瓦楞纸英文土地沙漠化英文介绍Dertification
第一篇：土地沙漠化英文介绍 Dertification
Dertification is a type of land degradation in which a relatively dry land region becomes increasingly arid, typically losing its bodies of water as well as vegetation and wildlife.It is caud by a variety of factors, such as climate change and human activities.Dertification is a significant global ecological and environmental problem.Let’s begin with the areas affected by the dertification Drylands occupy approximately 40–41% of Earth’s land area and are home to more than 2 billion people.It has been estimated that some 10–20% of drylands are already degraded, the total area affected by dertification being between 6 and 12 million square kilometres, and that a billion people are under threat from further dertification.The Sahara is currently expanding south at a rate of up to 48 kilometers per year.But how is the dertification coming into being? Here are some Caus.Dertification is caud by two main categories of factors: natural factors and, more importantly, human activities.The natural factors causing dertification include the fol
lowing: 1.The climate has a major influence through rainfall, solar radiation and wind, which affect the rates of physical and mechanical erosion as well as chemical and biological degradation of soil.2.The relief of a land affects the rate of soil erosion by water.3.The textile, structure, and chemical and biological status of soil are factors determining the soil properties in dry sub-humid zones.Human activities play a crucial role in dertification.The reasons behind the activities are the increasing demand for food due to the rapid population growth, and inappropriate agricultural practices.The following are some of the human activities that cau dertification: 1.Uncontrolled u of fire for hunting or for agricultural clearing.2.Over-exploitation of woody resources, particularly for fuelwood.3.Over-grazing of lective vegetation 4.Over-harvesting which results in abandoned fields 5.Agricultural practices that destroy the soil structure.6.Inappropriate irrigation of soil, leading to waterlogging and abandoned fields eventually.Bad on the above factors, we can e that the soil becomes unsuitable for vegetation growth and is turned eventually into a dert.Here are some environmental impacts of dertification 1.The loss of farmlands.Farmlands are important natural resour
ces.Humans rely on them for food.Dertification results in the loss of farmlands, and significantly threatens the living standard and well-being of people inhabiting the areas concerned.This also leads to social problems such as environmental refugees.2.This breakdown of the environment.Dertification also has rious impact on the natural environment.It breaks down the fragile balance and it reprents the start of a process that destroys the natural and stable ecosystem.3.Another problem is that the results of dertification in turn speed up the natural process of dertification.The erosion of soils, the lowering of the water table and vegetation are all intensifying dertification.How to solve this problem?There are many available solutions.1.Control the population growth by using family planning, in order to decrea the land u capacity
