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ARS Home » Plains Area » Brookings, South Dakota » Integrated Cropping Systems Research » Research » Publications at this Location » Publication #301114

Title: A cultural system to reduce weed interference in organic soybean

item Anderson, Randal

Submitted to: Renewable Agriculture and Food Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/25/2014
Publication Date: 6/26/2015
Citation: Anderson, R.L. 2015. A cultural system to reduce weed interference in organic soybean. Renewable Agriculture and Food Systems. 30:392-398.

Interpretive Summary: Organic producers are concerned that extensive tillage may be damaging their soils. They are interested in alternative weed control strategies that may reduce the need for tillage. In this study, we demonstrated that a management system comprised of several cultural tactics can manage weeds effectively in the interval between a cool-season crop and soybean. This system may eliminate the need to till for controlling weeds in this time frame. Not only were weeds controlled, but soybean yielded 14% more in the cultural system than in the conventional tilled system. Our long-term goal is to develop a continuous no-till rotation for organic farming, and this cultural system will contribute to that goal.

Technical Abstract: Organic producers are seeking alternative tactics for weed control so that they can reduce their need for tillage. In this study, we examined cultural strategies during the transition from a cool-season crop to soybean for suppression of weeds. The study was arranged as a three-way factorial, with factors being choice of cool-season crop, till or no-till, and presence or absence of cover crops following harvest of the cool-season crop. The cover crops were oat plus oilseed radish. The conventional practice of several tillage operations to control weeds was also included as a treatment following each cool-season crop. Soybean was planted the following growing season. Each soybean plot was split into 2 subplots: weed-free and weed-infested. Weeds were controlled in the weed-free subplot with herbicides and hand weeding. One cultural system comprised of oat/pea as a preceding crop, cover crops, and no-till, reduced weed biomass 63% compared to the conventional system. Consequently, soybean yielded 14% more in this treatment than with the conventional system when weeds were present. This was the only cultural system that performed better than the conventional system. Integrating several practices into a cultural system can suppress weeds effectively and may eliminate the need for tillage during the interval between cool-season crops and soybean. This approach will contribute to development of a continuous no-till system for organic farming.