How Farmers Can Boost Yields and Cut Costs with Smarter Crop Rotations

When choosing the crops you grow, consider rotational impacts. These could affect yields as well as inputs, helping or hurting your bottom line.

“Farmers tend to do what they’ve done in the past, particularly in the Midwest, causing rotations to become fixed,” said Gary Schnitkey, Extension agricultural economist at the University of Illinois. “But we need to think about rotational impacts of crops. For instance, yields of corn after soybeans will be better than yields of corn after corn. There is also likely to be more disease and more need for [nitrogen] in a corn-corn rotation than in a corn-soybean rotation.”

Corn yields also increase, he said, when a cereal grain, perhaps wheat, is added to a corn-soybean rotation. And adding other alternative crops can lower inputs such as pesticides and fertilizer. “The challenge is finding a crop to add to the rotation that has a high enough value to compete with the value of corn and soybeans,” he said. 

Simple as ABC

A tool that may help analyze the financial pros and cons of existing or hypothetical rotations is the Agricultural Budget Calculator (ABC). Developed by the Center for Agricultural Profitability in the University of Nebraska-Lincoln’s department of agricultural economics, the ABC is a free online program designed to help farmers and ranchers figure cost of production and project economic returns for various enterprises. It can analyze profitability of individual crops on dryland and irrigated acres.

“You can do an analysis of your base crops of corn and soybeans, for instance, and then use a crop comparison break-even analysis built into the program that lets you compare alternative crops with the base crops,” said Glennis McClure, Extension educator and farm and ranch management analyst at the University of Nebraska-Lincoln. McClure helped develop the ABC.

“The program takes a look at all material inputs to crops and then provides a net return over operating costs,” she said. Based on your tillage practices or harvesting needs, the program computes machinery costs for each crop, including fuel, repairs, depreciation, and opportunity costs of ownership.

The program also lets you analyze field-by-field crop profitability.

“You can also use the program to project profitability of crops for several years on an enterprise-by-enterprise basis and compare that with a projection of how those crops impact the profitability of the whole farm,” she said. “Looking at whole-farm profitability lets you see what various crop rotations provide in potential net return. For instance, you might see that a particular crop rotation helps reduce fertilizer costs. It’s a great planning tool.”

Analyzing an actual rotation’s year-by-year whole-farm profitability lets you see how yields and inputs change over time. “You can see whether or not you’ve been able to reduce pesticides for weeds and diseases,” McClure said. “You can measure and project economic impacts over the long term.”

Long-Term View

Short-term changes in economic benefits resulting from switching or adding crops are evident because of immediate data relating to crop price and cost of inputs. But rotational impacts resulting from synergies between crops, and how those impact soil health, weed suppression, and plant disease are more difficult to project. Because the potential benefits of changing the rotation often hinge on a farm’s soil type and weather, it’s hard to pinpoint projected yield increases and savings on inputs.

To get relevant baseline crop performance data, McClure advised setting up on-farm research plots that help you evaluate the potential benefits of changing your rotation. “You can see how yields are affected,” she said.

“On the cost side of things, you can see whether or not there are fertility changes,” she added. “For instance, if you’ve been growing continuous corn, you can analyze what happens to the fertilizer inputs required if you add to the rotation crops like soybeans or alfalfa, both of which will add nitrogen to the soil. 

“You can see, too, how rotational change may impact the need for pesticides. You might find that the rotational change results in a reduced need for pesticides to control weeds and insects.”

Rotational benefits of switching or adding crops can emerge fairly quickly, said Katja Koehler-Cole, soil health management Extension educator at the University of Nebraska-Lincoln. “In just one season, a cover crop planted after corn can take up excess nutrients in the soil, preventing them from leaching into the groundwater,” she noted.

But she added: “Changes in microbial populations and other aspects of soil health, such as improvements to soil organic matter, can take a few years. To account for those, you have to take a long-term view of profitability.”

In the long term, improving soil health by diversifying crop rotation often boosts yields. It may also cut costs by decreasing the need for fertilizers and pesticides.

“By adding more diverse plants, such as a cover crop or a crop other than corn or soybeans, you’re feeding more of the soil microbes,” Koehler-Cole said. “Some crops particularly support mycorrhizal fungi, which can aid crops in accessing water and nutrients, increasing cropping system resilience.

“Adding legumes to the rotation adds nitrogen,” she said. “Adding cover crops adds organic carbon. It all helps with nutrient efficiency.” The sum effect can increase residue decomposition, which cycles nutrients back to the soil faster.

Think Holistically 

Adopting a rotation that includes winter and summer annuals can help suppress weeds, resulting in input savings, Koehler-Cole noted. Adding winter wheat, for instance, to a corn-
soybean rotation provides ground cover and scavenges excess nutrients, improving nutrient efficiency and resulting in the need to apply less nitrogen.

As plant diversity increases microbial populations and soil carbon, soil aggregate stability improves and soil organic matter increases. “This improves water infiltration and water retention in the soil,” Koehler-Cole said.

Crop yield stability may result from the cumulative soil-health benefits of growing diverse crops. “Crops are better able to withstand severe weather, and the crop diversity spreads risk as well,” she said.

When choosing crops to add to the rotation, Koehler-Cole said: “Educating yourself about alternative crops is an important first step. Be sure to select crops that are adapted to your region. For instance, small grains, like winter wheat, spring oats, triticale, and cereal rye, are widely adaptable. But of course, you must have a market or use for those crops. Take a holistic view of your farm as you diversify your rotation.”