Effects of Sulfur Application Rates and Foliar Zinc Fertilization on Cotton Lint Yields and Qualities

Sulfur deficiencies have increasingly occurred in crops due to declined use of S‐bearing fertilizers and reduced atmospheric S deposition. A field trial was conducted on an S‐ and Zn‐deficient soil at Jackson, TN in 2007–2010, to evaluate cotton ( Gossypium hirsutum L.) yield and fiber quality responses to S and Zn applications. Sulfur treatments of 0, 11, 22, and 34 kg S ha −1 were broadcast before planting. Zinc treatments of 0 and 0.29 kg Zn ha −1 were foliar applied at matchhead square. Soil S levels were increased by applying 34 kg S ha −1 in 3 out of 4 yr. Leaf S concentrations were increased by S applications. Application of 22 or 34 kg S ha −1 increased lint yields by 8 to 9% and micronaire by 4 to 5% averaged over the three normal growing seasons (2008–2010). Foliar Zn treatments had no significant effect on leaf Zn levels or lint yields and quality. A container‐grown cotton trial was also conducted to study effects of S deficiency on yield components. Plants were fed nutrient solutions with high or low S concentrations. The low S treatment reduced leaf S concentration but tended to increase leaf concentrations of other nutrients. Seedcotton per plant was reduced by S deficiency in 3 of 4 yr, with fewer bolls per plant and fewer locules per boll. Results indicate that application of 22 to 34 kg S ha −1 may be beneficial for no‐till cotton on soils testing low for S in Tennessee and similar environments.