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Universities Council on Water Resources
Journal of Contemporary Water Research & Education
Issue 151, Pages 3-8, August 2013
Nutrient Management and the Chesapeake Bay
Douglas Beegle
Penn State University, University Park, PA
Abstract: The Chesapeake Bay is the largest estuary in the United States with a very large and diverse
watershed. The health of the Bay related to pollution from nutrients and sediment has been in decline
for many years. Agriculture in the watershed is one of the major contributors of nutrient and sediment
pollution to the Chesapeake. The cause of the nutrient pollution from agriculture has usually been thought
to have been the result of mismanagement of nutrients on farms. Consequently, the approaches to solving
the problem have focused almost exclusively on changing farm management. As a result, significant
progress has been made in improving on-farm nutrient management but the health of the Bay remains a
concern. An analysis of the structure of animal agriculture in the Bay watershed reveals that the problem
is much deeper than simply mismanagement on farms. A major underlying cause is a regional nutrient
imbalance resulting from an economically driven system of animal production based on importing from
outside the watershed a large amount of the animal feed. Therefore, a long-term, sustainable solution
will require much more than just changing on-farm management. To really solve this problem will require
a restructuring of the animal production systems to internalize the environmental costs of this structural
imbalance of nutrients in the watershed. The challenge that must be met is how to accomplish this in a
way that is sustainable.
Keywords: Chesapeake Bay, nutrient management, agriculture
T
he Chesapeake Bay is the largest estuary
in the United States with a watershed
that covers 64,000 square miles across
six states. Over 17 million people currently live
in the watershed and experts predict that the
population will increase to nearly 20 million by
2030. The Bay watershed has a wide variety of
land uses, including intensive urbanized areas and
extensive suburban areas (9 percent), a large area
of agricultural land (22 percent), and extensive
forests (58 percent) (Chesapeake Bay Program
2012). As population has grown and undeveloped
land has been converted to other land uses, there
has been a decline in the health of the Bay. This
first became a serious concern in the 1970’s.
The causes of the decline are many and varied,
ranging from industrial chemicals, air pollution,
over harvesting of seafood, soil erosion and
sedimentation, and nutrient pollution. Nutrients
are coming from all land uses in the watershed and
both from point sources, such as sewage treatment
plants, and non-point sources, such as agricultural
Journal of Contemporary Water Research & Education
fields. The nutrients of concern are nitrogen (N)
and phosphorus (P), both of which are essential
for plants and animals. In fact, the main problem
caused by nutrient pollution is too much of a
good thing. This can result in excessive growth
of algae, or accelerated eutrophication, which
blocks sunlight thus reducing underwater grasses
that are vital to the health of the Bay. Also, when
these algae blooms die and decompose, they can
dramatically lower dissolved oxygen in the water,
making large areas of the Bay uninhabitable.
In response to this decline in Bay health, the
Chesapeake Bay Program was established in the
1980’s to restore the health of the Bay. While
all of the major land uses contribute significant
nutrient loads to the Bay, analysis of the nutrient
and sediment contributions shows that agriculture
is the main source of nitrogen (45 percent) and
phosphorus (44 percent) in the total delivered
load of these nutrients (ChesapeakeStat 2009).
Consequently, a major effort has been undertaken
to address this problem across the watershed.
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Beegle
Underlying Causes of Nutrient
Problems from Agriculture in the
Chesapeake Bay
It is important to understand the causes of nutrient
pollution in the Bay from agriculture. There are
two main issues that lie behind this problem. One
is a strategic issue that has to do with the structure
of contemporary animal agriculture. The second
has to do with tactical management of nutrients on
individual farms.
Traditional animal agriculture has been organized
around localized nutrient cycles (Figure 1A) because
of the integration of the crop and animal production
systems on individual farms. In most cases, the bulk
of the feed required for the animals was produced
on the farm where the animals were located.
Animal utilization of feed nutrients is relatively
low, with approximately one-fourth to one-third
of the nutrients going into the animal products
and two-thirds to three-fourths into the manure. In
this integrated system the manure nutrients were
returned to the land where the crops were produced.
Some external sources of nutrients were required
for the crops to offset the nutrients that left the
farm in the animal products. In this system there
was a very strong incentive to recycle the manure
nutrients as efficiently as possible into the cropping
system. The more nutrients that could be recovered
from the manure for crop production, the lower the
Figure 1. Nutrient flow on A) a traditional integrated crop/livestock farm and B)
a contemporary system with crops produced on one farm and animals produced on
another farm. (Adapted from Lanyon and Beegle 1993).
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Journal of Contemporary Water Research & Education
Nutrient Management in the Chesapeake Bay
cost of purchased fertilizer; manure was thus an
economic advantage to the farm. In this traditional
system, the main focus was managing to overcome
nutrient depletion as efficiently as possible.
Nutrient excesses were rare and inefficient manure
management was less common because of the
direct economic penalty to the farm. Consequently,
environmental problems from nutrients were not a
widespread concern.
