INFLUENCE OF WEED DENSITY AND DISTRIBUTION ON CORN (ZEA-MAYS) YIELD

The impact of weed density and weed distribution on irrigated corn yield was investigated in Colorado, Weed densities examined were 0, 33, 50, or 100% of the indigenous weed population, A series of weed distribution treatments were achieved by varying the length of the weed-free and weedy zones within the corn row while maintaining a constant weed population of 33 or 50% of the indigenous weed level, Grain yield was affected by weed density, but not by weed distribution, Each additional weed reduced corn yield 8.5 and 2.3 kg ha(-1) in 1991 and 1992, respectively. When corn yields were estimated with a computer weed/corn management model, weed densities 5 to 8 wk after planting provided a better yield reduction estimate than weed densities immediately before harvest.