[gardeners] Fwd: Composting Research Improves a Time-Tested Technique

Margaret Lauterbach (gardeners@globalgarden.com)
Wed, 06 Aug 2003 10:34:47 -0600

>ARS News Service
>Agricultural Research Service, USDA
>Sharon Durham, (301) 504-1611, sdurham@ars.usda.gov
>August 6, 2003
>Composting continues to have a place in farm animal operations, according
>to Agricultural Research Service scientists who are finding ways to make
>composting even more feasible for animal producers.
>In field experiments by microbiologist Patricia Millner at the ARS
>Environmental Microbial Safety Laboratory in Beltsville, Md., 99.99
>percent of the pathogens Escherichia coli and Salmonella were eliminated
>from manure after composting. But the scientists stressed that composting
>for the right amount of time, and at the proper temperature, is the key to
>controlling pathogens in compost.
>Composting is one of several methods farmers can use to treat animal
>manure, sewage sludge and other organic residuals that contain pathogens
>or parasites of public health concern. The temperature of an aerated
>compost pile--one that's turned frequently to allow air to penetrate--must
>be at least 131 degrees Fahrenheit for three consecutive days to reduce
>pathogens to safe levels. For unaerated compost piles--those that are
>turned only five times--the temperature must reach 131 degrees Fahrenheit
>for two weeks.
>In many states, untreated manure can be applied to farm fields. However,
>this can introduce pathogens and parasites into soils, and even into
>runoff or irrigation water. As organic vegetables and fruits gain
>popularity, the demand for animal manure is expected to increase.
>Millner is conducting research on what she calls hybrid composting
>systems. Not only do these systems reduce numbers of pathogens like E.
>coli and Salmonella, they also reduce excess available phosphorus and keep
>the ratio of nitrogen to phosphorus within a range acceptable for use in
>areas that have nutrient-management plans. This approach means that
>composting can address nutrient, pathogen and odor concerns all at the
>same time.
>More information about this research is in the August issue of
>Agricultural Research magazine, available on the World Wide Web at:
>ARS is the U.S. Department of Agriculture's chief scientific research
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