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Cover Crop Calculations

Image by Matthew Wilde

Growers prescribe to many practices to improve soil health on their farms.

Remedies certainly differ, but all have one thing in common: they must make sense economically. Without the proper return on investment, a promising treatment is quickly discarded.

Cover crops are one prescription getting a close look from many farmers. The latest Census of Agriculture shows cover crops were seeded on 15.4 million acres in 2017. That’s a 50% increase since 2012.

Despite impressive growth, concerns about stand establishment, terminating a cover crop and most importantly, cost, deter farmers from trying the practice. Results from a recent USDA-Sustainable Agriculture Research & Education (SARE) report may alleviate some of those worries. It uses yield and economics data from five years of national cover crop surveys to try to answer a farmer’s most pressing question: When do cover crops pay?

“Cover Crop Economics: Opportunities to Improve Your Bottom Line in Row Crops” explored several management situations that can affect how quickly cover crops provide a positive net return. The quickest paybacks--one or two years--occurred:

> when herbicide-resistant weeds are a significant problem

> when cover crops are grazed, assuming there’s fencing and water already available

> when soil compaction takes place.

Waverly, Iowa, farmer Mark Mueller readily admits he took a leap of faith regarding potential economic returns when he first started trying cover crops. But he’s banking on soil health benefits paying out over the long run. “I don’t need to have the highest yield per acre, but I do need to make the most money per acre. I think I’m on track to do that with no-till and cover crops.”

The report shows he may indeed be on the right path. After five years of cover crops, corn yields increased 3% and soybean yields 5%. In the drought year of 2012, there was a significantly bigger yield boost from cover cropping on the majority of farms responding to the survey. Corn yields increased by 6% and soybeans by 11.4% after one year of cover crop use.

The bushel boost was attributed to impacts on rainfall infiltration, reduced soil evaporation from cover crop residue, potentially deeper rooting of the row crops and changes to soil biology such as increased mycorrhizal fungi. These fungi allow plants to draw more nutrients and water from the soil. They also increase plant tolerance to environmental stresses and play a major role in soil aggregation process and stimulate microbial activity.

Today’s tight margins may prevent some growers from making the initial investment in cover crops (the survey used a median value of $25 per acre for seed and $12 per acre for seeding) and taking a longer point of view on the potential financial rewards of cover crops.

The bottom line of cover crops, of course, is the bottom line. Rob Myers, the lead author of the report and SARE program director at the University of Missouri, points out: “Thousands of farmers are finding the profitability benefits of cover crops on their farm do improve over time. It’s not unlike how applying ag lime can take 2 to 3 years to pay, or buying a new piece of equipment can take a few years to cash flow.

“However, if producers use cover crops to address problems specific to their farm, such as weeds, fertility, erosion or compaction, they can quickly gain cost efficiencies. The cover crops also provide a management tool to make soils more resilient to excessively dry or wet weather while building towards long-term improvements in profit.”

Write Gregg Hillyer, 2204 Lakeshore Dr., Suite 415, Birmingham, AL 35209, or email gregg.hillyer@dtn.com.