Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 2/12/1998
Publication Date: N/A
Technical Abstract: Two field studies were conducted in Boone County, IA to compare the effectiveness of weed control recommended by a bioeconomic model to that of standard-herbicide practices. The studies differed in cropping system but used the same treatments, which included long-term histories of various crop management practices. Treatments were applied 3 years in a continuous corn cropping system and 4 years in a soybean/corn rotation. The model recommends PRE and POST treatments based on weed seed bank size and seedling densities, respectively. Numbers of seeds in the weed seed bank were reduced by standard-herbicide compared to model-based weed control. In continuous corn, variations among model-based weed control treatments applied to plots with different crop management histories were eliminated over time. After applying PRE treatments for the third year, relative abundance of foxtails was 98% in model-based compared to 70% in standard-herbicide weed control treatments. In the 2 years corn was planted in the soybean/corn rotation, control of the dominant forb weed species by model-based PRE treatments was greater than that by standard-herbicides, but common cocklebur escaped model-based weed control in reduced tillage treatments that were chisel plowed, reducing yields in the last 2 years.