have increased interest in investigating more efficient cotton (Gossypium hirsutum L.) production practices. A study was conducted to determine potential water savings from using a conservation tillage system employing a cereal rye (Secale cereale L.) cover crop. The performance of early and late maturing cotton cultivars was assessed in two tillage systems, conventional or strip tillage with a rye cover crop, under various irrigation levels (100, 75, and 50% of University of Georgia recommendations, and non‐irrigated) to determine the effect of crop growth, development, and yield in Camilla, GA (2013 and 2014), Moultrie, GA (2014), and Vienna, GA (2014). At Camilla, increases in irrigation typically benefited the cotton crop regardless of tillage treatment; however, there was little difference between the two highest irrigation treatments, suggesting that application rates <100% recommendations could result in water savings. During 2013, excessive rainfall resulted in minimal soil moisturedifferences; subsequently, cotton growth, development, and yield were negatively impacted under strip tillage compared with conventional. Although almost half the rainfall was received in 2014 compared with 2013, and the conservation tillage system benefited crop growth and development, no yield differences were observed. At Moultrie and Vienna, either no difference between tillage systems or only benefits to crop growth and development in the conventional tillage system occurred. Results illustrate that the potential impact of cover crops is highly dependent on environmental conditions and is likely minimal under slight to moderate water deficit conditions, but can be detrimental when excessive rainfall occurs.