By Don Donovan

Farmers are asking each other questions such as: Are you using cover crops? What species are you using? Have you tried mixes? Have you tried planting green?  

Indiana had nearly 1 million acres of cover crops in 2018, and cover crops are now the third largest crop in the state. Some farmers asking questions are ready to plant into high-biomass covers. They’re using a roller crimper to terminate the cover and put the biomass on the soil surface.

Those using roller crimpers do so for several reasons. The primary purpose is terminating certain cover crop species such as cereal rye or hairy vetch. Organic farmers use roller crimpers to terminate cover crops, but now non-organic farmers are finding benefits, too.

Kill without herbicides 

Once cereal rye reaches full maturity and drops pollen, it can be terminated with the pass of a roller crimper. If termination isn’t obtained, a light rate of herbicide completes the process. 

If you’re new to cover crops, you might ask why it matters if you roll the cover crop down onto the soil surface. Long-term users find many benefits to having cover crop residue on the soil surface. The heavy mat of cereal rye residue prevents sunlight from reaching the soil surface, thereby preventing many weed species that depend on sunlight to germinate from doing so. This mat of residue is very effective in helping control some difficult weeds, such as marestail and waterhemp. They need sunlight to germinate. 

Midsummer in Indiana usually means periods of dry weather, which can lead to crop stress and decreased yield. A heavy mat of terminated cereal rye cover crop will protect the soil surface, decreasing evaporation and keeping more moisture in the soil. This little bit of extra moisture may be enough to keep your crop from being stressed, thereby fending off yield loss.

That adage of “What is a half-inch rain worth in July or August?” is true. It may mean the difference between breaking even and making a profit. Protect your soil with a mat of cover crop residue.

Other benefits

A mat of terminated cover crop residue also protects soil from excessive temperatures during the hot weeks of summer. Soil temperature can differ by 20 to 25 degrees F between protected soil and unprotected soil. 

Why does this matter? Plant roots and soil microbiology like relatively constant living conditions, moisture, temperature and soil oxygen levels. Microbiology especially doesn’t like extremely high temperatures. 

That microbiology is the mechanism that converts nutrients into a form for plant roots can take up. When the soil gets hot, the microbiology either shuts down or moves deeper to cooler soils. No microbiology and no available nutrients mean a stressed plant and less yield, which means less potential profit. Again, that mat of terminated cover crop may be the difference between a breakeven yield and a profit.

For more information on use of a roller crimper in your operation, contact your local soil and water conservation district or Natural Resources Conservation Service office. Take that next step in your soil health journey!

Donovan is a district conservationist with NRCS. He writes on behalf of the Indiana Conservation Partnership.