However, after World War II fertilizer usage
became an economical alternative to manure
and legumes in crop production systems. The
local nutrient cycle that was necessary to sustain
the traditional integrated farm was no longer
necessary (Lanyon 1994). Farmers in places like
the Midwest realized that they could produce
larger crops and do it more economically just with
chemical fertilizer. At the same time, farmers in
areas like the Mid-Atlantic U.S. realized that they
could not really compete with corn belt farmers in
crop production, but they could utilize these crops
to increase animal production well beyond what
was possible in the traditional system where they
had to grow their own feed for the animals. This
was a very synergistic relationship resulting in
economic-driven specialization and concentration
of crop and animal production in different areas.
However, an unforeseen consequence of this shift
in the organization of agricultural production was a
major change in nutrient cycling. In the traditional
system, the major nutrient flows were within the
farm with relatively minor inputs and outputs to and
from the farm (Figure 1A). As the more specialized
organization evolved, major nutrient flows beyond
the farm became very significant (Figure 1B).
Large inputs of fertilizer nutrients were
occurring on farms where crops are produced, but
these inputs were balanced by large outputs of
crops leaving the farm. Within this crop production
system there is a strong economic driver for higher
nutrient use efficiency that would directly result
in increased profit from the crops produced. This
higher nutrient use efficiency should also result in
less potential for nutrient losses to the environment
in this system. The crops from these farms are then
marketed to farms in other areas where the animals
are produced. Thus, the large output of nutrients
in the crops from the crop farm then become large
nutrient inputs on the farms where the animals
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are produced. On the animal production farm
the output is the nutrients in the animal products
produced which is again only a small proportion
of the nutrient inputs. The remaining nutrients are
now in the manure produced by the animals. In the
traditional system, these manure nutrients would be
recycled back to where the crops were produced.
However, the crops now come from off the farm
and often from a long distance. Thus, recycling of
the nutrients back to where the crops were produced
is not economically feasible. The most economical
thing to do with the manure is to spread it, and the
large amounts of nutrients it contains, on land near
where the animals are produced. However, because
the animal farm is not producing the feed for the
animals, the land base on the animal farm may be
very small relative to the number of animals on
the farm producing manure. In fact, economics
encourage the farmer to minimize the land base for
the animal farm. Consequently, approximately 75
percent of the nutrients from a large acreage crop
farm somewhere else is now being applied to a
relatively small acreage on the animal farm.
The bottom line is that the nutrients in this
contemporary system no longer cycle. The economic
drivers for this system are resulting in a one-way
flow of nutrients from the fertilizer production to
the crop farms, and finally to the animal farms
where they are ultimately accumulating. There
is a wide variety of evidence of this one way
flow of nutrients. Maguire et al. (2007) provides
a national picture of phosphorus balance that
clearly shows the areas of phosphorus depletion
and accumulations. Nutrient balance summaries
for states of the Chesapeake Bay (Mid-Atlantic
Water Program 2009), showed that the phosphorus
balance for cropland in the Mid-Atlantic states was
an excess of 90.2 million pounds of P in 2007.
This is significantly less than it was in 1987 but
still a very large excess. The cropland nitrogen
balance for the Mid-Atlantic states in 2007 was
an excess of 470.4 million pounds of N. This is
less than it had been in recent years but similar to
what it was in the 1980’s. The declines in N and P
balance have largely been due to reduced fertilizer
use and increased crop yields. Manure N and P saw
only small reductions and this source remains the
dominant source of nutrients affecting the nutrient
balance on cropland in the region.
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Beegle
Current Approaches to Solving the
Ag Nutrient Problem
Unlike on the traditional farm, there is no real
economic driver for high nutrient use efficiency for
the manure nutrients on the animal farm because
the total amount of nutrients in the manure is in
excess of the crop needs (Beegle et al. 2002). The
main economic driver on the animal farm is leastcost disposal of the manure. This encourages excess
application on the minimum amount of land as near
to the animal production facility as practical. The
result is much greater potential for environmental
losses of nutrients. However, the economic costs
of this nutrient loss is borne by the environment,
not the production system. Therefore, unlike in
the traditional system, where economics provided
an indirect but strong incentive for environmental
protection, economics are not providing this
incentive in the contemporary system. In fact, the
economic incentive is to let the environment bear
these costs.
This systemic excess of nutrients in areas with
significant animal production has resulted in a
strategic conflict (Figure 2) between economic
management and environmental protection that
must be recognized if successful solutions are
to be developed and implemented (Lanyon and
Thompson 1996).
The contemporary production system described
above is driven by the economic forces from the
Figure 2. Strategic conflict between economics and
the environment in nutrient management. (Adapted
from Lanyon 2000).
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marketplace, both the economics of production
and the economic decisions of the ultimate
consumer of the animal products. At the same
time, this system is causing an accumulation of
excess nutrients on the animal production farms
that results in a significant environmental output
of the farm. However, this environmental output
is not recognized in the market place, but rather
it is an economic externality and has resulted in
social pressure to reduce the environmental output
of animal farms with little regard for addressing
the real economic cost of the problem.
