Jun 30, 2021
How to make your cover crops work for you
Nic Podoll

At the Rodale Institute, we know that cover crops provide amazing benefits such as reducing pest and weed pressure, enhancing soil and water quality, increasing nutrient cycling efficiency, and providing nutrients to cash crops.

But how does the everyday grower evaluate whether his or her cover crops are providing those benefits?

Come planting season, most farmers find themselves standing in their fields asking the question, “Did my cover crops work or not?” If you have struggled with cover crops, the task of evaluating their successes, their failures, and potential corrections may have seemed too daunting to attempt.

There is a lot of literature on cover crops and trials conducted by Rodale Institute, universities and other organizations that are a great place to start. Ultimately, however, nothing can replace the experience of planting cover crops on your own farm. Once you have made that investment, you need to make sure you get the most out it, whether it’s learning from failure or replicating success. That’s where evaluating cover crop performance comes in.

The first step of evaluating your cover crop success is establishing a system.

Begin by thinking about what you want cover crops to do for you. What challenges are you facing on your farm? How might cover crops address those challenges? Write those down and then develop a set of goals for cover crops in your operation. For example, a common goal for all operations is weed suppression. Once you have your overarching goals that you would like to achieve with cover crops, you can begin to build your cover crop plan.

Next, think about the ways to achieve your goals, and which cover crops have the qualities you need. Using the example of weed suppression, cover crops with qualities like quick emergence, vigorous growth, full ground cover, good stand quality, and a high biomass come to mind. Any allelopathic effect is also desirable. Also, make a list of variables that may affect cover crop performance in suppressing weeds. This may include variety, seed quality, insect and disease resistance, seeding rates, soil moisture levels and soil fertility. Identifying these criteria to meet your goal of weed suppression will help you decide which cover crops to plant.

Once you have chosen your cover crops, the next step is to measure their success in the field, using the criteria you identified. I recommend developing some sort of rating scale. It could be as simple as assigning each cover crop a 1-5 rating in achieving each criterium.

Make notes about each rating based on the possible variables that could have affected performance. For example, maybe you did not achieve very good stand quality and it had a negative impact on the cover crop’s ability to suppress weeds. Investigate why this occurred, and whether it can be attributed to a failure of that cover crop species or a variable that affected its performance.

In this example, high moisture levels or low seed quality could have led to decreased germination rates. After evaluating performance and considering all the variables, you will have a much clearer picture of what decisions you need to make next time to achieve better outcomes.

Your cover crop evaluation system can be as simple or as complex as you need it to be, but it should make sense to you and be based on the specific conditions present on your farm. You want to end up with clear goals and performance criteria that help you choose which cover crops to plant and when. This should also be an evolutionary process, in which you not only continuously refine your cover crop selections, but also the performance criteria you measure them against.

Start with as simple of an evaluation system as possible. As you evaluate cover crop performance and you gain more experience with cover crops in your farming system, your evaluation system will naturally evolve and become more advanced over time. You will discover and add new variables that affect performance. You may realize that certain performance criteria carry more weight than others in terms of achieving the overall goal they are attached to. Consider ways to incorporate those discoveries into your evaluations.

A cover crop evaluation plan should help make things easier, not harder or more stressful. Always keep in mind that the goal of the evaluation process is to help you fully integrate cover crops into your crop rotation and enhance the cultural controls of your farming system so that you can make cover crops work for you and achieve the full potential of benefits to your soil and your bottom line.

Need help evaluating your cover crop performance, planning your crop rotation, or drafting a systems plan? Rodale Institute’s Organic Farm Consulting Services can help you with your transition to organic or regenerative practices. Services may be provided free of charge to farmers in Pennsylvania and the Midwest. Contact us at Consulting@RodaleInstitute.org or at 610-683-1416 to learn more.

Nic Podoll is a Midwest Organic Consultant with Rodale Institute. Nic is a lifelong organic farmer, having grown up and farmed with his family on their certified organic farm in southeast North Dakota, raising small grains and vegetable seed. Nic is IOIA certified in crops and holds a Master’s in Agricultural & Extension Education from North Carolina State University. He is located in north-central Minnesota.

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