Each time you apply a pesticide on your
farm a number of things may happen to
that pesticide.The pesticide may be
taken up by plants, or be ingested by
insects or soil organisms, or it may
adhere to soil particles to be carried off
in the air or move in water. There is
always some risk to the environment the
degree of environmental risks depends
upon four factors. Persistence - how long
the pesticide remains active in the
environment. Mobility - how easily the
pesticide can move from where it was
applied. Non-target toxicity - how toxic
the pesticide is to organisms other than
the pest. And volume of use - how much of
that pesticide is used in the
environment. The physical and chemical
properties of pesticides as well as
natural processes influence their
environmental risk. By considering these
properties and processes before you use
a pesticide you will be able to maximise
pest control and minimize environmental
risk. First let's review five properties
of pesticides that can affect their fate
in the environment. Pesticides can be
broken down by organisms, chemical
reactions, and sunlight. This is called
degradation. How fast this happens
depends on the pesticide and the
environmental conditions on your farm. If
the soil is warm and moist for example
microbes quickly consume the pesticide
and turn it into other molecules such
as carbon dioxide and water. Pesticides
that do not break down quickly are
called persistent. An example of a
moderately persistent pesticide is
atrazine which has been found in surface
and groundwater across Ontario.
Pesticides may bioaccumulate or build up
in body tissues such as animal fats.
These pesticides may then bio magnify or
build up in the food chain. Adsorption is
the binding of pesticides onto soil
particles and organic matter. The way a
pesticide binds to the surface of the
soil particle is similar to magnetic
attraction. Soils that are high in
organic matter or clay are the most
adsorptive. A pesticide adsorbed tightly
in the soil may move with soil particles
eroded by wind or water and is less
likely to be degraded by soil
microorganisms.
Pesticides can move into organisms like
plants and insects or structures like
soil or wood similar to the way that
water moves into a sponge and this is
called absorption. Once inside the tissue
of an organism the organism may break
down so that it is no longer harmful to
that organism. This reduces the hazard of
pesticide residues remaining in food.
Pesticides may change into a vapor when
exposed to air similar to how water
evaporates. This is called pesticide
volatility. Once a pesticide volatilizes
it can travel for miles.
The fate of pesticides in the
environment is determined by a
combination of these five properties
plus how pesticides move through the
natural processes of drift, surface
runoff, leaching, and soil erosion. You can
reduce pesticide movement in these
natural processes by your farming
practices. To reduce drift there are many
things you can do such as using nozzles
that produce larger spray droplets or
lowering the boom of your sprayer.
Surface runoff of pesticides can be
reduced by no-till and minimum tillage
practices which also reduce pesticide
movement via soil erosion. Leaching is
the movement of water down through the
soil potentially to tile lines and
surface waters or to ground water. Adsorptive
pesticides are less likely to leach
because they stick to organic matter. To
increase the amount of organic matter in
your soil add manure and crop residues.
You can also prevent pesticides from
entering the environment by handling
pesticides with care. Store pesticides
properly so they do not contaminate
people or the environment. For any
spilled pesticides make sure you clean
it up properly. Call the spills Action
Center for helpful advice. When you're
done spraying correctly dispose of your
empty containers including triple
rinsing and returning them to a
pesticide container collection site. An
integrated pest management approach can
help control pests without pesticides. If
you choose to use a pesticide completely
read the entire product label and check
for environmental precautions. For
instance, you may need to leave a buffer
zone of unsprayed natural vegetation to
protect sensitive water sources or
animal habitat. Or to prevent poisoning
of bees be sure to avoid applying
insecticides on flowering crops or when
bees are foraging.
Before you use a pesticide consider all
the pesticide properties natural
processesand practices you can do
to protect your crops and the
environment.
 
