Author
 |
Sharpley, Andrew |
|
Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only Publication Acceptance Date: 6/20/1999 Publication Date: N/A Citation: Sharpley, A.N. 1999. Soil inversion by plowing decreases surface soil phosphorus content[abstract]. American Society of Agronomy Meetings. p. 1. Interpretive Summary: Technical Abstract: Increased inputs of P accelerates freshwater eutrophication, which impairs water use for drinking and recreation. Continual P applications in fertilizer and manure can accumulate P in the surface 5 cm of soil and increase the potential for P loss in runoff. To investigate the feasibility of redistributing surface soil P in the profile by plowing, Mehlich-3 P rich surface soils (170 to 380 mg/kg in 0 to 5 cm) were incubated with P-deficient subsoil (2 to7 mg/kg in 20 to 30 cm) for ten manured soils. After incubating equal amounts of surface and subsoil for 28 d, Mehlich-3 P decreased 50 to 70% as a function of subsoil clay content (r of 0.84). At Klingerstown, PA, a P-stratified clay loam (370 mg/kg Mehlich-3 P in 0-5 cm) was moldboard plowed to about 30 cm. Once grass was established minimizing erosion, total P loss in surface runoff during a 30- min rainfall (6.5 cm/hr) was 2.72 mg/L compared to 16.02 mg/L prior to plowing, with dissolved P reduced from 14.80 to 2.04 mg/L. Plowing to redistribute P accumulated in surface soils has the potential to decrease P loss in surface runoff, as long as plowing-induced erosion is minimized. |
