Effect of Sulfur Content of Straws on Rates of Decomposition and Plant Growth

Sulfur deficiency must be considered in management of crop residues. With adequate N, P, and K, the decomposition rate of straw in soil low in sulfates depended on the S content of the straw. Incubation studies showed that unless S fertilizer is added, the S content of straw must exceed about 0.15% for a maximum rate of straw decomposition. Growth of winter wheat ( Triticum aestivum L. ‘Wichita’), in the greenhouse, on a NPK‐fertilized soil was governed by the S content of straw mixed in the soil. Straws with < 0.15% S added to soil depressed wheat growth, but straws with a higher S content increased yields compared to the no‐straw treatment. When S was added along with N, P, and K, the S content of the straws had no effect on wheat growth.