Now is the time to make plans for cover crop planting if you have not already done so.
There are several cover crop species that are often talked about. However, cereal rye, oats and radish are the most commonly used cover crops in the region, Iowa State University Extension specialist Mark Licht wrote in an Integrated Crop Management blog post. Hairy vetch, red clover, cowpea, rapeseed, winter wheat, triticale and annual ryegrass all get mentions.
Choosing which to use is dependent on your goals, how and when you are going to plant, and your corn and soybean management practices.
Biomass production is typically associated with soil health, reduced soil erosion and nutrient loss reduction benefits. More biomass production equates to more benefits.
In general winter and spring small grain species provide the most biomass following corn and soybean crops. If seed corn production and corn silage fields are being targeted, there is much greater opportunity for legumes and brassicas to be added into the cropping system for biomass production but also ancillary benefits of alleviating soil compaction or N fixation.
Cereal rye and triticale are the most dependable cover crops to overwinter. Winter wheat, red clover and hairy vetch can overwinter with adequate fall growth and suitable winter weather conditions. Most often the brassica species do not overwinter, but some brassicas have a small percentage of the seed lot that will germinate and grow in the spring.
Nitrogen fixation is limited to legumes, and even then, they need to be planted early and have a good overwintering capability in order to produce enough nitrogen to justify higher seed costs and possible alterations to corn hybrid maturity or harvesting of corn at a higher grain moisture.