My introduction to cover crops came from my dad in the late 1960s, while I was growing up on our family grain farm in central Illinois. My dad was primarily growing corn and soybeans at the time, but he also grew some winter wheat that he would inter-seed with a cover crop of sweet yellow clover in early spring. After the wheat was harvested for market, the small clover plants took off, growing rapidly and forming a lush layer of vegetation by fall. The clover would be left untouched in order to protect and improve the soil until the following spring, at which point it would be turned under as a green manure–a crop grown specifically to fertilize the soil–with a moldboard plow, before disking and preparing the field for corn planting.

One time when we were out in the fields, my dad pointed out a plot of corn that had been grown after the clover cover crop and remarked on how much better it looked than the adjacent plot, where there had been no cover crop; the corn’s leaves were a darker green, and its ears were more robust. Further, while my dad was noticing the corn’s superior health following the clover cover crop, I was noticing something else: a greater-than-usual number of rabbits, foxes, hawks, quail, pheasants, and other animals that attracted my attention as an outdoors-loving kid. Those clover fields ended up being my preferred place to spend time tromping around with my dog, because they held the most fascinating diversity of life out of anywhere on the farm.

Although my dad believed in the benefits of cover crops, as crop prices changed in the 1970s, he stopped growing wheat, and thus the sweet yellow clover cover crop disappeared from our rotation. The other factor that had motivated my dad to use cover crops was our elderly landlord, who had done most of his farming in the era prior to World War II when synthetic fertilizers were expensive and not as commonly used. This landlord, Harry Griswold, had farmed with cover crops for decades in the first half of the 20th century, and had always encouraged my dad to keep at least 10%-20% of the farm in legume cover crops to improve the soil. After Mr. Griswold’s passing and the change in markets, cover crops left our farm for almost 40 years, not returning until 2013 when our current tenant, Cory Ritter, started using them again. After Cory got a few years of experience with cover crops on a small acreage, he expanded their use to all the land my mom still owns, with support from a Natural Resources Conservation Service (NRCS) Environmental Quality Incentives Program (EQIP) 3-year contract that provided funds to pay for the cover crop seed. My dad passed away in late 2014, but had given his blessing to the return of cover crops to the farm after attending a cover crop workshop put on by the Soil and Water Conservation Society.

In the meantime, I had gone on to study crop and soil science in college and graduate school. In 1989, I accepted a faculty position in agronomy at the University of Missouri to work on diversified cropping systems. With graduate student John Fisk, I studied the impacts of several different cover crop species on various row crops in the early 1990s. At the time, very few farmers or researchers were paying any attention to cover crops; I remember a time in 1993 when we organized a meeting for other people at the university who we thought might be interested in cover crops, and only a few of them joined us (I repeated that effort in 2014 with considerably more success–over 120 people from the university and state agencies attended the meeting, reflecting the remarkable growth of interest in cover crops).

In early 1995, I went to work at the United States Department of Agriculture (USDA) headquarters in Washington, D.C. as the National Program Leader for Sustainable Agriculture. One of the most enjoyable aspects of that job was meeting farmers from across the U.S. who were working to improve the sustainability of their farming operations, and having the privilege of visiting dozens of their farms. Some of those farmers were using cover crops and enthusing about their ecological and economic benefits. For example, Steve Groff, a farmer in Pennsylvania, was an early cover crop advocate whom I met in 1995 and has since had a big impact on me. Steve’s expertise and passion for cover crops grew so strong that he became one of the most sought-after cover crop speakers around the world, and his family farm has arguably been the site of more cover crop trials than any other private farm in the U.S. Hearing the experiences of farmers like Steve encouraged me to continue learning about cover crops, and we were able to make cover crops a priority within the Sustainable Agriculture Research and Education (SARE) program that I managed for the USDA. Over the years, SARE has funded over 1,000 projects on cover crops led by universities, nonprofits, and farmers.

Although I enjoyed working with SARE, my wife and I wanted to raise our kids closer to family in the Midwest, so we returned to Missouri after three years in D.C. Once back, I re-engaged in field work with diversified cropping systems, including a variety of alternative crops and cover crops. Some of the plants I worked with, like buckwheat, millets, canola, cowpeas, and sunn hemp, had potential both as economic crops and cover crops; other plants I worked with were used solely as cover crops, like several of the clovers and winter cereals. Over the years, I’ve had the chance to grow over 30 species of cover crops in the field. My personal favorite cover crop, crimson clover, is one I’ve grown in plots of various sizes for over 20 field seasons, and every year I try to grow and observe a variety of cover crops.

In 2010, I returned to work with SARE, focusing on the North Central (Midwest) region. I continue to work with SARE as the North Central Region Director of Extension Programs, and also direct the Center for Regenerative Agriculture at the University of Missouri. In both of these roles, cover crops and soil health have been a major emphasis area of my work.

I won’t recount all the meetings, publications, videos, and other activities I’ve been involved with on cover crops, but will simply say it’s been heartening to see the tremendous growth of interest in cover crops and the many people who have become passionate advocates for growing cover crops. While I firmly believe farmers have led the way in the current cover crop boom, there’s no question that many NRCS staff, soil and water district employees, researchers, Extension agents, crop consultants, and nonprofit educators have helped move cover crops forward. The role of the private sector has been of particular importance, including the work of many small and midsize cover crop seed companies to provide not only high-quality seed, but also high-quality information about cover crops.

While much has been written about cover crops, particularly in the realms of fact sheets, Extension bulletins, industry publications, research reports, and farm magazine articles, I felt there was a need for a book summarizing some of the latest insights from farmers and others on cover crop use and management. I hope this book will be of interest to a wide range of individuals interested in cover crops, but I have focused it primarily on farmers. I’ve tried to share information in a way that will be helpful to farmers who have not yet tried cover crops, as well as those who are using them but continuing to experiment with what works best for their farm.

Cover crop management continues to evolve, and I have no doubt that a decade from now, we’ll see continued expansion of cover crop use and further innovation in cover crop strategies. For now, I hope this book will be helpful to those of you looking for more information on the fascinating topic of cover crops and ideas on soil health management approaches that can provide many benefits to our fields, farms, and food systems.

I want to close this preface by saying this book was a family effort, with excellent contributions to editing and layout by my daughter Haley and thorough proof-reading by my wife Amy. I am indebted to them for all their time in helping to complete this book.

Rob Myers
Columbia, MO