Ninety percent of grain growers use crop rotations (most of those are two-year rotations), but fewer than 7% use cover crops in their rotations and only about 1% of all cropland acres were in cover crops in 2010 (1). Most cover crops planted by Midwestern farmers are not harvested and sold. Rather, they are planted and then chopped, mowed, or plowed down.
Cover crops help build soil organic matter by scavenging nitrogen and other nutrients left in the soil and using it for growth, tying it up in the plant material of the growing cover crop. Once the cover crop is chopped, mowed, plowed, etc., the billions of bacteria and fungi that live in the soil break down that plant material gradually. Cover cropping has multiple benefits on the farm and off the farm, many of which are difficult to represent in dollars. Cover crops keep living roots in the ground when there is no cash crop growing, which keeps soil anchored in place and reduces soil erosion. This in turn contributes to improved water quality. Cover crops help to break weed, pest and disease cycles, which results in lower crop damage and avoided costs from lower use of herbicides and pesticides. Cover crops, especially legumes, can contribute nitrogen to the next cash crop, reducing the need for purchased fertilizer (2,3; see Cover Crop Nitrogen text box). Each one of these effects may be fairly subtle and might not be seen every year; depending on weather conditions, the cover crop used, and how the cover crop is managed. Overall, especially over time, the impact of consistent cover cropping on the whole farm’s system can be very positive (3; see Cover Crop Yield Gain text box).
An interesting feature of cover crops is that they are frequently aerial-seeded into a standing crop. “Flying” the seed onto the field with a small plane avoids any damage to the cash crop caused by running seeding equipment on the ground. Cover crop seeding is often done in the middle of the growing season, once the crops are already beginning to mature. As the cash crop matures, it drops leaves or leaves dry up, letting more light through the crop canopy to allow the cover crop to grow (4). The cover crop is then established at the time of cash crop harvest and may continue to grow after harvest, depending on weather conditions. Besides use with corn and soybeans, cover crops can also be effectively used with many other cash crops such as wheat, other small grains, sunflowers or other oilseeds, or vegetable crops.
If cover cropping is a practice that you want to encourage in your farm transition plan, then it is important to recognize the long-term investment nature of cover cropping in the way that you structure a rental, lease, or sale agreement. There are costs to planting and then plowing down a cover crop, and a time cost of managing a complex system. There are multiple benefits to cover cropping, but they build up over time and it may take several years to see the benefits.
Some things to consider:
- Converting all or part of a farm operation to cover cropping is a situation in which it might make sense to use a “stepped rent” together with a long-term lease, with payments lower in the first few years than in subsequent years. If the land will be sold, structuring the payments to be lower in the first few years would help encourage cover cropping.
- As the long-term benefits of cover cropping become more clear, conservation programs (public and private) are stepping in to offer incentive payments for cover cropping. Program payments can be part of the financing for a farm that uses cover cropping.
- Landowners might consider giving the farm operator a credit for the extra management work that leads to long-term improvement of the soil.
- Retiring farmers and landowners who want to see cover cropping happen on their land will also need to clearly specify this requirement in the terms of any agreement because it isn’t the easiest choice for a farmer to make when it comes to labor and management costs. See Conservation Financing for more information about options for rent or lease terms.
Use the Cover Cropping Cost/Benefit Table to estimate the value of cover crops on your farm.
(1) While Crop Rotations are Common, Cover Crops Remain Rare: USDA/ERS
(2) Winter Cover Crops. 2010. Kristine Moncada and Craig Sheaffer. In Organic Risk Management. Eds. Kristine Moncada and Craig Sheaffer. University of Minnesota.
www.organicriskmanagement.umn.edu/winter_cover13.html (accessed 9/03/13).
(3) Managing Cover Crops Profitably. 2007. Sustainable Agriculture Research and Education (SARE), USDA.
www.northcentralsare.org/Educational-Resources/Books/Managing-Cover-Crops-Profitably-3rd-Edition (accessed 9/03/13).
(4) Aerial Seeding Cover Crops. 2012. Allamakee Soil & Water Conservation District.
(5) 2012-2013 Cover Crop Survey. June 2013. Steve Werblow and Chad Watts. Conservation Technology Information Center (CTIC) and North Central Region SARE.
www.ctic.org/media/pdf/Cover%20Crops/SARE-CTIC%20Cover%20Crop%20Survey%202013.pdf (accessed 8/9/13)
(6) 2013 Iowa Farm Custom Rate Survey. March 2013. William Edwards, Ann Johanns, and Andy Chamra. In Ag Decision Maker, Iowa State University Extension and Outreach.
Cover Crop Chart: An intuitive educational resource for extension professionals. 2013. Liebig, M.A., H.A. Johnson, D.W. Archer, J.R. Hendrickson, K.A. Nichols, M.R. Schmer, and D.L. Tanaka. Journal of Extension [Online], 51(3) Article 3TOT7. Available at www.joe.org/joe/2013june/tt7.php. (accessed 9/03/13).
Visually similar to the periodic table, the CCC includes information on 46 cover crop species and provides information regarding the suitability of these crops for addressing different production and natural resource goals.
Cover Crop Decision Tools. Midwest Cover Crops Council.
www.mccc.msu.edu/selectorINTRO.html (accessed 9/03/13).
This online resource has cover crop information specific to seven states and the province of Ontario, and allows you to enter your farm’s information to build a plan specific to your farm.
Using Cover Crops to Improve Soil and Water Quality. 2009. James Hoorman. The Ohio State University Extension. http://mercer.osu.edu/topics/agriculture-and-natural-resources/Using%20Cover%20crops%20SAG%2008%2009.pdf (accessed 9/03/13).
The four-page publication summarizes of all the ways cover crops help farmers improve their soil and water quality with cover crops. It presents advantages and disadvantages of cover crops and lists the different effects of cover cropping on soil and water quality.
Winter Cover Crops. 2010. Kristine Moncada and Craig Sheaffer. In Organic Risk Management. Eds. Kristine Moncada and Craig Sheaffer. University of Minnesota.
www.organicriskmanagement.umn.edu/winter_cover13.html (accessed 9/03/13).
This online manual is intended as a guide for organic and transitioning producers in the Upper Midwest, but includes a lot of good basic agronomic and soil science information that is useful to non-organic farmers as well.
Soil Health. Burleigh County, North Dakota Soil and Water Conservation District.
www.bcscd.com/?id=23 (accessed 6/11/13)
This county-based program offers a number of useful resources on soil management and cover crops.
Special Report on Burleigh County’s Soil Health Team.
The Land Stewardship Project has developed a series of articles on what farmers, conservationists and scientists are doing in one North Dakota Soil Conservation District to build healthy soils using cover crop cocktails and other methods.