ABSTRACT:
Expansion of production in north central Iowa has occurred in dense clusters of confined feeding operations (UFOs), which poses questions about how manure nutrients are distributed on the landscape and whether manure management regulations are sufficient to protect water quality. Public record were used to document the manure management practices of 10 GZFOs housing 59,700 finishing hogs in a 1,554 ha area of Hamilton Coung, Iowa. Together, the UFOs generated an estimated 811,500 kg of nitrogen (N) each year, more than 70% of which volatilized into the atmosphere. CAFOs minimized the area required for applying manure by underestimating manure N content, projecting above average crop yields, and applying manure to soybeans. Some fields were claimed by more than one WO, and some field sizes were overestimated. Manure application based on crop demand for phosphorus would require 9,350 ha of cropland, compared to the 990 ha used by UFOs. Several policy changes could alleviate the nutrient management problems inherent in UFOs.
Footnotes
Laura L. Jackson is Associate Professor with the Department of Biology at the University of Northern Iowa. Dennis R. Keeney is Emeritus Professor retired from the Leopold Center for Sustainable Agriculture, Iowa State University. Elizabeth M. Gilbert holdr a doctorate in Sociology and Lives in Hardin County, Iowa.
- Copyright 2000 by the Soil and Water Conservation Society
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