EFFECT OF RIDGE TRUNCATION ON WEED POPULATIONS AND CONTROL IN RIDGE-TILLAGE CORN (ZEA-MAYS)

Ridge truncation methods affected weed populations, weed control, and corn yields in a ridge-tillage production system. Ridges were left und isturbed, partially truncated, deeply truncated, or destroyed by full- width tillage. The effect of truncation on weed densities and control (visual estimates of biomass reduction) varied by weed species, herbic ide treatment, and time of observation. Without herbicide, deep trunca tion resulted in the lowest densities of all species except giant foxt ail. Band application of herbicide controlled all weed species as well as broadcast application following deep truncation. When herbicides w ere broadcast, weed control was usually not affected by ridge truncati on. Ridge truncation often increased corn yields compared with no trun cation due to better weed control. While deep truncation often resulte d in lower weed populations following herbicide treatment than shallow truncation or disking, differences were not great enough to affect co rn yields. When ridges were truncated, broadcast herbicide did not inc rease corn yields compared with banded herbicide.