Hog manure hasn’t changed much over the years, but attitudes toward its value and role in agricultural production has changed. Jerry Hatfield, laboratory director of USDA’s Agricultural Research Service National Soil Tilth Laboratory in Ames, Iowa, in a new report outlines manure’s benefits as an agronomic input. The major points include:
1. Manure provides positive short- and long-term benefits to the soil. These changes are derived from physical, chemical and biological responses to manure.
Organic materials contained within manure increase the availability of nitrate — nitrogen and phosphorus; increase the cation exchange capacity; increase soil organic matter; decrease the carbon/nitrogen ratio. These materials also increase infiltration rate and soil water-holding capacity through changes in soil organic matter. The absolute degree of change varies among soils, but these trends are evident in nearly all studies presented.
2. Manure is an economical substitute for commercial fertilizers.
3. Pork producers could increase profits if they use manure as a resource to supply nutrients for crop production, especially corn.
4. Studies suggest there is a large untapped potential for the profitable use of manure nutrients in crop production across the United States.
5. Manure may restore eroded soils to higher levels of productivity. A 1993 study shows that the value of manure as a soil-restoration material for eroded soils was greater than its application on non-eroded soil.
6. Despite the reduced availability of manure nitrogen, crop yield increases normally occur with manure application.
7. Manure is a valuable and under appreciated soil resource.
8. There is ample documentation that shows manure can increase the quality of the soil, enhance and stabilize crop production and be managed without imposing an environmental risk.