CORN YIELD IS EQUAL IN CONVENTIONAL, REDUCED, AND NO-TILLAGE AFTER 20YEARS

Reduced tillage has increased dramatically over the past several years and is expected to continue to increase in the future. Continuous no- till may become a popular tillage system with growers to facilitate co mpliance with government programs to control soil erosion. The objecti ve of this research was to evaluate the long-term effects of four till age systems and five fertilizer regimes on corn (Zea mays L.) yield. A 20-yr continuous-corn tillage x fertility study was conducted from 19 70 to 1990 on an Ebbert silt loam (fine-silty, mixed, mesic Argiaquic Argialbolls), an imperfectly drained soil at the Belleville Research C enter, Belleville, IL. Starter fertilizer did not increase corn height within a tillage system. Height was greater in no-till compared with conventional till (moldboard plow), reduced till (chisel plow), or alt ernate till (2 yr no-till, 1 yr moldboard plow) with or without a star ter fertilizer. There was no difference in population among tillage sy stems due to fertilizer treatment. Corn population was lower in no-til l compared with conventional till regardless of fertilizer treatment. Starter fertilizer did not increase yield in any tillage system. Corn yield averaged 5 to 7% lower in no-till compared with conventional til l or reduced till where a starter fertilizer was applied. There was no difference in yield among tillage systems when NPK was broadcast. Cor n yield was equal in conventional till, alternate till, reduced till, and no-till with fertilizer applied broadcast on an imperfectly draine d soil. Continuous no-till with an imperfectly drained soil does not r educe corn yield.