Problem: Declining Quality of
the Bay
Image courtesy of the Chesapeake
Bay Program. |
The Chesapeake Bay,
with an area approximately 2,300 square miles, is the largest estuary
in the contiguous United States. It receives about half of its water
volume from the Atlantic Ocean and half from its 64,000 square mile watershed,
which includes six states and
the District of Columbia. |
The Bay is very shallow,
averaging approximately 6.5 meters in depth. Compared to other coastal and
inland bodies of water, the Bay has a large drainage basin for the volume
of water it contains. This large watershed-area to water-volume ratio, coupled
with increased spring and summer halocline formation, makes the Bay particularly
vulnerable to the effects of nutrient pollution.
Concerns regarding declining
water quality in the Bay and its tributaries led to a six year study of water
quality in the Bay in 1976. About 40 research projects, coordinated by the
U.S. Environmental Protection Agency (EPA), documented declining water quality
and reduction in the numbers and diversity of fish, shellfish, and submerged
aquatic vegetation (SAV).
Eutrophication and
turbidity caused by soil sediments and an increase in plant nutrient inputs
were considered to be the main causes of these changes.
Nutrient reduction was therefore
considered to be the major factor in improving habitat for benthic organisms
and fish by reducing algal blooms and increasing light penetration to SAV.
'Water Quality' models, simulating ecosystem processes, were used to establish
40 percent reduction goals (from a 1985 base) for nutrients entering the
Bay.
Moving Towards Solutions
In 1987 the Chesapeake
Bay Agreement was signed by Maryland, Virginia, Pennsylvania, the District of
Columbia, the EPA, and the Chesapeake Bay Commission adopting this reduction
goal to be attained by the year 2000. Refinement of the water quality model
led, in 1992, to the adoption of Tributary
Strategies, which allocated nutrient
reductions to the Bay's major watersheds. Within Maryland's watersheds, nutrient
loads were determined on the basis of point source loads and land use loading
rates and areas.
Each of the state's ten
major watersheds then developed a Tributary Strategy targeted at meeting
Maryland's 40 percent reduction goal. Program and practice options for nutrient
reduction within the watershed were evaluated and the most promising options
identified.
Tributary plans provide
the opportunity to integrate nutrient reduction efforts through a wide variety
of initiatives and a framework for a comprehensive approach to nutrient reduction.
One option identified as being able to play a major role in the reduction
of nutrients from agricultural non-point sources is nutrient management planning.
Agricultural Nutrient Management
in Maryland
Prior to the Chesapeake
Bay Agreement, programs already existed to implement some aspects of water
quality improvement, but no program was in place to specifically address
nutrient management planning. In 1989 the Maryland Department of Agriculture
and the University of Maryland/Maryland Cooperative Extension established
the Maryland Nutrient Management Program (MNMP). The primary focus of this
program was to place 1.4 million acres of Maryland farmland under nutrient
management plans by the year 2000.
In 1998 the Maryland legislature
enacted the Water Quality Improvement Act (WQIA) which mandated sweeping
changes for Maryland's agricultural community and land managers. The WQIA
requires:
-
nitrogen and phosphorus-based nutrient management
plans;
- reduction of the phosphorus in manure
via feeding regimes;
- provisions for transporting animal
manure from fields showing excessive phosphorus to fields needing additional
nutrients;
- increased scrutiny of record keeping;
and
- additional evaluations of the phosphorus
nutrient.
Nutrient management planning is a series
of best management practices (BMPs) aimed at reducing nutrient pollution
by balancing nutrient inputs with crop nutrient requirements. Nutrient management
planning is considered one of the most effective means of controlling excessive
nutrient applications.
To facilitate nutrient management planning,
Extension has placed advisors based in county offices thoroughout the state.
Extension advisors provide nutrient management planning services to clients
following a priority which emphasizes:
- Farmers with pollution problems or
referred as non-compliant by MDA through an enforcement procedure.
- Farmers participating in the Manure
Transport Project and those with a MACS application pending for animal
waste storage or poultry mortality composters.
- Updating nutrient management plans
for existing clientele with expired plans developed by MCE Nutrient Management
Advisors.
- First come, first serve for any other
farmer who must comply with the Water Quality Improvement Act.
Nutrient management plans are documents
which incorporate soil test results, yield goals, and estimates of residual
nitrogen to generate field-by-field nutrient recommendations. By 2001, the
Extension program and private consultants had placed approximately 1.26 million
acres under nutrient management plans. A particularly successful element
of this program is the increased use of a pre-sidedress nitrate test (PSNT)
for corn by producers. Since 1992, legislation has required
the certification of nutrient management consultants and has enabled licensed
private sector nutrient management consultants to play a major role alongside
those in the public sector. Certification, examination, and licensing are
administered by MDA in consultation with a Nutrient Management Advisory Committee.
Continuing education courses are also conducted. The MNMP plays a major role
in implementing this expanding education and training program. Licensed consultants
and firms are required to report their planning progress to the MNMP annually.
The geographic area under nutrient management planning is monitored on a
watershed basis, enabling progress with Tributary Strategies to be assessed.
Questions and/or
comments should be sent to jsalak@umd.edu
University of Maryland | College Park MD, 20742
Page last modified August 1, 2007 | © 2005 University of Maryland
|
