Effects of Sulfur Application Rates On Lint Yield and Fiber Quality of No-till Cotton.

Little information is available about S and Zn nutrition on cotton yield and quality in the mid-South. The objective of this study was to investigate the effects of S and Zn applications on cotton yield and fiber properties. A field trial was conducted in a Dexter loam with low testing S and Zn at Jackson, TN from 2007 through 2010. Sulfur treatments of 0, 10, 20, and 30 lb S/ac were broadcast before planting. Zinc treatments consisted of 0 and 0.26 lb Zn/ac foliar applied at matchhead square. A container grown cotton trial were conducted from 2007 to 2010, in which plants were fed nutrient solutions with low S (0 to 1 ppm) or high S (2 to 20 ppm) treatments, respectively, plus 11 other essential elements. Sulfur treatments were applied from about 30 to 75 days after planting except 2007. Mid-season soil testing reflected the 30-lb S rate. Leaf S concentrations were increased by S applications. Application of 20 or 30 lb S/a increased lint yield by 8 to 10% on average. However, foliar Zn spray had no effect on soil testing Zn, leaf Zn, or yield. Neither S nor Zn application had effects on fiber quality. In container grown cotton trial, low S treatment reduced seed cotton weight per plant, bolls per plant, weight per boll, and locules per boll; low S treated plants produced a greater proportion of bolls at first position fruiting sites. Sulfur application is beneficial for no-till cotton on low-testing S soils in Tennessee.