CORN RESIDUE COVER ON THE SOIL SURFACE AFTER PLANTING FOR VARIOUS TILLAGE AND PLANTING SYSTEMS

Crop residue left on the soil surface after planting is one of the mos t cost-effective soil erosion control practices, and is a primary comp onent of the majority of conservation plans that have been developed t o comply with the conservation provisions of the 1985 Food Security Ac t. However, from contacts in Extension meetings and demonstrations, it became apparent that farmers frequently misunderstood certain aspects of crop residue management, particularly the effects that tillage and other operations had on residue cover. To help address some of these questions, we measured percent residue cover remaining on the soil sur face after planting for 69 tillage and planting system treatments used in corn (Zea mays L.) residue. Eleven tillage systems, in conjunction with combinations of the use, and timing, of a stalk chopper and/or a knife-type fertilizer applicator, were evaluated. Only 24 of these st alk chopper/knife applicator/tillage system treatment combinations cou ld be classified as conservation tillage when a criterion of 30% or gr eater residue cover after planting was used. No-till was the only syst em that consistently provided residue cover levels that were statistic ally equal to or greater than 40%, the value used in a field study con ducted by the Soil and Water Conservation Society to assess conservati on plans.