Effects of irrigation and sulphur application on soybeans grown on a Norfolk Loamy sand

Abstract Plant sulphur deficiencies may develop in the Coastal Plain of Southeastern United States because of the humid climate and low soil sulfate levels. This study was conducted to evaluate the interactive effect of irrigation and sulphur fertilization on dry matter accumulation, yield, and sulphur content of Bragg (Glycine Max (L.) Merr) soybeans grown on a Norfolk loamy sand (Typic Paleudult). Rainfall distribution was sufficient to prevent plant moisture stress until the late flowering stage, but a subsequent drought during the pod fill stage resulted in an 86% yield increase due to irrigation. Dry matter accumulation was also increased by 26% during the seed development stage with irrigation. Sulphur fertilization had no significant effect on soybean yield or dry matter accumulation. However, sulphur concentration in soybean leaves and stems were significantly higher in the sulphur‐amended plots during the vegetative growth stage. Neither irrigation nor applied sulphur affected soybean protein or ...