Agronomy: Set up success of double-crop soybeans by controlling weeds in winter wheat

Last week I spent time talking with a client about corn planting. But for the most part we really just talked about the weather and how all the rain will delay corn planting. Delayed corn planting due to wet weather usually means that nitrogen and herbicide applications to winter wheat are also delayed. In talking about this delay in addressing the needs of the wheat crop our discussion centered around not getting the nitrogen on the wheat, but also focused heavily on getting an application of herbicide on it, too.

This farmer shared an observation he made last year. In scouting wheat fields they made a decision, based solely on the presence of wild garlic, whether to treat or not treat those fields with a herbicide. Those fields that had wild garlic would get treated, those that did not have wild garlic would not. Unfortunately, this led to several fields not getting treated.

As the crop pushed towards maturity he noted that the fields that weren’t treated began to get “rough,” as he put it. A large amount of broadleaf weeds, particularly waterhemp and marestail, began to show through the golden wheat. As harvest progressed he observed in most cases there was little or no yield difference between the treated and non-treated fields due to these weeds. However, they were cutting off a lot of those broadleaf’s with the combine head during harvest.

More importantly, these weeds caused them to change their planned herbicide program on those fields. They now had injured weeds that were harder to kill and thus required a different control method. In some fields those injured weeds never did die completely and competed with the double-crop beans.
This year they changed their scouting criteria; not only were they looking for wild garlic, but also waterhemp, marestail and other broadleaf weeds in an effort to control them and help their double-crop beans by eliminating this competition.

There are many steps to a successful double-crop soybean program. Weed control beginning before the beans are ever planted is one of those necessary steps and getting it right in wheat also means getting in right in the following soybean crop. How are you addressing potential weed issues in your winter wheat?

Kelly is serving as the Illinois Soybean Association Double-Crop Specialist. He was raised on the family farm in Benton, Illinois and graduated from Southern Illinois University (SIU)-Carbondale with a BS in Agriculture Education and Mechanization, and a Masters of Science (MS) in Plant and Soil Science.  During the last thirteen years he has been involved with on-farm precision ag research dealing with the use of historical yield maps as predictors for variable rate corn populations, variable rate nitrogen, variable rate phosphate and potash and tile drainage.  He has experience working with RTK elevation data to create within field watersheds and wetness indexes to determine relationships between crop inputs, drainage and yield. Kelly has spent 25 years as a soil fertility agronomist and precision agriculture consultant in southern Illinois while also spending 4 years as a Farm/Agronomy Manager and GIS Coordinator for a large farm in southeastern Illinois. In 2012 Kelly and his wife Lori started Precision Crop Services in Benton where they provide agronomic services for their customers including soil testing, crop scouting, data analysis and GPS/GIS services. He is a Certified Professional Agronomist and a Certified Crop Advisor.