WHEAT STRAW DECOMPOSITION AND CHANGES IN DECOMPOSABILITY DURING FIELD EXPOSURE

Describing crop residue decomposition is important for assessing management practices that protect soil against wind and water erosion. Predicting wheat (Triticum aestivum L. em Thell) residue decomposition in conservation tillage systems requires information on C mineralization and changes in residue decomposability. The principal component of wheat residue is the stem. Wheat straw decomposition at the soil surface was followed during field and laboratory incubation studies. Straw samples were collected on nine dates during 377 d of field exposure and analyzed for weight loss. Total C, soluble C, carbohydrate, N content, and C mineralization were measured periodically during the exposure period. Amount and quality of soluble C was found to be important only during initial stages of fresh straw decomposition and was in consequential for field exposed straw.