While many growers realize the long-term benefits of cover crops for their soil, justifying an extra $30 to $35 an acre may be difficult in the short term. How do you make cover crops pay without an immediate return on investment with a grain sale?
Speaking at the recent Conservation Cropping Seminar in Springfield, Illinois, Sarah Carlson, strategic initiatives director for Practical Farmers of Iowa Cooperators’ Program, presented seven tips for making cover crops pay:
1. Be cautious about how much you spend on seed.
Cover crop seed can become expensive quickly, especially with more exotic choices like radishes or “fancy mixes.” If you have never planted cover crops before, start with a cereal grain like rye, oats, wheat or even mustards.
Carlson recommends starting with oats into soybeans because the cereal grain effectively reduces nitrates in the soil and will be terminated by winter freezing.
2. Control herbicide costs.
Take advantage of cover crops in your herbicide program. Covers can help control weeds by suppressing winter annual weeds and reduce the need for a full herbicide program in the spring.
Practical Farmers of Iowa compared yields of soybean crops that followed an early termination (10 days prior to planting) with soybean yields that followed late termination (one day prior to planting) of cover crops. Carlson reported that late termination yielded the same or even a bit better than early termination. In addition, the growers were able to reduce herbicide program costs by taking advantage of a longer season of cover crop growth.
3. Avoid cover crop failures.
Beware of residual corn herbicide affecting the cover crop. Preemergence herbicides that persist in the environment may remain in the soil at the time of cover crop establishment in the fall. This can cause a stand failure.
Some herbicide rotational crop recommendations may not be labeled with cover crops in mind so do your research before planting. The relatively short time between cover crop planting and the onset of cool temperatures increases the risk of residual herbicide damage.
4. Avoid redundant expenses.
Carlson suggested growers consider removing one of their nitrogen applications, since cover crops can act as a nitrogen stabilizer and keep nutrients in the soil. A fall nitrogen application with cover crops saw a 42 percent reduction in nitrates leaching into drainage water. Spring nitrogen application with a cover crop saw a 50 percent reduction in leaching nitrates versus just the spring application.
5. Avoid corn yield drag.
If corn is in the crop rotation, keep your profits up by avoiding a yield drag. Be especially careful with nitrogen if you plant rye before corn.  Cover crop residue will immobilize any available nitrogen during the decomposition process. Make sure your corn has enough nitrogen following the cover crop to compensate for tie-up. Apply sufficient nitrogen at planting or terminate your cover crop earlier.
Planting rye before soybeans is easier because soybeans fix their own nitrogen and won’t be affected by immobilization. Additionally, beware of possible soil-borne disease pressure in corn seedlings caused by pathogens hosted in winter cover crops like rye.
6. Improve soybean yield.
The long-term soil health benefits provided by cover crops can increase soybean yields over time. Carlson showed that cover crops improved soybean yields in eight out of 29 trials. In 19 cases yields were neutral and in two cases cover crops caused a yield drag. Carlson explained that one of the reasons for the yield drag could have been the cover crop was too tall before it was terminated.
7. Feed cover crops to livestock.
Grazing cover crops in the fall or spring can reduce the need for stored forages or pasture for livestock. Haying or ensiling the cover crop for later feeding is also another way to gain additional revenue from the cover crop.
There are a lot of opportunities for improved stewardship and healthier soils when adopting cover crops. Follow Carlson’s tips to take advantage of these benefits. The best way to determine if cover crops will make your farm profitable is to set up trials on your own operation.
For more information about cover crops visit: https://practicalfarmers.org/category/blog/.

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