However, as it became evident that nutrient
pollution from agriculture was a major factor in
the decline in Bay health, the common response
was to assume that poor management by individual
farmers was the cause of the problems. Thus,
beginning with the first Chesapeake Bay initiatives
in the 1980’s when the Bay states committed to
reducing nutrient loading to the Bay by 40 percent
(Shuyler 1993), to the present with the Chesapeake
Bay TMDL (U.S. Environmental Protection
Agency 2010), the primary focus for addressing the
nutrient problems from agriculture was, and is, on
responding to the social pressure for changing the
management behavior of individual farmers. The
issues with regional nutrient imbalances related to
the organization of the animal production systems,
which are beyond the control of the individual
farmer, have not been a significant part of these
efforts. Thus, farmers are being squeezed between
the economic forces from the marketplace and the
social forces from the non-market concerns (Figure
2). While this squeeze has presented challenges
for many farmers, it has also had a significant
impact on farm management over the years and
has resulted in major progress toward meeting the
goals for nutrient reduction in the Chesapeake Bay.
Nitrogen and phosphorus input to the Bay have
been reduced by over 25 percent (Figure 3).
Best management practices to improve nutrient
management have been widely adopted through
major initiatives across the watershed to promote
or require nutrient management plans on farms.
For example, while manure P in Pennsylvania has
remained relatively constant for many years due
to relatively stable animal populations, fertilizer
P has been declining since the beginning of the
Chesapeake Bay Program (Mid-Atlantic Water
Journal of Contemporary Water Research & Education
Nutrient Management in the Chesapeake Bay
7
Figure 3. Progress toward meeting the goals for nutrient reduction in the Chesapeake Bay. Loads
simulated using 5.3.2 version of Watershed Model and wastewater discharge data reported by the Bay
jurisdictions (Chesapeake Bay Program 2011).
Program 2009) as farmers have adopted best
management practices that take greater advantage
of the manure P and thus reduce the need to add
additional fertilizer P into the cropping systems.
Many of the changes like this one were catalyzed
by social pressure, but in the end were economical
for the farmers and thus were widely adopted.
Toward a Sustainable Solution to the
Ag Nutrient Problems in the Bay
However, this progress has not met the expectations
of many and concerns have arisen that the progress
toward meeting the environmental goals for the
Chesapeake Bay has slowed. Many blame this on
the lack of willingness of farmers to continue to adopt
best management practices. However, a more logical
explanation is that as the structure of agriculture has
shifted based on economic incentives toward the more
specialized agricultural production systems and the
resulting systemic nutrient imbalances, the economic
benefits of adoption of further best management
practices have become much less. In fact, for many
modern animal production systems the economics
of improved nutrient management to protect water
quality are decidedly negative.
Further progress toward meeting water quality
goals will require someone to shoulder the costs
that have been an externality in the food production
system, historically borne by the environment.
Whether these costs can be integrated into the
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market place or paid by public funding, it is critical
in any strategy for the Bay if we are to successfully
reduce the environmental impact of nutrients on the
Bay. If these costs could be internalized into the
market place (Figure 4) so that the changes desired
to protect the environment could be integrated
into the economic forces that drive management
decisions, this would be a much more effective
way to achieve change than trying to squeeze
change out by applying social pressure with only
minimal regard for the economics of the system
(see Figure 2). This shifts the emphasis from
trying to force change on one part of the system
to address a problem that benefits the broader
population, to society making strategic decisions
Figure 4. Internalization of environmental costs into
the marketplace would economically reinforce the
changes needed to address concerns with nutrient
pollution from agriculture.
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Beegle
about the actual value, to this broader population,
of protecting the environment. If everyone went
to the grocery store and demanded food grown on
farms that are not causing nutrient pollution, and if
they were willing to pay more for food produced
in this way, the economics would quickly drive
management changes in agriculture to cash in on the
economic opportunity and thus reduce the impact
on the environment. It is similar to marketing of
organically-produced food. Some consumers are
willing to spend more for food produced in a way
that fits with their values, and organic farmers
have figured out how to economically meet that
market demand. A similar outlook is needed with
regard to protecting water quality. The challenge
is how to integrate these environmental costs into
the marketplace. However, when the potential
of increasing food costs to protect the bay is
proposed, it appears today that most people want
a clean Chesapeake Bay, as long as someone else
pays for it.
Author Bio and Contact Information
Douglas Beegle is a distinguished Professor of
Agronomy in the Department of Plant Science at
the Pennsylvania State University. His research and
extension programs focus on whole farm nutrient
management and approaches to implementing nutrient
management policy. He can be reached by email at
[email protected].
References
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management approach for Pennsylvania: Plant
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Lanyon, L.E. and P.B. Thompson. 1996. Changes
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Journal of Contemporary Water Research & Education