2.The number of grazing and the rate of cultivation should not over the carrying capacity of land.3.Improve the farming and grazing methods, in other to reduce soil erosion and salinization.4.Band the deforestation and over grazing, in order to balance the ecosystem of dert.At the current rate that we are going it looks like it may not be possible to completely stop dertification.But there are some steps that can be taken to slow it dow
原理英语n and in many cas prevent it.Although reversing the process is an option, prevention is a much simpler and more cost-effective solution for dealing with it.And it’s everyone’s responsibilily.Let’s do it from now on.loveaffair
第二篇：我国土地沙漠化及其防治(论文)
张月20093349 宋颖20093350 李智会20093359 钟昀20093371 分工情况：
垃圾分类英文
资料收集：李智会 钟昀 资料整理：宋颖 张月 PPT制作：宋颖 李智会 报告：张月 钟昀 演讲：李智会
deco我国土地沙漠化及其
控制
教 师：唐 永 金
班 级：农 学 09 组 员：宋颖 李智会 钟昀 张月
2011年12月5日我国土地沙漠化及其防治
【关键词】 土地沙漠化 成因 现况 危害 防治 【摘要】
沙漠化作为一个生态问题是1977年联合国沙漠化会议以后才正式广泛采用，其内容为：“土地滋生生物潜力的削弱和破坏，最后导致类似沙漠情况，它是生态系统普遍恶化的一个方面，它削弱或破坏了生物的潜力。”由此可见，沙漠化与沙漠、戈壁不同，沙漠化不能抽调人为活动的实质，沙漠化的实质是人地关系矛盾造成生物或经济生产力下降与丧失，地表呈现类似沙漠景观的土地严重退化过程。沙漠化防治是人地关系相互协调，人与自然和谐相处，改善环境，土地生产力再恢复，经济可持续发展的过程。
【正文】
一．沙漠化的定义last night
白话翻译器是指包括气候变异和人类活动在内的种种因素造成的干旱（arid）、半干旱（mi-arid）和亚湿润旱（dry subhumid）地区的土地退化。
该定义明确了3个问题： ①“沙漠化”是在包括气候变异和人类活动在内的多种因素的作用下产生和发展的； ②“沙漠化”发生在干旱、半干旱及亚湿润干旱区（指年降水量与可能蒸散
量（potential evapotranspiration）之比在0.05至0.65之间的地区，但不包括极区和副极区），这就给出了沙漠化产生的背景条件和分布范围； ③“沙漠化”是发生在干旱、半干旱及亚湿润干旱区的土地退化，将沙漠化置于宽广的全球土地退化的框架内，从而界定了其区域范围。
我国《防沙治沙法》中所称土地沙化，是指主要因人类不合理活动所导致的天然沙漠扩张和沙质土壤上植被及覆盖物被破坏，形成流沙及沙土裸露的过程。
二．沙漠化的成因、危害及现状
1.沙漠化的成因
（1）气候变化异常
有关研究表明，近百年来全球气候变化最突出的特征是温度的显著升高。我国近百年来的温度变化与世界的平均情况基本相似。据研究，1951-1999年中国北方地区最低气温显著升高，暖冬年份连续出现，近50～100年有明显的干旱化趋势；20世纪70年代开始干旱化趋势加快。
我国沙化土地集中分布的西北地区，由于深居大陆腹地，是全球同纬度地区降水量最少、蒸发量最大、最为干旱的地带。气候变暖、降水减少加剧了该区气候和土壤的干旱化。这使得该区的植被盖度降低，土壤结构变的更加松散，加速了土地的沙漠化。另外气候增暖，大范围气候持续干旱，给各种水资源（冰川、湖泊、河流等）带来严重的影响，使冰川退缩、河流水量减少或断流、湖泊萎缩或干涸，地下水位下降。大面积的植被因缺水而死亡，失去了保护地表土壤功能，加速了河道及其两侧沙化土地的扩展及沙漠边缘沙丘的活动，使沙漠化面积不断扩大。
出厂价英语
（2）不合理的开荒
在沙漠化相对集中的西部地区，曾今有大量草地和林地被开垦为耕地。自1995～2000年，其中因开垦草地增加的耕地面积占69.5%，因开垦林地增加的耕地面积占22.4%。由于该区属干旱、半干旱地区，草地和林地被开垦为耕地后，在农闲季节土壤失去了植被的保护，加之技术、社会经济条件限制，造成耕地沙化面积不断扩大。
（3）过度放牧
目前西北地区超载过牧日趋严重，其中新疆、广西、宁夏、内蒙古超载率较高，超载率分别达到了121%、81%、72%及66%。过渡放牧造成了对草地地表的过度践踏，草原地表土壤结构破坏严重，经风吹蚀，大量出现风蚀缺口，牲畜放牧越多的草地，土壤裸露的也越多，形成的沙漠化面积也越大。
（4）不合理的挖采和树木砍伐
结合能近些年来，生态环境相对脆弱的西北地区大规模滥挖发菜、干草和麻黄等野生中药材的事件时有发生。1.9亿亩的草场面积遭到严重破坏，约占内蒙古全部草原面积的18%，有相当部分正处于沙漠化的过程中。其中约0.6亿亩的草场面积被完全破坏且已沙化。由于1.9亿亩草地遭到严重破坏而不能放牧，被迫到其它草场超载放牧的草地要远远大于1.9亿亩，草原负担过重，加速了沙漠化的扩展。滥樵造成植被严重破坏，仅内蒙古伊克昭盟从20世纪60年代到80年代的20多年中，因滥樵而沙化的草场面积就达2000多平方公里。
大学生素质拓展
