Special Feed for Swine May Help Farmers’ Crops, the Environment
Research shows changing pigs' food may reduce phosphorus in the soil.
Hogs at an Ohio farmResearch shows that waste from pigs that are fed a special kind of corn may help a farmer's crops. And it also may help the environment. Any farmer who raises swine knows that pigs produce a lot of waste. This has both good and bad effects. Swine waste has nutrients like nitrogen that can help fertilize crops when it is placed on the fields. But the manure contents may not be what a crop needs. And removing too much manure can be a big job.Soil scientist Brian Wienhold said most of the phosphorus in traditional corn fed to pigs is in the substance phytate. Pigs lack a chemical in their bodies to break down phytate. Most of the phosphorus in traditional corn feed passes through the animal without processing. It is expelled in the manure.Placing the usual swine manure in the fields can increase the phosphorus content of the ground. And when rains cause the phosphorus to wash away, it can harm the environment.But science may be able to solve the problem. A report on the subject recently appeared in the publication Soil Science Society of America Journal. The researchers are from the Agricultural Research Service of the United States Department of Agriculture and the University of Nebraska at Lincoln. They tested fields not far from the Nebraska cities of Lincoln and Hastings. They put three different substances on the fields: chemical fertilizer, manure from swine fed traditional corn diets and manure from swine fed low-phytate corn diets.The scientists then compared how much nitrogen and phosphorus were available in the soil. They found that using slurry from swine fed low-phytate corn diets resulted in slower build-up of phosphorus in the soil. At the same time, it did not reduce the availability of the phosphorus to the crops.Other scientists also have worked with low-phytate feed in recent years. For example, in research reported in two thousand four, University of Kentucky researchers gave pigs and chicks low-phytate feed. The substance phytase was added to the feed. The researchers said it helped break down the phytates.