A tillage project was initiated in 1989 at the University of Illinois Dixon Springs Agricultural Research Center in southern Illinois to evaluate conservation tillage systems for land being removed from Conservation Reserve Program (CRP). No‐till (NT), chisel plow (CP), and moldboard plow (MP) tillage systems on a Grantsburg silt loam (fine‐silty, mixed, mesic Typic Fragiudalf) soil were studied. The soil has a fragipan at approximately 26 in. below the surface on a 6.5% east facing slope. The tillage treatments were replicated eight times on 30 by 40 ft plots. The area had been in tall fescue [Festuca arundinacea (L.) Schreb.] sod. For the project, corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] were grown on a 6‐yr rotation. Economic data were estimated for the three tillage systems using a simulation model to select equipment and estimate costs. The objective was to determine crop yields and to compare returns of the tillage treatments applied to CRP sod. Based on 6 yr of crop yield measurements (3 yr corn and 3 yr soybean), NT and CP systems appear to result in improved long‐term productivity of sloping soil compared with MP. Machinery requirements and costs were lower with NT than with the two other tillage systems. MP had the greatest machinery requirements and highest costs and highest corn yield only in 1989. Crop yields with the NT system improved compared with the yields with MP and CP systems each year with NT resulting in the highest crop yield in the fourth, fifth, and sixth years with the differences statistically significant the last two crop years. The NT system provided the highest net income and the MP system the lowest over the 6 yr study. Net income with NT system was $32/acre per yr higher than with the CP system (simple average without time valuation adjustment) and $40/acre per yr higher than with the MP system. The NT system reduced soil loss from erosion to below the current and future soil loss standards. Research Question The Food Security Act of 1985 and the 1990 Farm bill have resulted in millions of acres of erodible land previously in row crops being put into the Conservation Reserve Program (CRP). It is not known how long this program will be continued or what will happen to the land when it is released. Any conversion of CRP land back to corn and soybean production could require conservation tillage systems such as no‐till and chisel plow to meet soil erosion standards. Most farmers accept the fact that conservation tillage systems significantly reduce soil erosion and desire to adopt such systems. The primary concerns of farmers considering the switch to conservation tillage are the effects on crop production and profitability. The objectives of this study were to determine crop yields and to compare net income of the conservation tillage treatments with the moldboard plow system when applied to sloping and eroded CRP land in sod. Literature Summary Goals of sustainable agriculture include reduced soil erosion, maintenance and restoration of crop productivity, reduced pol...

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