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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #103209
Title: RELATING SOIL PHOSPHORUS RELEASE TO THE POTENTIAL FOR PHOSPHORUS MOVEMENT IN SURFACE AND SUBSURFACE RUNOFF

Author
item MCDOWELL, R - CAMBRIDGE UNIVERSITY
item Sharpley, Andrew

Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 5/20/1999
Publication Date: N/A
Citation: Mcdowell, R.W., Sharpley, A.N. 1999. Relating soil phosphorus release to the potential for phosphorus movement in surface and subsurface runoff[abstract]. American Society of Agronomy Meetings. p. 1.

Interpretive Summary:

Technical Abstract: The accumulation of P in intensive farming systems has resulted in more P being land applied than crops require, an accumulation in soil P, and increased potential for P loss in surface runoff. To develop P-based management plans, we need to be able to estimate the release of P from soil to runoff water. Soil samples (0-5 cm depth) were collected from a mixed land-use watershed in Pennsylvania covering a wide range in Mehlich-3 P (10-650 mg/kg) for four silt loams. Both water and CaCl2 extractable soil P were closely related to Mehlich-3 P. Above a Mehlich-3 P of 175 mg/kg, however, there was a more rapid increase in release of P to water and CaCl2, suggesting a threshold value exists, above which the potential for soil P release is greater. Using simulated rainfall (5 cm/hr for 30 min), the concentration of dissolved P in surface runoff and leachate from undisturbed columns of these soils, increased more rapidly above the Mehlich-3 P threshold of 175 mg/kg. The use of water extractable soil P t estimate surface runoff P and CaCl2-P for leachate P is proposed.