Row‐Plant Spacing and Broiler Litter Effects on Intercropping Corn in Tall Fescue1

Abstract

AbstractConservation tillage methods are needed to produce grain and forage for an important livestock industry on the highly erosive soils of the southeastern U. S. The objective of this research was to evaluate the effect of row widths, corn spacing within the row, and fertility level on the yield of corn (Zea mays L.) and Kentucky‐31 tall fescue (Festuca arundinacea, Schreb) when the corn was no‐till planted into 20‐cm killed strips of tall fescue grown under irrigated conditions in Cecil sandy loam (Typic Hapludult, clayey, kaolinitic, thermic). Corn row widths of 51 and 102 cm were the main plots, within‐row plant spacings of 16, 29, 38, and 47 cm were subplots and fertility levels of 9 and 18 metric ton/ha broiler litter and conventional fertilizer (358,134, and 268 kg/ha N‐P‐K, respectively) were sub‐sub lots in a randomized block design. The study was conducted for two corn seasons and two tall fescue seasons on the same plot area.Optimum corn plant density for obtaining the highest possible possible corn yields, while simultaneously maintaining the tall fescue sod, averaged 60,0000 plants/ha for the three fertility treatments. Average corn grain yields at this optimum plant density were 6.3 metric tons/ha for the 9 metric tons/ha broiler litter, 10.8 metric tons/ha for the 18 metric tons/ha broiler litter, and 8.7 metric tons/ha for the conventional fertilizer treatments. Based on total‐N analysis of broiler litter, the N from broiler litter was about 77% as efficient as N supplied from NH4NO3, in producing corn yield. Comparing similar plant densities with different row and plant spacings, we found that fescue yields were 2.6 times greater during the winter period under a 102‐cm wide row with plants spaced 16 cm apart in the row than under a 51‐cm wide row with plants spaced 29 cm apart within the row. Corn yields or corn plant populations were not significantly different at these two planting configurations. Despite the reduced sod area due to the herbicide killed strip, annual yields of tall fescue were also reduced at narrow row spacings because of decreased stand and sod vigor. This study illustrates the corn plant population and planting geometries which can result in good yields of tall fescue and interplanted corn under irrigation.