Project ID



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.

Principal Investigator(s)

Robert G. Hartzler


Garren Benson, Dennis Shannon

Year of Grant Completion