Prospects for weed control through crop interference

Crop interference, entailing weed suppression, should be distinguished from crop tolerance of weeds, ie relatively small yield loss due to the presence of weeds. Tolerance may lead to increases in weed seed populations that can cause future yield losses. Interference should occur as early as possible in growth to prevent resource consumption by weeds. A path analysis of crop-weed interference is presented. The model can be used to estimate the relative magnitude of early vs. later crop interference with weed growth, and to identify crop traits that contribute to interference with weed growth. Such analysis can identify crop varieties that show strong early interference with weed growth, and traits associated with strong early interference. For illustrative purposes, the model is applied to characterize differences among soybean varieties in interference with common cocklebur Xanthium strumarium. Weed control by crop interference could be enhanced by crop breeding and management. -from Author