ABSTRACT
Com {Zea mays L.) production in hilly areas often increases water runoff and soil erosion and may result in low crop yields. In a two-year study (1995-96) runoff, NO3-N, and P-PO 4 losses were measured in the second year from 0.0052 ha tiledrained com erosion plots which had received one of 5 soil tillage treatments: moldboard plow-disk (conventional tillage) (CT), no-till / direct-drill with band application of atrazine (Dual / Marksman) at 30% (NTB) and 100% surface application (NTS), no-till / direct-drill (chopped com residue) (NTR), and no-till / direct-drill following fall offset disking (NTO). In the year of establishment (first) com was grown on the conventional preparation, no-till (herbicide), and no-till with fall offset plots, and barley-red clover on the other two. Annual runoff and drainage water volumes were not affected by tillage systems. Runoff from NTB and NTS was lower (3.7 fold) than CT. The reduced tillage treatment of fall offset disking produced the second highest runoff and soil losses after CT. Annual NO3N and PO4 -P runoff losses were not significantly affected by tillage treatments, while NO3-N loss in drainage was lower in NTB as compared to CT (55 kg ha' 1 vs. 77 kg ha'1). Offset disking (NTO) contributed to the highest NO3-N losses with 94 kg ha'1. Intercropping barley-red clover with com provided maximum protection against erosion and minimum losses of NO3-N in drainage water.
