Soil carbon content was determined for several management practices in central Texas. The effect of management was determined by measuring organic carbon content of soil samples archived in 1949 and samples obtained in 2004 from the same fields and soil depths. Management practices included: small grain and row crop production, row crop production prior to grass forage and hay production. The effects of row cropping were mixed, possibly because of the increase in seeding rate and fertilization over time. Soils previously cropped and then turned to grass production generally had an increase in soil organic carbon.