Sulfur Dioxide as a Source of Sulfur for Wheat

Abstract

AbstractSulfur dioxide was injected into the soil as a source of S for wheat in greenhouse and field studies with S‐deficient Athena and Palouse silt loam soils. Yields were approximately doubled when SO2 was applied at a rate of 2.5 ppm S in the greenhouse. Higher rates of SO2 up to 500 ppm S gave little additional growth. Plant growth responses to SO2 and gypsum at 10 ppm S were almost identical. In greenhouse experiments SO2 applied at 2,500 ppm S greatly reduced plant growth, and 5,000 ppm S proved lethal to the plants soon after emergence. Concentration of S in plants was directly related to rate of S application. In field trials, SO2 was applied at rates of 8, 16, 32, and 64 lb S/acre. No adverse effects were noted at the higher rates of application. Sulfur dioxide compared favorably with gypsum as a source of S with respect to plant growth response, total sulfur uptake and wheat yield in the greenhouse, and with respect to total S uptake in the field.