| Popis: |
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. Tbe 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. Tbe 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. |
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