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MDA Proposes Changes to the Phosphorus Site Index

ANNAPOLIS, MD (January 25, 2013) – The Maryland Department of Agriculture (MDA) has announced that proposed changes to the Maryland Phosphorus Site Index (PSI) were published in today’s Maryland Register. MDA will offer a 30-day public comment period on the proposed changes ending February 25.

“The Phosphorus Site Index has been updated to mirror new research that has modified this important environmental risk assessment tool for agricultural fields,” said Maryland Agriculture Secretary Buddy Hance. “Revising this tool is an appropriate follow up to our newly revised nutrient management regulations and will help us further protect the Chesapeake Bay from the damaging effects of excess nutrients.”

The Phosphorus Site Index has been replaced with the Phosphorus Management Tool (PMT). This environmental risk assessment tool is used to identify areas where excess phosphorus is present in the soil and a high potential for phosphorus loss exists. It allows users to evaluate management options that can reduce the risk of phosphorus losses from agricultural fields to nearby waterways. Revising and updating the tool is an element of Maryland’s Watershed Implementation Plan (WIP), the federally-mandated document that outlines specific steps the state will take to protect and restore the Chesapeake Bay. The PMT is included in the Maryland Nutrient Management Manual and incorporated by reference into COMAR 15.20.08.

The new PMT is the product of more than three years of peer-reviewed research conducted by scientists at the University of Maryland. Following are key changes:

  • The new tool is more sensitive to the varied environmental conditions that are found throughout the state.
  • The new tool looks separately at each pathway phosphorus travels to waterways in order to determine risks.
  • The new management tool decreases the number of categories for risk assessment from four to three.

The proposed changes to the Phosphorus Site Index as submitted to the Maryland Register, along with the Extension Bulletin to be included in the Maryland Nutrient Management Manual are available on MDA’s website or the Maryland Register.

Comments may be sent to Jo A. Mercer, Ed.D., Administrator, Nutrient Management Program, Maryland Department of Agriculture, 50 Harry S Truman Parkway, Annapolis, MD 21401. Dr. Mercer may also be contacted at 410-841-5959, or Jo.Mercer@maryland.gov. Faxes may be sent to her attention at 410-841-5950. Comments will be accepted through February 25, 2013. A public hearing has not been scheduled.
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If you have any questions, need additional information or would like to arrange an interview, please contact:

Jason Schellhardt
Director of Communications
Telephone: 410-841-5888

Megan Guilfoyle
Public Information Officer
Telephone: 410-841-5889

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