首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Desertification is the accumulated result of inappropriate land use and a harsh climate. Over-cultivation exhausts the soil, ove
Desertification is the accumulated result of inappropriate land use and a harsh climate. Over-cultivation exhausts the soil, ove
admin
2015-01-03
54
问题
Desertification is the accumulated result of inappropriate land use and a harsh climate. Over-cultivation exhausts the soil, overgrazing leaves behind little vegetation that protects it from erosion, deforestation destroys the trees that bind the soil to the land and underdeveloped irrigation systems turn croplands salty. The semi-dry lands bordering desert exist in a delicate ecological balance and are limited in their potential to adjust to increased environmental pressures. The causes are multiple and interact in a complex manner. Lacking alternative survival strategies, farmers tend to over-exploit natural resources. Soil nutrients and organic matter begin to diminish once intensive agriculture consumes quantities of nutrients greater than the soil’s natural regeneration capacities.
选项
答案
沙漠化是由于土地使用方式不当和恶劣的气候条件累积而成的。过度种植耗尽了土壤的养分,过度放牧使保护土壤免遭侵蚀的植被所剩无几,砍伐森林毁灭了起固土作用的树木,而落后的灌溉系统使农田变成盐碱地。沙漠周边的半干旱土地的生态平衡十分脆弱,而且对环境压力增加的适应力有限。沙漠化的原因多种多样、相互作用并十分复杂。由于缺少替代的生存手段,农民往往过度利用自然资源。一旦精工细作的农业消耗的营养物数量超出土壤自身的再生能力时,土壤的营养物和有机物就开始减少。
解析
转载请注明原文地址:https://kaotiyun.com/show/eLHO777K
0
研究生英语学位课统考(GET)
相关试题推荐
Theideathatsomegroupsofpeoplemaybemoreintelligentthanothersisoneofthosehypothesesthatdarenotspeakitsname.
Theideathatsomegroupsofpeoplemaybemoreintelligentthanothersisoneofthosehypothesesthatdarenotspeakitsname.
Theideathatsomegroupsofpeoplemaybemoreintelligentthanothersisoneofthosehypothesesthatdarenotspeakitsname.
Theideathatsomegroupsofpeoplemaybemoreintelligentthanothersisoneofthosehypothesesthatdarenotspeakitsname.
Hellobackthere!Thisisme,inthefuture.It’sgreathere.Wefinallyhaverobotsthatdothingsforus,althoughnoneofthe
OurculturehascausedmostAmericanstoassumenotonlythatourlanguageisuniversalbutthatthegesturesweuseareunderst
TheUnitedNationsPopulationFundhaspickedOctober31asthedaytheworldwillbehometo7billionpeople.Forbettera
TheUnitedNationsPopulationFundhaspickedOctober31asthedaytheworldwillbehometo7billionpeople.Forbettera
Sciencehaslonghadanuneasyrelationshipwithotheraspectsofculture.ThinkofGallileo’s17thcenturytrialforhisrebell
Sciencehaslonghadanuneasyrelationshipwithotheraspectsofculture.ThinkofGallileo’s17thcenturytrialforhisrebell
随机试题
男性,20岁,反复四肢抽搐、口吐白沫、意识丧失、大小便失禁2年。脑电图示有癫痫样波发放。下列哪种说法不正确
下列各项中,多源性频发室性期前收缩治疗首选的是
《中华人民共和国民法通则》第7条规定:“民事活动应当尊重社会公德,不得损害社会公共利益,扰乱社会经济秩序。”对这条规定,下列哪些理解不正确?()
压力管道中的工业管道的安装许可类别为GC类压力管道,分为()个级别。
某施工企业结合自身情况确定砌筑“1砖混水砖墙”子目中人工消耗量。已知砌筑小组由3名工人组成,在正常施工条件下,经测算完成10m3砖墙砌筑耗时40小时。则在正常施工条件下,砌筑10m3“1砖混水砖墙”的劳动定额为()工日。
某债券票面金额F=100元,票面收益C=8元,每年支付一次利息,2年后还本。根据以上材料,回答下列问题:当市场利率为8%时,该债券的购买价应当是()元。
爱因斯坦说过:“一个人的价值,应该看他贡献什么,而不应该看他取得什么。”对此理解正确的是()。
2022年3月31日,中共中央政治局常务委员会召开会议,听取“3.21”东航MU5735航空器飞行事故应急处置情况的汇报,就做好下一步工作作出部署。习近平总书记强调,安全生产要坚持(),管行业必须管安全,管业务必须管安全,管生产经营必须
设数据码字为10010011,采用海明码进行校验,则必须加入(2)比特冗余位才能纠正一位错。
Whatisthemainreasonforhavingthefair?
最新回复
(
0
)