日本高清色视频在线视频在,国产香蕉97碰碰视频碰碰看,丰满少妇av无码区,精品无码专区在线,久久无码专区免费看,四虎欧美精品永久地址99,亚洲色无码一区二区三区

您現(xiàn)在的位置: Language Tips> Audio & Video> Special Speed News  
   
 





 
Building a windbreak to protect crops
[ 2008-07-29 10:05 ]

 

This is the VOA Special English Agriculture Report.

Farmers 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.

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.

But 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.

For 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 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. Locally grown trees and plants are best for windbreaks.

If 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.

Windbreaks 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.

windbreak: 防風(fēng)林

(Source: VOA 英語點(diǎn)津姍姍編輯)

 
英語點(diǎn)津版權(quán)說明:凡注明來源為“英語點(diǎn)津:XXX(署名)”的原創(chuàng)作品,除與中國日報(bào)網(wǎng)簽署英語點(diǎn)津內(nèi)容授權(quán)協(xié)議的網(wǎng)站外,其他任何網(wǎng)站或單位未經(jīng)允許不得非法盜鏈、轉(zhuǎn)載和使用,違者必究。如需使用,請與010-84883631聯(lián)系;凡本網(wǎng)注明“來源:XXX(非英語點(diǎn)津)”的作品,均轉(zhuǎn)載自其它媒體,目的在于傳播更多信息,其他媒體如需轉(zhuǎn)載,請與稿件來源方聯(lián)系,如產(chǎn)生任何問題與本網(wǎng)無關(guān);本網(wǎng)所發(fā)布的歌曲、電影片段,版權(quán)歸原作者所有,僅供學(xué)習(xí)與研究,如果侵權(quán),請?zhí)峁┌鏅?quán)證明,以便盡快刪除。
相關(guān)文章 Related Story
 
 
 
本頻道最新推薦
 
Walking in the US first lady's shoes
“準(zhǔn)確無誤”如何表達(dá)
英國新晉超女蘇珊大媽改頭換面
豬流感 swine flu
你有l(wèi)ottery mentality嗎
翻吧推薦
 
論壇熱貼
 
別亂扔垃圾。怎么譯這個(gè)亂字呀?
橘子,橙子用英文怎么區(qū)分?
看Gossip Girl學(xué)英語
端午節(jié)怎么翻譯?
母親,您在天堂還好嗎?

 

<strong id="xdwva"><div id="xdwva"></div></strong>
<label id="xdwva"></label>

<thead id="xdwva"></thead>
    <label id="xdwva"></label>

  1. 日本高清色视频在线视频在,国产香蕉97碰碰视频碰碰看,丰满少妇av无码区,精品无码专区在线,久久无码专区免费看,四虎欧美精品永久地址99,亚洲色无码一区二区三区 久久九九久精品国产日韩经典 国产国语国拍精品 啊v在线观看高清无码 视频一区二区欧美 久久精品爱爱唉爱