Luyện Nghe Tiếng Anh
Farmers different kinds of soil conservation methods to protect their from damage by farming and the forces of nature. One important form of soil conservation is the use windbreaks.
Windbreaks are barriers formed by trees and plants with many leaves. Farmers plant them in around their fields.
Windbreaks stop the wind blowing soil away. They also keep the wind destroying or damaging crops. They are very important growing grains, such as wheat.
There have been studies on windbreaks in parts of West Africa, for example. These found that grain harvests can be twenty percent in fields protected by windbreaks compared to fields without protection.
However, windbreaks seem to work when they allow a little wind to pass through. If the wall of trees and plants stops wind , then violent air motions will take place close to ground. These motions will lift soil into the where it will be blown away.
For reason, a windbreak is best if it has only to eighty percent of the trees and plants needed make a solid line.
An easy rule remember is that windbreaks can protect areas up to times the height of the tallest trees in the .
There should be at least two lines in windbreak. One line should be large trees. second line, right next to it, can be shorter and other plants with leaves. Locally grown trees plants are best for windbreaks.
Windbreaks not protect land and crops from the wind. They also provide wood products. These include wood for and longer pieces for making fences.
You get more information about windbreaks and other forms of conservation from the group Volunteers in Technical Assistance. is part of EnterpriseWorksVITA/, on the Web at enterpriseworksorg..
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And that's the VOA Special Development Report, written by Garriott. I'm Steve Ember.
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