Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/22/2016
Publication Date: 9/29/2016
Citation: Anapalli, S.S., Pettigrew, W.T., Reddy, K.N., Ma, L., Fisher, D.K., Sui, R. 2016. Climate optimized planting windows for cotton in the lower Mississippi Delta region. Agronomy Journal. 6(4):1-15.
Interpretive Summary: High variability in rainfall and temperatures experienced in the Lower Mississippi Delta across years have rendered it difficult to develop planting windows and associate risks from short-term field experiments for advising producers. A solution to the problem is to derive planting date recommendations based on data collected with frequent plantings spread uniformly across crop growth seasons over the long-term (30 years or more) to account for variations in precipitation and other climatic variables at a location. Such long-term experiments are time-consuming and, so, not suited for deriving timely solutions keeping pace with changes in technology in cotton production. Scientists at the Crop Production Systems Research Unit, USDA ARS, Stoneville, Mississippi, combined short-term planting date experiments with a cutting-edge science-based agricultural system model and long-term climate data to develope long-term climate optimized planting windows for cotton. Planting windows from mid-March to the last week of May under rainfed conditions, and from the last week of April to the end of May under irrigated conditions, were better suited for optimum yields. Within these windows, rainfed cotton tended to lose yield from later plantings but irrigated cotton benefited. Irrigated cotton produced about 1000 pounds per acre seed cotton more than rainfed cotton, with irrigation water requirements averaging 5 inches per season. Under rainfed conditions, every planting had a 5% chance for seed cotton production to go below 1000 pounds per acre, 14% chance for below 1500 pounds per acre, and 27% chance for below 2000 pounds per acre. Information developed in this research can help Mississippi farmers in decision support for cotton planting.
Technical Abstract: Unique, variable summer climate of the lower Mississippi Delta region poses a critical challenge to cotton producers in deciding when to plant for optimized production. Traditional 2- to 4-year agronomic field trials conducted in this area fail to capture the effects of long-term climate variabilities in the location for developing reliable planting windows for producers. Our objective was to integrate a four-year planting-date field experiment conducted at Stoneville, MS during 2005-2008 with long-term climate data in an agricultural system model and develop optimum planting windows for cotton under both irrigated and rainfed conditions. Weather data collected at this location from 1960-2015 and the CSM-CROPGRO-Cotton v4.6 model within the Root Zone Water Quality Model (RZWQM2) were used. The cotton model was able to simulate both the variable planting date and variable water regimes reasonably well: relative errors of seed cotton yield, above-ground biomass, and LAI were 14, 12, and 21% under rainfed conditions and 8, 16, and 15% under irrigated conditions, respectively. Planting windows under both rainfed and irrigated conditions extended from mid-March to mid-June; windows from mid-March to the last week of May under rainfed conditions, and from the last week of April to the end of May under irrigated conditions were better suited for optimum yield returns. Within these windows, rainfed cotton tends to lose yield from later plantings but irrigated cotton benefits. Irrigated cotton produced about 1000 kg ha-1 seed cotton more than rainfed cotton, with irrigation water requirements averaging 15 cm per season. Under rainfed conditions, there is a 5, 14, and 27% chance that the seed cotton production is below 1000, 1500, and 2000 kg ha-1, respectively. Information developed in this paper can help Mississippi farmers in decision support for cotton planting.