When corn has been harvested there are usually a couple months of growing season left. Pigweed, among others weeds, can really flourish once the corn is gone and no longer competing for light, water, and nutrients. The photo below shows a field that was harvested about a month ago.
The atrazine, glyphosate, and metolachlor that were put out when the corn was young are long gone and with the corn no longer shading the ground, the pigweed is thriving. Think about all that weed seed that’s going into the soil that we will be battling next season. One method for managing these weeds that some growers are trying is planting a summer cover crop.
The field in the photo above was planted just a couple days after the corn was harvested. It came up quick and is about a month old now. It won’t be long before it is shading the ground. There are a few weeds present, though they are few and far between. Nothing like the field in the first photo of this post. This is a multi-species cover crop including sorghum-sudangrass, sunflowers, radish, peas, millet, and sunnhemp. You can make some of them out in the photo below.
A summer cover crop can be terminated later in the fall, rolled down, and wheat will be planted into it. Planting a cover crop does add some expense, but it can save some expense later in the season. Once it is rolled down, it will create a mat that will prevent a fair amount of weed seed from coming up. That may reduce the need for herbicides later in a wheat crop. In addition, there is a good chance we will see less pigweed in the following soybean crop since the cover crop didn’t allow them to grow up without any competition.
Weed suppression is one of the most attractive attributes that we are seeing with cover crops. For another example of this, take a look at this post from 2016.