英文,沙漠化,急用!我要一些英文的回答．急用!关于沙漠化的一些问题．比如说危害,原因,是否是全球问题,怎样防治．要一些简短的,一小段就行．

英文,沙漠化,急用!我要一些英文的回答．急用!关于沙漠化的一些问题．比如说危害,原因,是否是全球问题,怎样防治．要一些简短的,一小段就行．
英文,沙漠化,急用!
我要一些英文的回答．急用!
关于沙漠化的一些问题．比如说危害,原因,是否是全球问题,怎样防治．要一些简短的,一小段就行．

英文,沙漠化,急用!我要一些英文的回答．急用!关于沙漠化的一些问题．比如说危害,原因,是否是全球问题,怎样防治．要一些简短的,一小段就行．
Desertification is the degradation of land in arid and dry areas,resulting from human activities and influenced by climatic variations.The primary reasons for desertification are overgrazing,over cultivation,increased fire frequency,overdrafting of groundwater,increased soil salinity,and global climate change.A major impact of desertification is loss of productive capacity.In Africa,for instance,if current trends of soil degradation continue,the continent might be able to feed just 25% of its population by 2025.Desertification is also widespread in many areas of China.The populations of rural areas have rapidly increased.While there has been an increase in livestock,the land available for grazing has decreased.Also the importing of European cattle,which have higher food intakes,has made things worse.A number of solutions have been tried in order to reduce the rate of desertification and regain lost land.Oases and farmlands in windy regions can be protected by planting tree fences or grass belts.Sand that manages to pass through the grass belts can be caught in strips of trees planted as wind breaks 50 to 100 meters apart adjacent to the belts.Small plots of trees may also be scattered inside oases to stabilize the area.On a much larger scale,a "Green Wall of China",which will eventually stretch more than 5,700 kilometers in length,nearly as long as the Great Wall of China,is being planted in north-eastern China to protect "sandy lands" – deserts created by human activity.

Desertification is a process. It changes productive land into useless land. One example of desertification is when a desert spreads into nearby cropland. In time, the cropland becomes an extension of ...

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Desertification is a process. It changes productive land into useless land. One example of desertification is when a desert spreads into nearby cropland. In time, the cropland becomes an extension of the desert.
段意大概是讲沙漠化的形成，传播。
But that is not the only way farmers lose fertile soil.
但是那并不是农民们失去肥沃土壤的唯一原因。
Long dry periods, warmer temperatures and the removal of trees can all lead to the loss of good cropland. Floods can remove fertile topsoil and begin a process resulting in the loss of planting areas.
沙漠化的形成，原因。
Another danger to good land is poor farming methods. Farmers should avoid continually planting crops in the same places, or letting animals feed year after year on the same lands.
措施之类的东西。
Countries from Guatemala to Greece to Vietnam are working against the loss of cropland. Africa especially faces the risk of desertification.
国际面对沙漠化的概况。
Nigeria, for example, says it loses three hundred fifty thousand hectares of usable land each year. Hills of sand now cover places where people once lived.
沙漠化给人们带来的危害只类的。
When cropland turns to desert, people move to other places for better land and better jobs. This migration can cause political and social tensions.
危害导致的一系列问题。
A nonprofit organization in Nigeria is working to bring public attention to the problem. The group is called Fighting Against Desert Encroachment, or FADE.
一些抗击沙漠化的组织
Newton Jibunoh is a retired soil engineer who started this group in the year two thousand. He says desert encroachment could cause widespread hunger.
沙漠化发展倾向，
Newton Jibunoh is currently leading a delegation to thirteen African countries to discuss the dangers of losing farmlands. In northern Nigeria, the group organized a competition between schools in seven areas. The goal was to see who could plant the most trees.
抗击沙漠化的目标，具体措施。
Trees are often cut down for fuel wood. But lines of trees around cropland can catch blowing sand. In addition, tree roots can hold soil in place. Even within a desert, trees can be planted as borders around grassy areas.
情况。
For many years, China has been building a wall of trees in the northern part of the country. The goal is to stop the Gobi Desert from extending toward Beijing. The Great Green Wall will extend about five thousand kilometers. Completion is expected in two thousand fifty.
中国抗击沙漠化的措施。
And that's the VOA Special English Agriculture Report, written by Jerilyn Watson. For more stories about agriculture, go to voaspecialenglish.com for transcripts, MP3s and podcasts of our reports. I’m Bob Doughty.
出自VOA报道。想获得更多信息可去voaspecialenglish.com/。

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在干旱和亚干旱地区（也包括一部分亚湿润地区），在干旱多风和具有疏松沙质地表的情况下，由于人类不合理的经济活动，使原非砂质荒漠的地区，出现了以风沙活动、沙丘起伏为主要标志的类似沙漠景观的环境退化过程。地球上受到沙漠化影响的土地面积有3800多万平方公里，目前，全世界每年约有600万公顷土地发生沙漠化。沙漠化问题涉及的范围之广，已引起全世界关注。产生沙漠化的自然因素主要是干旱、地表为松散砂质沉积物和大...

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在干旱和亚干旱地区（也包括一部分亚湿润地区），在干旱多风和具有疏松沙质地表的情况下，由于人类不合理的经济活动，使原非砂质荒漠的地区，出现了以风沙活动、沙丘起伏为主要标志的类似沙漠景观的环境退化过程。地球上受到沙漠化影响的土地面积有3800多万平方公里，目前，全世界每年约有600万公顷土地发生沙漠化。沙漠化问题涉及的范围之广，已引起全世界关注。产生沙漠化的自然因素主要是干旱、地表为松散砂质沉积物和大风的吹扬等；人为因素主要是过度放牧、过度垦殖、过度樵柴和不合理地利用水资源等。沙漠化是环境退化的现象，是一种逐步导致生物性生产力下降的过程，包括发生、发展和形成三个阶段。发生阶段（初期阶段）是潜在性沙漠化，仅存在发生沙漠化的基本条件，如气候干燥、地表植被开始被破坏，并形成小面积松散的流沙等；发展阶段，地面植被开始被破坏，出现风蚀，地表粗化、斑点状流沙和低矮灌丛沙堆，随着风沙活动的加剧，进一步出现流动沙丘或吹扬的灌丛沙堆；形成阶段地表广泛分布着密集的流动沙丘或吹扬的灌丛沙堆，其面积占土地面积50％以上。沙漠化的危害是破坏土地资源，使可供农牧的土地面积减少，土地滋生能力退化，植物量减少，土地载畜力下降，作物的单位面积产量降低。沙漠化已给许多国家和地区的农业、牧业和人民生活财产造成严重损失。

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