Are cover crops beneficial for yields?
Robert Mullen, Ph.D.
Director of Agronomy
To say Dr. Robert Mullen is passionate about agriculture would be an understatement. He holds a Bachelor of Science degree in ag business from Cameron University, along with a Master of Science degree in plant and soil science and a Ph.D. in soil science from Oklahoma State University. In addition, Dr. Mullen has been published in a variety of scientific and trade journals. But it’s not just his academic accomplishments that make him unique. It’s his unwavering ability to take complex data and — in simple terms — explain how it impacts a farmer’s bottom line. Dr. Mullen delivers the kind of insightful observations that can lead to a more profitable business. As a leading agronomy expert, Dr. Mullen has a goal to further educate farmers on best management practices that improve their yields and maximize their return on investment.
This is an often asked question that has mixed results in scientific literature. There is geographic specificity to this answer. In the southeastern U.S., there is some good work that shows growing cover crops in rotation can provide yield increases (especially if you are rotating crop species — legume covers with grasses, grass covers with legumes). Remember though, that cover crops grown in the Southeast have a much longer growing period than cover crops grown at more northern latitudes.
In the Midwest, the yield benefit of cover crops to primary crops is not as consistent. We can find publications where yield increases are reported and others where there is no yield benefit (occasionally there is even a yield drag).
When cover crops are grown is important. Cover crops grown following wheat (more of an Eastern Corn Belt strategy) have a greater probability of providing a benefit than a cover crop that’s grown following a soybean and corn harvest (which becomes even more true as one moves further north). I would recommend consulting local extension personnel or retail agronomists to get guidelines on the right cover crops for your area, and more importantly how to manage them.