|Johnson, William - UNIV OF MISSOURI|
Submitted to: North Central Weed Science Society US Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: December 5, 2002
Publication Date: N/A
Technical Abstract: The impact of season-long interference by mixed populations of weeds grown in bands either only in corn rows (IR) or only between rows (BR) on corn yield has not been reported before. Over three years in Missouri, the ranking of corn yields in response to four weed interference treatments were as follows: (IR + BR weed-free)>=(IR weedy)>=(BR weedy)>=(IR + BR weedy). In all three years, (IR + BR weed-free) yields exceeded those for either the (BR weedy) or (IR + BR weedy) treatments, the two lowest yielding treatments. In two of three years, yields for the (IR + BR weed-free) treatment were greater than the (IR weedy) treatment, but these two treatments were indistinguishable in a third year. In two of three years, the yields for the (IR weedy) treatment exceeded the (BR weedy) treatment, but these treatments were indistinguishable in a third year. Finally, the yield of the (BR weedy) treatment was indistinguishable from the (IR + BR weedy) treatment in two of three years. In a third year, the yield of the (BR weedy) treatment exceeded that of the (IR + BR weedy) treatment. The ranking of the four treatments in terms of the between row total or grass weed ground cover, chiefly giant foxtail, was inversely related to the corn yield ranking. When bands of weeds grew in crop rows, but were controlled between rows, corn yield partially compensated for weed interference better than when weeds were controlled in crop rows, but not between rows. This research suggests that it may be more critical to control weeds between corn rows than in rows, but controlling weeds both in and between corn rows maximized yield.