AGRICULTURE REPORT - Soil Conservation Methods（在线收听）

AGRICULTURE REPORT - February 5, 2002: Soil Conservation Methods

By Gary Garriott
04 Feb 2002, 18:39 UTC

This is the VOA Special English Agriculture Report.

Soil conservation efforts protect soil from wind and water that can blow or wash it away. Good soil produces
food crops for both people and animals.

One important form of soil conservation is the use of windbreaks. Windbreaks are barriers formed by trees and
other plants with many leaves. Farmers plant them in lines 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
growing grains, such as wheat.

For example, in parts of West Africa, studies have shown that grain harvests can be
twenty per cent higher on fields protected by windbreaks compared to those without
such protection.

Windbreaks are effective when a wall of trees and other plants blocks the wind. The
windbreaks should also limit violent motions of the wind to those areas closest to the
windbreak.

However, windbreaks seem to work best when they allow a little wind to pass through. If
the wall of trees and plants stops wind completely, then violent air motions will take
place close to the ground. These motions cause the soil to lift up into the air where it will

be blown away. For this reason, a windbreak is best if it has only sixty to eighty per cent 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 the
windbreak.

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.

Windbreaks not only protect land and crops from the wind. They can also provide wood products. These include
wood for fuel and longer pieces for making fences. Locally grown trees and plants are best for windbreaks.

You can get more information about windbreaks and other forms of soil conservation from the group Volunteers
in Technical Assistance. VITA is an organization that helps people around the world use science and technology
to solve problems.

You can contact VITA through the Internet at its World Wide Web address, w-w-w dot v-i-t-a dot o-r-g.

This Agriculture Report was written by Gary Garriott.

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