Issue No. 22, Article 3/September 7, 2007
Alternative Uses for Herbicide-Treated Soybean Fields
Dry soil conditions across areas of Illinois have been detrimental to soybean growth. Double-crop soybeans appear to have been particularly adversely impacted, but in some areas even full-season plantings are demonstrating signs of significant stress. Soybean farmers in these drought-affected areas may be considering using existing stands for something other than seed harvest.
Grazing livestock and making soybean hay or silage are examples of alternative uses for soybean. However, if a soybean crop was previously treated with one or more herbicides, the herbicide label may prohibit these alternative uses.
Restrictions on soybean use exist for certain herbicides labeled for soil or foliar applications. For example, the restriction found on the label for Canopy (a soil-applied herbicide) states "do not graze treated fields or harvest for forage or hay," while on Ultra Blazer (a postemergence herbicide), the label states "do not use treated plants for feed or forage." Other product labels have restrictions based on application timing (e.g., Dual II Magnum prohibits grazing or feeding of soybean-treated postemergence, but not if the product was applied preemergence), or they specify a certain interval that must elapse between application and grazing, feeding, and so on (e.g., 14 days must elapse between application of FirstRate and harvesting soybean for forage or hay).
Glyphosate-resistant soybean treated postemergence with glyphosate may be grazed or harvested for livestock feed not sooner than 14 days after application. However, certain glyphosate formulations restrict feeding treated soybean to livestock for 25 days following a preharvest application to non-glyphosate-resistant soybean varieties.
These examples illustrate there is no blanket answer to the question of using herbicide-treated soybean for livestock feed or forage. Before utilizing existing soybean stands for something other than seed harvest, be sure to check the label of any herbicide(s) applied to a particular field.--Aaron Hager