With a late harvest and very minimal tillage accomplished this past fall, there could be a strong case for spring herbicide burndown to allow for clean fields during soybean planting. Many of the winter annual species emerged during the fall and will grow aggressively in warm spring temperatures. A field can look clean now but get out of control very fast, causing issues with soil temperature, soil moisture and jeopardizing seed to soil contact.
Here are a few tips that can make your 2020 spring burndown a little smoother:
1. A good burndown needs to eliminate the key broad leaf weed species. In order to do this, one must have a good broad leaf herbicide such as a dicamba or a 2,4-D load. In many cases, a burndown relies solely on glyphosate as the only option. This could be a very risky recommendation for some weed species, due to glyphosate resistance.
Some Key Winter Annual Weeds to watch for:
- Purple deadnettle
- Yellow rocketcress
- Field pennycress
2. With so many herbicide trait options built into modern soybean seeds, it’s important to match the growth regulator to the bean or at least be aware of how to manage around it.
In my experience as a CCA, I have seen non-dicamba soybeans need replanting due to stand establishment issues caused by a dicamba growth regulator herbicide that was used two weeks prior to planting. The takeaway is to know what products are being sprayed, know the soybean herbicide trait and know the plant back restriction.
3. In the name burndown, it does what it says: burns down the current vegetative weed species. But what about the next flush of weeds, the spring weeds? The answer can be residual products that are strongly recommended to be used in a burndown situation. The residual will help provide a barrier for the next flush of weeds to emerge. This is very important to not only keep a newly emerged soybean protected, but also can keep the field clean during non-controllable, late planting situations.