Crop rotation means changing the crop planted in a field from year-to-year. In the U.S. Midwest, it is common for grain growers to practice a two-year crop rotation by alternating between corn and soybeans in a given field each year.
In order to gain maximum benefits from crop rotation, you need a rotation sequence that is longer than two years. Multi-year rotations break up weed cycles as well as insect life cycles and certain disease cycles, reducing the damage these cause to crops. Including legumes in the rotation can create the conditions that lead to improved soil structure and fertility, which over the long term leads to increased crop yields with fewer purchased inputs. Growing a more diverse array of crops spreads out financial risk because a single crop failure will not be so disastrous (1). These benefits are seen by organic farmers who are required to use multi-year crop rotations, but the same benefits also happen on non-organic farms that use long crop rotations.
In spite of the fact that longer rotations can have net returns per acre as high or even higher than two-year rotations, the vast majority of agricultural acres in the Midwest are in a two-year rotation. Part of the reason is that in two-year rotations, fossil fuel inputs substitute for the higher labor inputs required for the three- and four-year rotations (2; see 2-year, 3-year, and 4-year Rotations text box). Lots of farmers choose the two-year rotation and accept the relatively small reduction in net return per acre in order to operate many more acres with less labor.
How can a landowner make it possible for the future land owners or operators to use a three- or four-year crop rotation? Beyond the higher labor requirement, there are costs in the form of background management and machinery ownership to deal with a complex multi-crop system (see Complexity Costs text box). Retiring farmers or landowners could consider giving the future farm operator a credit for all or part of the higher management costs he or she will incur from using a long rotation.
The choice to include a longer rotation partly comes down to the determination of the landowner and farm operator. Long rotations that reduce fertilizer and pesticide expenses are an easier decision to make in years when grain prices are low. It takes a stronger commitment to stick to it in years when grain prices are high, when it’s really tempting to let go of the long rotation in favor of a large profit from planting all acres to corn (see Corn & Soybean Profitability text box).
If the future operator will not own the land, you should consider a long-term lease arrangement to ensure that the farm operator can maintain a three- to four-year crop rotation system. You can specify multi-year rotations in the terms of a lease. Use land rental rates that are in line with typical rates in your area, that reflect the crop production potential of your soil, and that give the farmer sufficient profit potential so that she or he will be able to stick to the longer rotation in good years and bad years. Your local NRCS office can help you find those appropriate rates. If the future operator will also be the owner, you can use deed restrictions or covenants to ensure that the land will be treated the way you want. See Conservation Financing for more details about these tools for farm transitions.
Use the Crop Rotations Cost/Benefit Table to estimate the value of longer crop rotations for your farm.
(1) Rotation. In Organic Risk Management: Tools for Managing Pest and Environmental Risks to Organic Crops in the Upper Midwest. 2010. Editors: Kristine M. Moncada and Craig C. Sheaffer.
www.organicriskmanagement.umn.edu (accessed 8/27/13)
(2) Energy and Economic Returns by Crop Rotation. September 2012. Ann M. Johanns, Craig Chase, and Matt Liebmann. Iowa State University Extension. www.extension.iastate.edu/agdm/crops/html/a1-90.html (accessed 8/12/13).
Ag Decision Maker, Whole Farm Decision Tools. Iowa State University Extension and Outreach. www.extension.iastate.edu/agdm/decisionaids.html
This online toolbox, created by Iowa State Extension, helps farmers answer hundreds of “what if” questions about their operations and about possible new enterprises. Worksheets are available to evaluate production decisions, marketing decisions, machinery questions, etc.