Plan to Terminate Cover Crops

Cover crops in a field.

Cover crops can provide a variety of benefits, but if you don’t terminate them well they could limit your cash crop’s success. There is more than one way to eliminate a cover crop, consider your options and find what’s best for your fields.

The three methods used for termination include herbicide, tillage or rolling/crimping, according to Iowa State University (ISU).

Consider your cover crop type before selecting a herbicide. Crop species and growth stage will determine your herbicide’s success, ISU research suggests.

Some species are easier to kill than others. Winter wheat, annual ryegrass and red clover can prove more challenging to kill since they often have a dense canopy and mature rapidly—which can cause herbicide failure.

By understanding your cover crops you’ll be better equipped to select a herbicide—contact or translocating. Contact herbicides require thorough coverage since they only affect the part of the plant they touch. Whereas translocating herbicides don’t require as much coverage since they move and attack the growing point of the plant. In both cases it’s important to apply adequate rates.

Tillage can be a good alternative when herbicides aren’t an option. Since some farmers prefer not to use herbicides or Mother Nature doesn’t provide the right conditions for application, tillage is an alternative. Tillage can destroy the cover and integrate the biomass into the soil while preparing the seedbed.

However, USDA Natural Resources Conservation Service is asking farmers to rethink using tillage as a termination method.

“These farmers [considering tillage] are concerned the cool, soggy spring may reduce the plant’s ability to absorb the chemicals,” says Barb Stewart, Iowa state agronomist with NRCS. She adds that those wet conditions could cause compaction and soil structure damage if farmers choose tillage over herbicides.

Watch for doubled benefit when using rolling/crimping for termination. Using the rolling or crimping to control cover crops could provide additional benefit beyond just killing the cover. Since tall cover crops can shade cash crops, rolling over them could reduce that competition for light.

ISU reminds your cover crop dictates how well rolling or crimping will work. They say that cereal rye (after it has shed pollen), hairy vetch (at full bloom), barley and triticale are good candidates for rolling.

Don’t hurt your chances at a successful cash crop by not caring for your cover crop appropriately. Make your termination plan for this spring.

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