Influence of Sulfur Fertility on Wheat Yield Performance on Alluvial and Upland Soils

Abstract

Abstract: In recent years, sulfur (S) deficiencies in winter wheat (Triticum aestivum L.) have become more common, particularly on coarse‐textured soils. In Study I, field experiments were conducted in 2001/2002 through 2003/2004 on Mississippi River alluvial soils (Experiment I) and an upland, loessial silt loam (Experiment II) to evaluate the influence of spring S rates of 0, 5.6, 11.2, and 22.4 kg ha−1 and a fall rate of 22.4 kg sulfate (SO4)‐S ha−1 on grain yield of three varieties. In Study II, field experiments were conducted in 2001/2002 and 2004/2005 on alluvial soils to evaluate the influence of spring S rates of 0, 5.6, 11.2, and 22.4 kg SO4‐S ha−1 in fields where S‐deficiency symptoms were present. Grain yield response to applied S occurred only on alluvial, coarse‐textured, very fine sandy loam soils (Study II) that had soil SO4‐S levels less than the critical level of 8 mg kg−1 and organic‐matter contents less than 1 g kg−1 in the 0‐ to 15‐, 15‐ to 30‐, and 30‐ to 45‐cm depths. Soil pH increased with soil depth. Optimum S rate was 11.2 kg SO4‐S ha−1 in 2001/2002 and 5.6 kg SO4‐S ha−1 in 2004/2005. On the upland, loessial silt loam soil, soil SO4‐S levels accumulated with depth, whereas organic‐matter content and pH decreased. In the loessial soils, average soil SO4‐S levels in the 15‐ to 30‐ and 30‐ to 45‐cm soil depths were 370% greater than SO4‐S in the surface horizon (0 to 15 cm).