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item Sikora, Lawrence
item Adler, Paul

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/2000
Publication Date: 11/5/2000
Citation: Sikora, L.J., Adler, P.R. 2000. Phosphorus availability changes with poultry compost age. 2000 ASA, CSSA, SSSA Annual Meeting, November 5-9, 2000, Minneapolis, MN.

Interpretive Summary: .

Technical Abstract: Manure application may alter the availability of the soil nutrients by stimulating biological activity and mineralization. Composting stabilizes manures so that biological activity of the compost is less than the manure. To test if the compost process alters the availability of P, a field-laboratory study was conducted which followed the water- and Mehlich 1-P extractable levels in soils amended with poultry manure composts of different age or maturities. Composting was performed over 8 weeks using poultry manure- woodchips-straw mixture and the windrow composting method. Samples were taken at 0, 2, 4, and 8 weeks and tested for stability using the self-heating test. Samples were added to two soils, a clay and a silt, containing high and low extractable levels of P and incubated at room temperature for 8 weeks. Data indicated that extractable P levels of amended soils increased form 0 to 2 weeks of composting and declined thereafter to 8 weeks. Soil type did not affect these results. These results indicated that composting causes the release of inorganic P from organic forms resulting in the peak at two weeks. Amending soils with immature or insufficiently stabilized composts may result in potentially higher P concentrations in runoff.