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Pollution in the Chesapeake

Phosphorous Overload on Maryland's Eastern Shore

Large-scale chicken farming in Maryland has long been one of the biggest polluters of the Chesapeake Bay. These concentrated animal feeding operations (CAFOs), as they are known, often house 100,000 chickens or more, and produce massive quantities of phosphorus-rich manure. Much of that manure ends up in the Bay, where it contributes to dead zones and other pollution-related problems.

Maryland has made a commitment to restoring the health of the Chesapeake Bay, not just for the sake of the environment but also the economy. Maryland already derives billions of dollars from the Bay, mainly from tourism, and stands to gain $4.6 billion more annually once the watershed is restored. As part of the Chesapeake Bay-wide pollution diet, a federally led plan to restore the health of the Bay by 2025, Maryland must dramatically reduce water pollutants, including phosphorus. It will not be able to do this without dealing with its excess manure problem. As it stands now, Maryland farms contribute 53 percent of the state’s total phosphorus loading to the Bay, and CAFOs make up a significant part of the problem.

Maryland law requires these CAFOs to apply for permits to pollute, and to develop and follow manure-management plans, and to report periodically on their progress. Typically, the management plans involve spreading some of the manure on fields as fertilizer for crops. But fields can only handle so much chicken manure before excess quantities of phosphorus from the manure begin washing off into nearby streams, beginning the journey to the Bay. To avoid this, many farmers ship some of their manure to other farms.Return to Map

Of the 60 concentrated animal feeding operations (CAFOs) in six Eastern Shore counties that submitted a manure-management plan between 2008 and 2014, all but one reported at least one field with excessive soil phosphorus levels. The 60 CAFOs in Dorchester, Talbot, Caroline, Wicomico, Worcester, and Somerset counties took soil samples from 1,022 fields to help plan their fertilization needs over the plan’s five-year term. Of those fields, 803—78 percent—had soil phosphorus levels in the excessive range. Excessive values tell farmers they should not apply additional phosphorus since crops are not able to absorb it and it ends up running off of fields, into streams, and eventually into the Chesapeake Bay. Yet, as an Environmental Integrity Report found, farmers reported applying three times more phosphorus in chicken manure on their fields in 2012 than their crops needed.

The required plans, known as comprehensive nutrient management plans (CNMPs), dictate how a specific CAFO is to store and transport animal waste, how and when manure may be applied to a field, and where and how often to test for water and soil quality. The CNMPs are public under federal law and portions of the plan are incorporated into the CAFO’s permit as enforceable conditions.

Failure to develop a required plan appears to be a significant problem in Maryland. CPR’s Policy Analyst Anne Havemann filed public information requests with the Maryland Department of the Environment (MDE) and received the most recent CNMPs from CAFOs operating in Dorchester, Talbot, Caroline, Wicomico, Worcester, and Somerset counties. MDE’s public database lists 488 registered CAFOs in the counties, yet the agency only had CNMPs on file for 407, meaning that 17 percent of the CAFOs in the six counties are operating without required plans.

To help farmers make decisions about manure application, the CNMPs include “fertility index values” (FIVs). This index system helps farmers determine whether adding additional phosphorus will help crops grow. Maryland interprets FIV scores in four categories: low is 0-25; medium is 26-50; optimum is 51-100; and excessive is 100 and higher. Low and medium FIVs tell farmers that crops would grow better with additional phosphorus. Optimum FIVs tell the farmer that existing soil phosphorus is sufficient for plant growth. Excessive FIVs tell farmers that there is already more than enough phosphorus in the soil to meet the needs of most crops and what crops do not use will run off.

Recently proposed phosphorus regulations would require the farms with fields with the highest FIVs (150 and higher) to limit or halt phosphorus application to those fields. The Phosphorus Management Tool (PMT) would be phased in over a six-year period; the farms with the highest phosphorus FIV values would begin implementing the PMT first but would also have the longest time to transition. Governor-elect Larry Hogan has indicated that he opposes these regulations.

To fulfill Maryland’s commitment to restoring the Chesapeake Bay, Gov.-elect Hogan should reverse his opposition in the face of overwhelming evidence of phosphorus saturation along the Eastern Shore.

How to Use the Map

The map here shows the FIV values from the fields that were tested when the CAFO prepared its CNMP. While the tests were conducted from 2008 to 2014, the results remain relevant as they were used to plan the fields’ fertilization needs over the next five years and were provided in response to CPR’s request for the most recent plan on file. The fields marked with yellow dots have P FIV values under 150 and would not be subject to the new regulations. All the other fields, marked in oranges and reds, would likely be subject to the PMT, depending upon the average P FIV value of the entire farm (the proposed regulations define how to calculate average P FIV).

The map also shows waterways (in purple) that are so polluted with phosphorus from farms that the rivers and streams are legally designated as “impaired” under the federal Clean Water Act. That designation triggered the development of the groundbreaking Bay-wide pollution diet—the starting point for finally restoring the Chesapeake Bay. Under the plan, technically known as a “total maximum daily load” (TMDL), Bay states are responsible for reducing the sources of pollution that impair local waterways. This map provides critical clues for identifying sources of pollution.

Return to map.

Read the news release on the map and Environmental Integrith Project report.

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