United States;
Environmental Protection
Agency -1 :
Office of Water
(4503F);:
EPA-841-F-96-004f=
March 1996
Nohpoint Pointers
Understanding and managing nonppint source pollution in your community.
Managing Nonpoinl
Source Pollution
f rom AgriGuIture
The United States has _mpre than 330 million acres of agricultural land',,
that produce an abundantsupply of low-cost/nutritious food^ feed, and
- fibre. American agriculture is noteds worldwide for its high productivity,
quality, and efficiency in delivering goods to the consumer. However, when
improperly managed, agricultural activities can affect water quality. _
-. The most recent National Water Quality Inventory-tepoxte that agricultural
nonpoint source (NFS) pollution is the leading source of water quality ~"
impacts to surveyed rivers and lakes, the third largest source of impair--~ ;
ments to surveyed estuaries, and also a major contributor to ground-
water contamination and wetlands_degradation.
Agricultural activities that
.cause NFS pollution include
confined animal facilities, grazing,
plowing, pesticide spraying,
irrigation, fertilizing/planting, and
harvesting. The major agricultural
'NFS pollutants that result from - =
these activities are sediment,
" Agricultural activities that
caUse NFS pollution can result .
from confined animal facilities,
grazing, plowing, pesticide:-
spraying, irrigation, fertilizing/
planting, and harvesting..
nutrients, pathogens, pesticides,
and salts. Agricultural activities
also can damage habitat and stream channels. Impacts on surface watered
ground water can be ^minimized by properly managing activities that can
cause NFS pollution. •'-".- - - /"
~~ ~ Numerous government programs are available to help people design and
pay for management approaches to prevent and control NFS pollution. For
example, over 40 percent of section 319 Clean Water Act grants were used to
control agricultural NFS pollution. Also, sevefalJUCS. Department of Agri-
culture and state-funded programs provide cost-share, technical assistance,
and economic incentives to implement NFS pollution management prac--
tices. li/Iany people use their own resources to..adopt technologies and
practices to limit water quality impacts. . , -
-. Managing Sedimentation. Sedimentation occurs when wind or water
runoff carries soil particles from an area/such as a farm field,,and transports
them to a water body, such as a stream or lake. Excessive sedimentation '"
clouds the water, which reduces the amount of siinlight reaching aquatic
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RELATED PUBLICATIONS
• Additional fact sheets in the
Nonpoint Pointers series
(EPA-841-F-96-004)
• Agriculture anc[ Wetlandsj A
Compilation bFFactsheets"
- (EPA-5Q3/9-92-PP3)
« Alternative Agriculture,
' National Research Council,
,— National Academy Press,
== Washington, DC 1989
• Guidance Specifying
raanagemenlMeasures for
Sources of Nonpoint Pollu-
tion in Coastal Waters,
Chapter 2 (EPA-840-B-92-
002)
* Journal of Sojl and Water
Conservation, Vol. 45, No. 1,
Jan/Feb 1990 (EPA-841-N-
90-100)
* Livestock Grazing on
Western Riparian Areas,
EPA Region 8, Denver, CO
« The Quality of Our Nation's
Water: 1994 (EPA-841-8-95-
004)
• Soil And Water Quality: An
Agenda for Agriculture,
National Research Council,
National Academy Press,
Washington, DC, 1993
* USDA National Resources
Inventory, Natural Re-
sources Conservation
Service
To order any of the above EPA
documents call or fax the
National Center for Environmen-
tal Publications and Information.
Tel (513)489-8190
Fax (513) 489-8695
FOR MORE INFORMATION
U.S. Environmental Protection
Agency
Nonpoint Source Control Branch
Washington DC 20460
Internet Address:
http://www.epa.gov/owow/nps/
index.html
plants; covers fish spawning areas and food supplies; and clogs the gills of
fish. In addition, other pollutants like phosphorus, pathogens, and heavy
metals .are often attached to the soil particles and wind-up in the water
bodies with the sediment. Farmers and ranchers can reduce erosion and
sedimentation 20 to 90 percent by applying management measures to
control the volume and flow rate of runoff water, keep the soil in place, and
reduce soil transport.
Managing Nutrients. Nutrients such as phosphorus, nitrogen,-and
potassium in the form of fertilizers, manure, sludge, irrigation water, le-
gumes, and crop residues are applied to enhance production. When they are
applied in excess of plant needs, nutrients can wash into aquatic ecosystems
where they can cause excessive plant growth, which reduces swimming and
boating opportunities, creates a foul taste and odor in drinking w,ater, and
kills fish. In drinking water, high concentrations of nitrate can cause
methemoglobinemia, a potentially fatal disease in infants also known as
"blue baby syndrome." Nutrient management plans can help maintain high
yields and save money on the use of fertilizers^while reducing NFS pollu-
tion. :
Managing Confined Animal Facilities. By confining animals to areas or
lots, farmers and ranchers can efficiently feed and maintain livestock.. But
these confined areas become major sources of animal waste. Runoff from
poorly managed facilities can carry pathogens (bacteria and viruses),
nutrients, and oxygen-demanding substances that contaminate shellfishing
beds and other major water quality problems. Ground water can also be
contaminated by seepage: Discharges can be limited by storing and manag-
ing facility wastewater and runoff with an appropriate waste management
system. , " ,
Managing Irrigation. Inefficient irrigation can cause water quality
problems. In arid areas, for example, where rainwater does not carry resi-
dues deep into the soil, excessive irrigation can concentrate pesticides,
nutrients, disease-carrymg microorganisms, and salts-all of which impact
water quality-in the top layer ,of soil. Farmers can control these effects .by-
improving water use efficiency. Actual crop needs can be measured with a
variety of equipment. "
Managing Pesticides. Pesticides, herbicides, and fungicides are used to
kill pests and control the growth of weeds and fungi. These .chemicals can~
enter and contaminate water through direct application, runoff and wind
transport. They can kill fish and wildlife, poison food'sources, and destroy
animal habitat. Integrated Pest Management (IPM) techniques based on the
specific soils, climate, pest history, and crop for a particular field can limit
pesticide use and manage necessary applications to minimize pesticide
movement from the field.
Managing Livestock Grazing. Overgrazing exposes soils, increases
erosion, encourages invasion by undesirable plants, destroysiish habitat,
and reduces the filtration of sediment necessary for building streambanks,
wet meadows, and flopdplains. To reduce the impacts of grazing on water
quality, farmers and ranchers can adjust grazing intensity, keep livestock out
of sensitive areas, provide alternative sources of water and shade, and
revegetate rangeland and pastureland. . ... .
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