Weed Management in Soybeans

Weed Management in Soybeans
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Weed management is one of the most important and sometimes one of the most expensive components of a soybean production program. Herbicides are a necessity in profitable soybean production. They are, however, only one component of a weed management program. Weed management is most successful when crop rotation, crop competition, cultivation, and judicious herbicide use are combined in a planned and coordinated program.
Herbicides should be used only as needed and only after careful consideration of the weed problems and the impact the weeds will have on production. Your county Cooperative Extension Center has computer software that can help you determine when weed populations exceed the economic threshold and, hence, help you determine when a post emergence herbicide application is justified. In addition, your Extension agent has software to help you determine the most appropriate soil-applied or post emergence herbicide or combination of herbicides to control the complex of weeds you have. This software is available for individual growers also.

Crop Rotation
Crop rotation should be an integral component of a weed management program. Crop rotation allows the use of different types of herbicides on the same field in different years. This can prevent the buildup of problem weeds and help to keep the overall weed population at lower levels. More important, crop rotation and proper selection and rotation of herbicides are key components in a strategy to avoid evolution of weed resistance to herbicides
Some soybean herbicides may persist long enough to damage certain rotational crops. Before using any herbicide, check the rotational restrictions.

Crop Competition
Crop competition is an effective but often underused weed control tool. The basic strategy is to follow practices that result in rapid soybean growth and canopy closure so as to provide maximum shading of weeds. Soybeans should lap in the row middles as soon as