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1 |
Designing
Buffers for Trapping Effieciency |
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6 |
Pesticide
Trapping By Buffers |
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2
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Informational
Sources |
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7 |
Regional
Considerations |
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3 |
Impact
of Buffers |
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8 |
Summary |
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4 |
Integrating
Buffers with BMP's |
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9 |
Types
of Buffers |
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5 |
Maintenance |
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Conservation buffers
can be used in a systems approach to help manage soils, water, nutrients,
and pesticides for sustainable agricultural production which minimizes
environmental impact. Buffers have long been a staple in conservation
systems designed to prevent erosion and trap sediment and nutrients
from field runoff. They also provide other benefits such as wildlife
habitat improvement, streambank protection, and farming safety.
Many studies have been conducted to document these benefits and
to provide guidance in designing buffers for these purposes. But
do buffers work to reduce pesticide losses?
Rainfall or irrigation
can cause pesticides to run off the surface of treated fields. Edge-of-field
losses can range from less than one percent of the amount applied
to as much as ten percent (Wauchope, 1978). Losses are greatest
when severe rainstorms occur soon after pesticide application. Edge-of-field
concentrations of pesticides in surface runoff can range from less
than 1 part per billion (ppb) to 1 part per million (ppm) or more.
Until recently,
few studies had been conducted to measure the effectiveness of buffers
in trapping pesticides in runoff. Physical properties of pesticides
affect their behavior and transport. Some pesticides are highly
adsorbed to soil particles and are carried primarily adsorbed to
eroded sediment. Trapping of these pesticides by buffers should
be very similar to sediment trapping. However, some pesticides are
only moderately adsorbed to soil particles, and are carried off
fields primarily dissolved in water. In order for buffers to be
effective in trapping this type of pesticide, either water infiltration
into the buffer must occur, carrying the chemical into the soil,
or chemical must be removed from solution flowing over the soil
surface by contact with soil or vegetation. Most studies indicate
that an increase in water infiltration is the most important factor
in trapping these pesticides.
This booklet will
examine current knowledge of how conservation buffers can be most
effectively used to reduce pesticide losses to water. Studies specifically
measuring pesticide trapping by buffers will be reported, as well
as relevant studies on effectiveness of buffers in trapping sediment
and increasing water infiltration. The effectiveness of buffers
in reducing pesticide losses will depend on the properties of the
specific pesticide, the design and maintenance of the buffer, and
local climate, weather, and soil conditions. When combined with
specific local input from sources such as the National Resource
Conservation Service (NRCS), this booklet will provide guidance
to those providing advice and assistance to farmers and landowners
installing conservation buffers. Other Best Management Practices
which improve management and reduce losses of pesticides and can
be used in combination with buffers will also be discussed.
Whole Conservation
Buffers Document
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