Location: Soil and Water Management ResearchTitle: Analysis of returns above variable costs for management of Verticillium wilt in cotton Author
Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2015
Publication Date: 1/30/2016
Citation: Bordovsky, J.P., Keeling, J.W., Wheeler, T.A., Smith, J.G., Woodward, J.E. 2016. Analysis of returns above variable costs for management of Verticillium wilt in cotton. Journal of Cotton Science. 20(1):56-66. Interpretive Summary: Cotton is a major crop on the Texas High Plains; however, future production is threatened by biotic and abiotic stresses. Scientists from Texas A&M AgriLife Research in ARS led Ogallala Aquifer Program conducted a large plot study at Halfway, TX, to assess management options to reduce the effects of the biotic stress caused by the disease of Verticillium wilt and boost returns on variable costs (RVC). A crop rotation of two years of cotton followed by a year with sorghum resulted in higher RVC than continuous cotton, and irrigation rates of less than 80 % replacement of evapotranspiration had higher RVC. These results indicate that conditions that minimize Verticillium wilt resulted in a higher potential for profits for cotton on the Texas High Plains.
Technical Abstract: A large plot study located in Halfway, TX, was conducted from 2007 to 2013 in an irrigated field infested with Verticillium wilt. Management options (crop rotation, irrigation amount, variety election) and combinations of options that can reduce this disease were compared using returns above variable costs (RVC) analysis. A continuous cotton system was compared with a crop rotation system (2 yr. cotton and 1 yr. sorghum). Irrigation rates consisted of a base (1.0B), base + 50% (1.5B), and base 50% (0.5B) rates. From 2007 to 2009, 1.0B targeted 80% of the evapotranspiration (ET) needs of cotton, and from 2010 to 2013, 1.0B targeted 60% ET. Varieties planted were tolerant or susceptible to Verticillium wilt. Data collected included wilt incidence, cotton lint yield, loan value for lint, sorghum yield, fertilizer types and amounts, and total irrigation applied. Cotton prices were approximately $1.15 and $1.54/kg lint ($0.52 to 0.70/lb) (adjusted up or down by actual loan value of cotton fiber), and sorghum was valued at $0.185/ kg ($8.40/cwt). Crop rotation generally resulted in higher RVC than continuous cotton, although higher cotton prices, and ET = 60% (drier conditions) could result in both systems having similar RVC. The 1.5B rate had higher RVC, but as irrigation increased above 80% of cotton needs, RVC was reduced compared with 1.0B. The 0.5B rate resulted in lower RVC than the 1.0B rate, except when ET = 80% and a susceptible variety was grown. The 1.5B rate combined with a tolerant variety always had higher RVC than growing a susceptible variety. The combinations of 1.5B rate and growing continuous cotton resulted in the most Verticillium wilt. Conditions that aggravated Verticillium wilt resulted in lower RVC.