|Mcdowell, Richard - AGRESEARCH LIMITED|
Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 15, 2005
Publication Date: July 20, 2005
Citation: Sharpley, A.N., Kleinman, P.J., Mcdowell, R.W. 2005. Response to "comments on 'Amounts, forms, and solubility of phosphorus in soils receiving manure'". Soil Science Society of America Journal. 69:1355. Technical Abstract: Continually land applying manure at rates exceeding crop removal can change soil phosphorus (P) chemistry and increase soil P to levels that are of environmental concern. To assess the effect of long-term manure application on soil P forms and solubilities, we determined water extractable P, Mehlich-3 P, Hedley P fractions, and crystalline Ca-P minerals in surface soil (0-5 cm) from 20 locations in New York (n = 6), Oklahoma (n = 8), and Pennsylvania (n = 6), which received dairy, poultry or swine manure (40 - 200 kg/ha/yr) for 10 to 25 yr. Results suggest that addition of manure to soils shifts P from Al-and Fe- to Ca-P reaction products, accounting for the relatively greater Mehlich-3 but lower water extractability of soil P. This shift has implications to environmental soil P testing. This letter is in response to comments published on our manuscript and show that the overall conclusions of our research, that the acid extractability (Mehlich-3) of soil P increased to a greater extent than water extractability in heavily manured soils, is still valid, and that these findings have important implications to environmental soil P test procedures and recommendations.