Cover Crops Are Critical To Keeping Soil Healthy
A colleague, Nicole Kubiczki, recently used her social networking page to share an outreach article she had written to promote the use of cover crops and to encourage farmers to apply for technical and financial assistance in support of cover cropping. Nicole is a December 2015 Penn State graduate where, among other things, she had the opportunity to participate in cover crop research.
Nicole is just starting her career with the USDA Natural Resources Conservation Service (NRCS). Her enthusiasm is contagious and reminds me of the start of my own Soil Conservation Service/NRCS career some 37 years ago.
The Cover Crop Cycle
Then, like now, cover crops were a hot topic. Researchers at my alma mater (Cornell University), along with students, faculty, and staff at many other colleges, were exploring cover-cropping strategies and the benefits and challenges of introducing cover crops into field and vegetable crop rotations. Like so many agricultural best management strategies, enthusiasm for various conservation practices tends to be somewhat cyclical. We are once again at one of the high points in the cover crop cycle, and for good reason.
Cover crop choices can include a wide variety of species alone or in combination. Multi-species cover cropping is one twist in this round of enthusiasm for cover crops. Cover crops are now far more prescriptive, not just a good idea with some minor erosion control benefits. More often these days, the benefits are described in terms of soil health with impacts on soil fertility, leaching and runoff reduction, pollinator and other beneficial insects habitat, increases in organic matter, improved soil tilth, reduced compaction and greater infiltration, disease and weed suppression, etc.
Not all cover crops provide these benefits, and certainly not in every situation or if only used for a season or two. That’s where the prescriptive part comes in and where the current round of research and demonstrations across the country are paying large dividends.
We’re also learning more about some of the possible negative aspects of cover cropping, most of which can be minimized or mitigated with good planning and management. Obviously, not every cover crop species or cover crop mix fits every cropping system. This can be especially true for vegetables where the choice of cover crop species could impact the suitability of the field for the next crop. Further, to maximize cover crop benefits, timing of planting and cover crop termination can both be critical. We’re learning more every day — much of that from the experiences of farmers across the country and around the world.
There are so many possibilities: over wintering traditional cover crops, summer cover crops, cover crops as incorporated “green manure,” season-long cover cropping (full fallow season), interseeded cover crops, and cover crops that (usually) winter-kill. Add in highly prescriptive cover crop management strategies, including close attention to timing of seeding, planting techniques, clipping (or not), desirable or undesirable allelopathic effects (especially from cereal rye), and other factors, and cover cropping can be as complicated as the management of the market crops. Climate and seasonal variables also greatly influence cover choices, impacts, and economics.
Local Cooperative Extension, NRCS and Soil and Water Conservation District staff, as well as seed dealers and crop consultants, can be helpful in planning cover crops. Farmers increasingly look to online resources. That’s certainly a change from when I started my soil conservation work many years ago. For Nicole’s generation, however, it’s often the first stop. Try using your favorite search engine to look for “cover crop decision tool.” You’ll find options customized for every climate zone and many different cropping systems.
I won’t say there’s no place for “clean tillage” in modern agricultural systems. But we’re seeing increasing evidence that, even in moldboard plow based tillage systems, minimizing the amount of time the soil is bare is the key to soil health and environmental protection. I hear Practical Farmers of Iowa are marketing a T-shirt that reads: “Don’t Farm Naked: Plant Cover Crops.” You can find it at PracticalFarmers.org.
Where cover crops can help address resource concerns, financial assistance may be available. Plan ahead though. Contracts might not be approved until the next cropping season and program rules can limit availability of funds if you’ve already been cover cropping. I frequently say, “If it’s really worth doing, it’s worth doing without cost-sharing assistance.” I’m confident that’s true for cover crops.
Nicole ended her outreach article with, “An investment in your farm’s soil is an investment in your farm’s future.” Well said, Nicole. Cover crops can represent a fairly low-cost investment with many and varied benefits when they become part of a long-term cropping system.