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
Environmental Science What happened during the agricultural expansion in the southern Great Plains?
Environmental Science What happened during the agricultural expansion in the southern Great Plains?
admin
2014-09-29
56
问题
Environmental Science
What happened during the agricultural expansion in the southern Great Plains?
Environmental Science
Narrator
Listen to part of a lecture in an environmental science class.
Professor
OK, now let’s talk about another environmental concern—soil erosion. It’s a major problem, all around the world. Sometimes erosion damages soil so severely that the land can no longer be cultivated and it’s just abandoned. That happened in a big way right here in the United States. Some of you have probably read the novel The Grapes of Wrath. And maybe you remember that the story took place in the 1930s, during the time of what was called the Dust Bowl.
Dust Bowl is a term we use to describe an ecological and human disaster that took place in the southern Great Plains region. For nearly eight years, dust and sand blew across the area and covered everything. It was so bad it even made breathing and eating difficult. . . and farmers could only look on helplessly as their crops were destroyed and the land .. . and their lives ... ruined.
Now, there’d always been droughts and strong winds in that region. But that was OK because the native grasses had deep roots in the ground that were able to hold the soil in place. So the wind wasn’t able to, you know, erode the soil too badly. This changed, though, between 1900 and 1930. Agriculture was expanding rapidly then, and lots of farmers in the southern Great Plains wanted to grow wheat and other crops they could sell for cash—uh, crops that would be profitable. So they ripped up much of the grassland to plant these crops like wheat, which don’t hold the soil down nearly as well. At the same time, livestock—uh, cattle, too many of them—were feeding on grasses in the area and damaging a lot of the grassland. So these animals caused even more erosion of the soil.
It didn’t help that many of the actual owners of the land were not living anywhere near the area—a lot of the landowners lived way back east, and rented out the land to local people who lived on the land and worked on it, but, um, didn’t have much reason to take really good care of it. I mean, it wasn’t their land, right? The tenant farmers weren’t really interested in conserving someone else’s soil—not for the long term, anyway.
Also, some thought the land couldn’t really be damaged—you know, that the soil was so rich and deep that... it didn’t matter if the topsoil, the soil on the surface, blew away. They thought they could just plow up more. But they were wrong. Good top-soil takes a long time to form—it can literally take thousands of years to create good topsoil that will grow vegetation—and a very short time to ruin it. So after only a few years of excessive plowing, the land pretty much couldn’t be farmed anymore. And people moved on to other places and let the old areas just sit there. And when they didn’t plant anything on that land, that made it vulnerable to even more erosion. So it was kind of a vicious cycle, you could say.
Another problem, ironically, was that advances in technology were actually destroying the land, instead of improving it. A lot of farmers were using huge new tractors that dug deep into the ground and tore up a lot of the soil.
And then, of course, there was the weather. You know, when people look back on the Dust Bowl era, they tend to blame the drought—the lack of rain between 1934 and 1937. We can’t ignore the drought—I mean, it was the worst on record at the time and did help bring on this disaster. But—without the soil destruction—the drought alone wouldn’t have resulted in the devastation we call the Dust Bowl. It was poor farming techniques that made that happen.
Since then, though, we’ve paid more attention to trying to prevent a future Dust Bowl. One thing Congress did was enact a massive government effort to improve soil conservation, called the Soil Erosion Act. Under this law, large stretches of land in the southern Great Plains were identified as being at risk for erosion and were taken out of production and turned into permanent grassland. What that did—by protecting the land from excessive farming—was to stabilize the soil. Also, the Soil Erosion Act helped educate farmers to practice better soil conservation techniques, like reducing how often they plowed and using better equipment that would, you know, minimize damage to the soil structure.
选项
A、People improved the soil by planting wheat.
B、Raising cattle and other livestock became less common.
C、Most of the landowners became farmers.
D、Much of the grassland was destroyed.
答案
D
解析
转载请注明原文地址:https://kaotiyun.com/show/sHfO777K
0
托福(TOEFL)
相关试题推荐
Completethenotesbelow.WriteNOMORETHANTWOWORDSforeachanswer.NecessaryimprovementstotheexistingSelf-
Completetheformbelow.WriteONEWORDAND/ORANUMBERforeachanswer.
WhatdoSharonandXiaoLiagreewasthestrongestaspectoftheirpresentation?
Whatinformationwasgivenbyeachwriter?ChooseyouranswersfromtheboxandwritethelettersA-FnexttoQuestions24-27.A
Completethenotesbelow.WriteONEWORDONLYforeachanswer.EngineeringforsustainabledevelopmentTheGreenhou
ChooseTWOletters,A-E.WhatTWOthingsdoesthearticlesayaboutgoal-setting?AMeetingsshouldstartwithaclearstatemen
WhatrulesapplytotakingdifferentobjectstotheCentre?Matcheachobjectwiththecorrectrule,A-C.Writethecorrectlett
Whatfeaturedothespeakersidentifyforeachofthefollowingcourses?ChooseFIVEanswersfromtheboxandwritethecorrect
Completethetablebelow.WriteNOMORETHANTWOWORDSAND/ORANUMBERforeachanswer.Talkingaboutthehistoryofbikes
Choosethecorrectletter,A,BorC.Togatherdata,theprofessorasksJane
随机试题
水泥混凝土面层实测项目中属于关键项目的有()。
A、Howtheycanbereducedinnumber.B、Whytheirnumbersaresohigh.C、Whatpercentagetheyaccountfor.D、Iftheirpercentage
轻度水肿的特点是
患者,男,52岁。因进行性吞咽困难半年余就诊,X线钡餐透视诊断为食管癌。为了解肿瘤向外扩散情况,该患者还需行的检查是
某机电产品国际招标项目,招标文件从3月1日开始发售,投标截止时间为3月21日,如果潜在投标人对招标文件有异议,最迟应当在()向招标人提出。[2012年真题]
关于事业单位无形资产的处置,下列会计处理中,错误的是()。
服务技能可以分为()。
简述教学过程的基本阶段。
贫困的要素不仅包括物质和收人水平指标,还包括能力指标,即人类基本能力和权利的剥夺。权利贫困就是缺乏政治、经济、文化和社会基本人权的一种贫困状态。权利贫困是贫困的核心,物质贫困是贫困的具体表现,权利贫困是造成物质贫困的根本原因。根据上述定义,下列选项不属于权
表达式operator+(x,y)还可以表示为______。
最新回复
(
0
)