ARS | Publication request: CULTURAL AND MECHANICAL WEED CONTROL METHODS FOR ORGANIC SOYBEAN PRODUCTION

Submitted to: National Association of County Agricultural Agents Proceedings
Publication Type: Abstract
Publication Acceptance Date: July 15, 2004
Publication Date: July 15, 2004
Citation: Kluchinski, D., Singer, J.W. 2004. Cultural and mechanical weed control methods for organic soybean production [abstract]. National Association of County Agricultural Agents Proceedings. p. 41-42.

Technical Abstract: Weed control is often the biggest challenge facing farmers transitioning to or practicing organic production. A two-year study (2001-2002) evaluated row width (narrow 8 inch, wide 30 inch), tillage equipment (rotary hoe, Buffalo cultivator), tillage frequency and type (1 to 3 cultivation with one or both tillage equipment), tillage timing (early, late or sequential), and cover crop residue (rye) on weed control in soybean under organic production methods. Annual weed control was higher in wide row plantings (rated fair to excellent) than narrow rows (rated poor to fair). Yields averaged 44 bu/A in wide row plantings both years versus 42 and 32 bu/A, respectively, in narrow rows. Yields were significantly lowest in narrow row soybean with two passes of a rotary hoe due to reduced soybean populations; wet weather reduced the implement effectiveness and weed control. Highest yields due to excellent weed control without soybean population reductions occurred in wide row soybean in 2001 with a single pass of a cultivator (49.4 bu/A) and in 2002 with one pass of a rotary hoe and two passes of a cultivator (53.9 bu/A). Rye residue provided only 4% control of broadleaf weeds and 0% control of grass weeds in 2001 but 88% control of broadleaf and 82% of grass weeds in 2002. The residue significantly reduced soybean populations both years but yields (45.9 and 38.9 bu/A) were comparable to other tillage-based treatments. Weed control in organic soybean production requires successful integration of cultural and mechanical practices, and diligent planning, observation and management.