Daily Staff Writer

The Iowa State University Swine Management Research Center looks like just about every other hog farm in Iowa. But there is one big difference.

The farm is the site of research funded by the Leopold Center for Sustainable Agriculture, located at Iowa State. Research performed at the farm will be used to develop environmentally and economically sound farming practices.

The farm is situated on a self-contained watershed northwest of Ames and it is being used to develop a swine and cropping system that is profitable with a minimal environmental impact.

“Because of the importance of the pork industry in Iowa, the university has committed significant resources to studying new technologies that can be used by our pork producers on their own farms,” said ISU President Martin Jischke.

“We want to help producers expand their operations and protect the environment at the same time. The key is responsible growth. In the pork industry, responsible growth means sustainability and hog production is an excellent example of sustainable agriculture.”

The research on the farm is being conducted by the animal waste management issue team, led by Stewart Melvin, head of agricultural and biosystems engineering. The team has been conducting research in a variety of areas.

“This research provides Iowa State with a little more information in terms of how we manage agriculture,” said agronomy professor Randy Killorn, one of the principal investigators on the project. “We have generated evidence that we could use to make recommendations with some degree of confidence that this is a good way to do it.”

Natural Recycling

Sustainable agriculture systems should maintain a balance of nutrient input and output. Inputs are things like feed, energy, fertilizer, seed, pesticides and labor. Outputs are things like animals, grain, runoff and pollutants. The ideal system is one that maximizes animal and grain output while minimizing loss of nutrients in the form of runoff and pollutants.

The research farm uses the latest technology to determine what happens to nutrients applied to crops as liquid manure. A special record-keeping system is used to track all cropping, fertilizer and pesticide use. Ground and surface water quality is monitored, as is the air for odor.

“We are, in a broad sense looking at nutrient flows on and off this farm,” Killorn said.

Melvin has been looking at nutrients coming onto the farm primarily as feed, and analyzing the waste produced by pigs, in an attempt to achieve a nutrient balance on the farm.

Current studies have shown that there have been no significant changes in surface and ground water nitrate when liquid manure is used as a fertilizer. By injecting the manure into the soil, odor is reduced.

Previous research has shown that although adding hogs to a crop farm increases the amount of labor, it generates enough income to increase the return per hour of labor. In fact, adding hogs to a crop farming operation increases return regardless of the productivity of the land.

Manure and soybeans

At the research farm, scientists will look at the optimum rates for hog manure fertilizer application on corn and soybeans.

Killorn has conducted research showing that hog manure can be used as an effective fertilizer on corn and soybean crops that are in rotation. Hog manure can increase soybean yields if it is applied to the field in the spring following a corn crop.

Most crops in Iowa are rotated Killorn said, and this method could nearly double the number if Iowa acres available for land application of manure.

The new approach has shown good results, and as an added advantage, it helps maintain crop residues on the fields that cuts down on erosion, Killorn said.

“By applying manure following corn, there is a much better chance of maintaining what’s left behind on the soil,” he said. “We know that leaving [crop residue] on the soil can go a long way to preventing soil erosion.”

In addition, the rates at which manure needs to be applied to be effective is normal and does not seem to have any adverse effects on the environment.

Killorn said manure can be effectively injected into the soil to reduce odor.