Soil Water Effects on No-till Corn Production in Strip and Completely Killed Mulches

No-till row cropping in plant residue mulches can effectively eliminate the high erosion rates of clean tilled, rolling soils in the Southern Piedmont. This study was conducted to evaluate corn (Zea mays L.) production on two mulches with five soil water treatments and a uniform high fertility level. The statistical design was a randomized block with mulches as main plots and irrigation levels on the split plots. Each treatment was replicated three times. The mulch treatments were viable fescue sod with corn planted in the same 20-an strips of sod killed annually prior to planting (SK); and a completely killed mulch (CK) of fescue, or winter rye on the same plot area and in the sequence of fescue-corn (1973) followed by winter ryecorn (1974 and 1975). Soil water treatments were: rainfall only (M₁), rainfall plus sprinkler irrigation when soil water potential in the 0-30 cm soil depth averaged -10 (M₅), -5 (M₃), or -2 (M₄) bars, and 5 cm/wk (M₅). Corn received annually about 450 kg/ha N; P, K, and Mg additions were based on soil analysis. Both rescue and winter rye received 45 kg/ha each N, P, and K in the fall. Corn grain and stalk yields on the CK mulch were significantly higher than those on the SK mulch. Maximum grain yields occurred for both mulches on the M₄ water treatment; stalk yields were largest on M₃ M₃, and M₄, and depressed on M₅. Winter and summer fescue forage yields were influenced by corn water treatments, but rye forage yields were not. Fescue stand count seemed to reach an equilibrium after the first full year, ranging from 30% after corn harvest to 60 percent before corn planting. Corn ear leaf nutrients which were within the sufficiency range for all treatments were N, P, Ca, Mg, Fe, Cu, Mn, and Zn. Potassium was marginal for SK treatments M₁, M₂, M₃, and M₄; however, although no visual plant deficiency symptoms were observed. Boron tissue concentrations were marginal for SK treatments M₁, M₂ and M₃ Corn can be grown successfully either in annually stripkilled fescue, or in completely killed mulch. Corn grain and stalk yields and total biomass production were consistently higher at all soil water levels for the CK mulch.