Properties and productivity of recently tilled grass sod and 70-year cultivated soil

ABSTRACT:

The 1985 Food Security Act established the Conservation Reserve Program (CRP) whereby highly erodible land was placed into sod or trees for 10 years. Detailed information on the effects of grass sod on soil properties and productivity is needed in order to fully understand the impact of returning the retired land to production. In this study, land that had been in grass sod for about 30 years was converted to cotton and sorghum production in 1985. Yields were measured from 1985 through 1991 on that land and land that was continuously cultivated for 70 years. Selected soil properties were also measured after the study. Silt content, organic matter, and wet soil stability were higher in the surface soil of the grass sod than in the cultivated fields. Clod density was lower in the grass sod than in the cultivated fields. Sorghum biomass was higher in the recently converted field but yield differences between the converted and continuously cultivated field were not observed after fertilization. Cotton lint yields did not increase on the recently converted grassland. These results suggest economists must consider the crop grown when estimating yields of crops grown on land previously in the CRP. Crops may differ in yield and how they respond to management after conversion.