Site Specific Management in Cotton:Seeding Rates in a Highly Variable FIELD in Northeast Arkansas.

American cotton producers must reduce production costs to improve profitability. Adjusting seeding rates represents one option to lower input costs, and previous research findings in SE states have suggested that rates can be reduced without affecting yield.  With improved reliability of rate controllers on precision planters, crop managers can vary seeding rates within a field based on soil, landscape, or other production considerations.  Development and validation of guidelines for prescription planting is needed. This presentation will summarize results from a 2-year on-farm study in northeastern Arkansas to evaluate seeding rate and soil type on plant development and yield in a field with highly variable soils.  Historical data from yield maps, soil electrical conductivity EC measurements and soil texture samples were used to sub-divide the field into three soil EC classifications: sand blow, sandy loam and clay.  Treatments included seeding rates of 1.5, 3.0 and 4.5 seeds per foot, as well as a variable rate treatment with rates applied based on soil EC. One 12-row planter swath across the field was one treatment strip, and there were 6 strips per treatment. Stand density evaluations were made using transect sampling across each soil textural zone. Seedling emergence patterns were evaluated. Season long plant monitoring included evaluations of nodal development, fruit retention, plant structure, and maturity. Yield and fiber quality assessments were made with hand-picked samples and use of yield monitor data. There were significant differences in yields among soil EC classes with higher yields from plants grown in sandy loam compared to plants growing in sand blow or clay soils. Yield monitor data indicated lower yields associated with the lower seeding rates. Results indicate seeding rates adjusted for soil type may reduce production costs, but successful stand establishment remains a critical hurdle.