Effect of row spacing and seeding rates on soybean yields and weed management programs
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This research studied the influence of row spacing on the competitiveness of soybeans with weeds. Late-emerging weeds were a greater problem in 30-in. than in 10-in. rows, and narrow-row soybeans competed successfully with weeds that emerged three weeks after planting, whereas wider-row soybeans needed four weeks to become competitive. The shading provided by narrow-row soybeans was as effective as a layby cultivation in controlling late-emerging weeds. Moreoever, post-emergence herbicides controlled weeds effectively at rates lower than recommended by the manufacturer. Two one-quarter applications two weeks apart provided control equal to the full amount, with no yield losses. Narrow-row spacing offers potential for reducing herbicide costs, although success depends on appropriate selection and timely application of herbicide.