CORN GRAIN YIELD RESPONSES TO TILLAGE SYSTEMS AND PLANT DENSITIES

An increasing shift from conventional systems of tillage to reduced-or no-tillage system has been recorded in many parts of the world. Limited research information is available on the interaction of plant density and tillage systems in corn (Zea mays L.). A two-year field study was conducted to evaluate the grain yield and yield components of corn in response to four tillage systems as plant density increased from 3 to 12 plants m^-2. Tillage treatments were moldboard plowing and disking (PD), chisel-plowing (CP), double disk (DD), and no-tillage (NT). Tillage method did not affect either biomass or grain yield; however, there were tillage effects on some yield components within particular years. Plant density significanty affected grain yield and all components of yield. Kernel number per row showed the highest sensivity to increasing plant density. Interaction of tillage systems and density on grain yield was not significant in 1987 but was significant in 1988. However, the effect of plant density on the grain yield response to tillage system was not considerable. In both years, NT produced slightly higher or equal grain yield as other tillage systems.