Farmers are always looking for new ways to improve yields and save money on input costs. Since 2001, researchers at Iowa State University have been running a cropping system experiment looking to reduce costs on fossil fuels and make soil healthier in the long term, says Matt Liebman, professor of agronomy at Iowa State University. The research used a new variation on crop rotation that produced high corn yields, comparable to current yield standards.
Within the study, a four-year or five-year rotation of corn, soybeans, oats and alfalfa was tested over the typical two-year rotation of corn and soybeans. In their research, Liebman says, the larger-rotation setup provided a 56% reduction in fossil energy use over a six-year time.
In the rotation, the researchers plant corn first followed by soybeans, and they plant the oats and alfalfa together. The oats are harvested, and the alfalfa is left in the field to make hay in the spring, Liebman says.
For a commercial farmer, a five-year rotation would have greater energy savings. For the conditions that were observed during their experiment including grain prices, input costs and labor costs, they found the experiment to be a break-even deal. The profit was $250 an acre on average without the charge for land.
The four-crop rotation does take more management skills and a desire to use a joint-farming operation, but when energy prices go up, it might be a more attractive option for farmers.
Their experiment also suggests that crop farmers who pair with livestock farmers, buy livestock or have a good market for grain and hay in their area for the rotation will be the most profitable. Livestock can provide the little manure needed to keep phosphorus and potassium in the soil. Nitrogen can be obtained from nitrogen fixation in the alfalfa crop, Liebman says.
There are more advantages to the rotation than simply reducing fossil fuel costs. The soil is much healthier and better off in the longer rotation, Liebman says. There is better soil structure and water is held and absorbed more efficiently.
Additionally, Liebman says it's a good idea to anticipate energy prices going up in the future and have a plan in place to reduce those costs.
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