Profile Modification of a Fragiudalf to Increase Crop Production

Abstract
Root development and crop yields are greatly reduced in soils having fragipan layers because of restricted air and water movement, high bulk densities and soil strength, and high acidity. In the first year after soil profile modification by trenching of a Missouri Typic Fragiudalf, available water storage and yields of grain sorghum (Sorghum bicolor (L.) Moench) were increased. Within unmodified areas, sorghum yields averaged 1,841 kg/ha. Deep trenching without chemical or physical additives increased yields to 4,322 kg/ha. Mixing lime, fertilizer, and sawdust with the soil material within the trenches increased grain sorghum yields to 5,987 kg/ha. The sawdust significantly increased water storage and water extraction, resulting in the grain yield increase.Reexcavation of a pit used by the Soil Conservation Service for soil series identification of the Hobson soil showed no signs of soil density or strength reformation during the 16‐year period since the pit was refilled.