Sulfur Fertilization and Sulfur Sufficiency Range for Contemporary Cotton Cultivars with High Yielding Potentials

Information is lacking on sulfur (S) nutrition characteristics of contemporary cotton (Gossypium hirsutum L.) cultivars and their responses to S fertilization in the United States. The objective of this study was to develop S fertilizer recommendations and S sufficiency ranges for contemporary cotton cultivars with high yielding potentials. Sixteen field trials were conducted on cotton across west Tennessee during 2014–2016. Five S application rates of 0, 11.2, 22.4, 33.6, 44.8 kg ha−1 were examined in a randomized complete block design with four replicates at each location-year. Lint yield was significantly increased by 8.5–9.8% with S applications of 11.2, 22.4, 33.6, 44.8 kg ha−1 in the soils with low S. Soil residual S level after harvest was significantly enhanced only at the highest rate of 44.8 kg S ha−1. However, lint yield or soil residual S did not respond to S application in the medium S soils. Leaf S concentrations of 3.9–8.2 g kg−1 at late bloom were needed for 95–100% of the highest yield in the low S soils, which were different from the current S sufficiency range of 3.0–9.0 g kg−1 being used in diagnosing cotton S nutrition. In conclusion, application of 11.2 kg S ha−1 is beneficial and adequate for cotton grown on low S soils. The S sufficiency range at late bloom was narrower for contemporary cotton cultivars than conventional cotton varieties. Sulfur management needs to be more accurate for contemporary cotton cultivars due to their narrower S sufficiency range.