Submitted to: Weed Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 19, 1997
Publication Date: N/A
Interpretive Summary: Conservation tillage crop production systems reduce soil erosion, conserve soil moisture, and reduce energy use; but often increase weed control problems. Conservation tillage consists of reducing or eliminating soil tillage before crop planting. This alters the environment where crops, weeds, and weed control practices interact. Understanding the influence of tillage systems on weed populations and control will help the development of more effective weed management systems that require less herbicide. Ridge tillage is a conservation tillage system that results in unique soil disturbance patterns that may affect weed population development. This includes partially leveling and rebuilding soil ridges each year. The purpose of our research was to determine the effects of ridge truncation at crop planting on weed populations and subsequent control. We found that deeply truncating the ridges while not disturbing the interrow area reduced weed populations compared with other truncation methods. Deep truncation also improved the effectiveness of banded herbicide application (treating only 50% of the soil surface as opposed to 100%) compared with no truncation, shallow truncation, or full width tillage. The combination of deep truncation with banded herbicide reduced herbicide use while maintaining weed control and corn yields compared with more conventional tillage practices. When ridge tillage is used, changes in ridge management may be used to improve weed management. These results will help farmers develop practices that reduce soil erosion while reducing herbicide use.
Technical Abstract: Ridge truncation methods affected weed populations, weed control, and corn yields in a ridge-tillage production system. Ridges were left undisturbed, partially truncated, deeply truncated, or destroyed by full-width tillage. The effect of truncation on weed densities and control varied by weed species, herbicide treatment, and time of observation. Without herbicide, deep truncation had the lowest densities of all species except giant foxtail. Deep truncation resulted in the greatest percent control for all weed species following herbicide application. Band application of herbicide controlled weeds as well as broadcast following deep truncation. When herbicides were broadcast, weed control was usually not affected by truncation. Ridge truncation increased corn yields compared with no truncation due to better weed control. While deep truncation often resulted in lower weed populations and better weed control than shallow truncation or disking, these differences were not great enough to affect corn yields. When ridges were truncated, broadcast herbicide did not increase corn yields compared with banded herbicide.