TILLAGE EFFECTS ON CORN PRODUCTION AND SOIL PHYSICAL CONDITIONS

Row crop production on highly erodible soils of the Piedmont in the so utheastern USA is often limited by surface sealing, excessive surface water runoff, soil erosion, and low crop yields. The effects of four t illage practices on corn (Zea mays L.) growth and soil properties on t wo crust-prone soils were evaluated. Tillage treatments at two Piedmon t locations, Oxford and Reidsville, NC, were no-till (NT), in-row subs oiling (IRS) (1987 only), chisel plow (CP), and moldboard plow-disk (M P). Residue cover was 1% for MP and ranged from 75 to 87% for NT and 3 8 to 27% for CP. The interaction between tillage, soil properties, and plant performance was complex. Mean bulk density of the Ap horizon at Reidsville for the 2-yr period was 1.56 Mg m(-3) for NT, compared wit h 1.48 Mg m(-3) for CP and 1.46 Mg m(-3) for MP. Cone index was not af fected by tillage but was greatest in the trafficked interrow, 3.50 MP a, compared with 1.91 and 1.09 MPa in the row and nontrafficked interr ow, respectively. Mean corn grain yield for the four year-locations wa s least, 1.23 Mg ha(-1), for MP, compared with 2.97 Mg ha(-1) for NT a nd 2.44 Mg ha(-1) for CP; mean yield for IRS in 1987 was 3.69 Mg ha(-1 ). Tillage practices leaving crop residues on the soil surface, such a s NT, CP, and IRS, can reduce or eliminate surface crusting, increase infiltration, and reduce surface runoff and soil loss while increasing crop yield.