Barriers of trees and other plants seem to work best when they let a little wind pass through. Transcript of radio broadcast:
the VOA Special English Agriculture Report.
use different kinds of soil conservation methods to protect their land from
damage by farming and the forces of nature. One important form of soil
conservation is the use of windbreaks.
are barriers formed by trees and other plants. Farmers plant these barriers
around their fields.
Windbreaks stop the wind from blowing
soil away. They also keep the wind from destroying or damaging crops. They are very
important for protecting grain crops.
There have been studies done on
windbreaks in parts of West Africa, for example. These found that grain
harvests can be twenty percent higher in fields protected by windbreaks
compared to fields without such protection.
windbreaks seem to work best when they allow some winds to pass through them.
If the wall of trees and plants blocks the wind completely, then violent air
motions will take place close to the ground. These motions will lift soil into
the air where it will be blown away.
this reason, a windbreak is best if it has only sixty to eighty percent of the
trees and plants needed to make a solid line. An easy rule to remember is that
windbreaks can protect areas up to ten times the height of the tallest trees in
There should be at least two lines in
each windbreak. One line should be large trees. The second line, right next to
it, can be shorter trees and other plants with leaves. Locally grown trees and
plants are best for windbreaks.
the quality of the land is not very good, studies have shown that one kind of
tree that can grow well is the white pine. Another is the loblolly pine.
not only protect land and crops from the wind. Surplus trees can be cut down
and used to provide wood.
Trees reduce the damaging effects of
wind and rain. Their roots help protect soil from being washed away. And trees
do something else -- they can provide grazing animals with shade from the sun.
And that's the VOA Special Agriculture
Report. You can get more information about windbreaks and other forms of soil
conservation at enterpriseworks.org. And you can also learn more about
agriculture at our Web site, voaspecialenglish.com. I'm Jim Tedder.