Five-Year Summary of Mehlich-3 P Data From Home Lawn Soil Tests In Pennsylvania.

Use of phosphorus containing fertilizers for home lawns is receiving intense scrutiny from state and federal regulatory agencies.  Legislation restricting P and N fertilizer on home lawns was recently introduced in Pennsylvania, and implications of the proposed bill are currently being discussed with stakeholders.  To provide background information for regulators and industry stakeholders, we summarized soil test P data from 34,456 home lawn soil samples submitted to Penn State’s Agricultural Analytical Services Laboratory (AASL) from 2004 to 2009.  Results showed that 40% (13,824) of the samples submitted by homeowners to AASL were less than or equal to 45 mg kg^-1 Mehlich-3 P.  Home lawn samples having less than 45 mg kg^-1 Mehlich-3 P receive a P fertilizer recommendation from AASL.  Of the remaining samples, 53% (18,199) were between 46 and 200 mg kg^-1, and 7% (2,433) were above 200 mg kg^-1 Mehlich-3 P.  200 mg kg^-1 Mehlich-3 P is considered the threshold above which the P Index should be used to estimate the risk of P loss from agricultural soils in Pennsylvania.  Mean, median, and mode of Mehlich-3 P concentrations for all 34,456 home lawn soil samples were 81.8, 57.0, and 28.0 mg kg^-1, respectively.