By Scout Nelson
Post-emergence herbicide applications are an important part of soybean weed management. To achieve effective weed control, many herbicides require the use of adjuvants. These products help improve herbicide performance and reduce application-related risks under different weather and field conditions.
Sithin Mathew, Weed Science Graduate Student, Eric Yu, UMN Extension Crops Educator, and Debalin Sarangi, Extension Weed Scientist, explained that adjuvants help optimize herbicide applications by improving spray retention, spreading, penetration, and absorption on target weeds. Although some herbicides contain built-in adjuvant systems, additional products are often needed to achieve the best results in specific environments.
Adjuvants commonly used in soybean herbicide programs fall into four main categories. These include activator adjuvants such as nonionic surfactants, crop oil concentrates, and methylated seed oils; water conditioners such as ammonium sulfate and volatility reduction agents; spray solution modifiers including antifoam and drift reduction products; and adjuvant mixtures that combine several functions.
Using the correct adjuvant is important because the wrong product or rate may reduce weed control or increase the risk of crop injury. Herbicide labels provide guidance on the type and amount of adjuvant required for each product. Farmers should carefully review all herbicide labels, especially when multiple products are mixed in the spray tank.
Many widely used soybean herbicides require specific adjuvants. Products such as Roundup PowerMax, Liberty Ultra, Enlist One, Enlist Duo, FlexStar, Cobra, Pursuit, Raptor, Select MAX, and others may require nonionic surfactants, crop oils, ammonium sulfate, or other additives to maximize effectiveness. Some herbicides also contain restrictions on mixing certain products, making label review essential.
Water conditioners such as ammonium sulfate are frequently recommended because they improve herbicide performance in hard water and help increase weed control. Drift reduction and volatility reduction products may also be required for certain herbicides to reduce off-target movement.
Successful soybean weed management depends on selecting the correct herbicide, using the proper adjuvant, and following all label instructions. Careful planning and proper application practices help improve weed control, protect crop health, and support better soybean production throughout the growing season.
Photo Credit: istock-sandramatic
Categories: Minnesota, Crops, Soybeans