EVALUATION OF WEED CONTROL STRATEGIES IN ORGANIC SOYBEAN PRODUCTION

Authors: KLUCHINSKI, DANIEL - RUTGERS UNIVERSITY; Singer, Jeremy

Submitted to: Crop Management at www.cropmanagement.org
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/2005
Publication Date: 6/14/2005
Citation: Kluchinski, D., Singer, J.W. 2005. Evaluation of weed control strategies in organic soybean production. Available: Crop Management doi:10.1094/CM-2005-0614-01-RS.

Interpretive Summary: A 2-yr study (2001 and 2002) in soybean under organic production evaluated row width, mechanical weed control equipment, cultivation frequency, timing, on annual broadleaf and grass weed control and grain yield. Weed control was higher and yields were generally greater in wide row widths. Excessive rainfall reduced rotary hoeing timeliness and effectiveness, and soybean yield. Yield in narrow rows with 2 rotary hoe passes were low or lowest of all treatments each year. Plant density reductions were numerically highest in rotary hoe treatments, ranging from 19 to 28% compared to hand-weeded controls. The highest yielding treatments varied but included use of a cultivator. These results indicate that wide rows improve weed control and produce higher yields than narrow rows in organic soybean production.

Technical Abstract: A 2-yr organic soybean [Glycine max (L.) Merr.] study (2001 and 2002) evaluated row width (narrow 8 inch and wide 30 inch), mechanical weed control equipment (rotary hoe and cultivator), cultivation frequency (1 to 3 passes with one or both implements) and cultivation timing (early, late or sequential) on annual broadleaf and grass weed control and grain yield. Broadleaf and grass weed control was successful with most treatments but control levels were lower in narrow row (NR) systems. Timing cultivations either too early or too late due to excessive rainfall or time constraints may reduce rotary hoeing (RH) effectiveness. Weed control and yields were generally greater in wide row (WR) treatments. Yield in NR with 1 or 2 RH passes was lower than most other cultivated treatments in 2002; however the mechanical control practices did not significantly affect plant population in either year. Often the best weed control and highest yielding treatments included use of a cultivator (C). Although yields were not significantly different in 2001 among treatments, in 2002 the highest yields were achieved with WR C treatments compared to NR, 1 or 2 RH treatments.