雅思阅读背景知识之尘暴区Dust Bowl

雅思阅读背景知识之尘暴区Dust Bowl为大家带来雅思阅读中关于地质学话题的一篇阅读文章的背景解析，主要内容为地质学中一种叫做尘暴现象的科普，这个经常出现尘暴的地区也叫做Dust Bowl，尘暴区。下面就让我们一起来看看。

这篇雅思阅读背景材料主要讨论的是Dust Bowl也就是风沙中心的问题，也是美国中部大平原南部地区的代号。这个地区为什么会有这样的一个代号呢，有什么特点呢?

Dust Bowl, common name applied to a large area in the southern part of the Great Plains region of the United States, much of which suffered extensively from wind erosion during the 1930s. The area included parts of Kansas, Oklahoma, Texas, New Mexico, and Colorado. In its original state, the region was covered with hardy grasses that held the fine-grained soil in place in spite of the long recurrent droughts and occasional torrential rains characteristic of the area. A large number of homesteaders settled in the region in the 30 years before World War I, planting wheat and row crops and raising cattle. Both of these land uses left the soil exposed to the danger of erosion by the winds that constantly sweep over the gently rolling land. Beginning in the early 1930s, the region suffered a period of severe droughts, and the soil began to blow away. The organic matter, clay, and silt in the soil were carried great distances by the winds, in some cases darkening the sky as far as the Atlantic coast, and sand and heavier materials drifted against houses, fences, and barns. In many places 8 to 10 cm (3 to 4 in) of topsoil were blown away. Many thousands of families, their farms ruined, migrated westward; about a third of the remaining families had to accept government relief.

尘暴是美国大平原地区南部一大片地区的统称，在20世纪30年代，这些地区的大部分地区都遭受了风蚀。该地区包括堪萨斯州、俄克拉荷马州、德克萨斯州、新墨西哥州和科罗拉多州的部分地区。在最初的状态下，该地区覆盖着耐寒的牧草，尽管该地区经常发生干旱和偶尔的暴雨，但这些草保持了土壤的细粒性。在第一次世界大战前的30年里，大量的庄园主定居在这个地区，种植小麦、种植庄稼、养牛。这两种土地用途都使土壤暴露在风的侵蚀下，风不断地吹拂着平缓起伏的土地。从20世纪30年代初开始，该地区遭受了一段时间的严重干旱，土壤开始流失。土壤中的有机物、粘土和淤泥被风带到很远的地方，有时甚至使大西洋海岸的天空变暗，沙子和更重的物质被吹到房屋、篱笆和谷仓上。在许多地方，8到10厘米(3到4英寸)的表土被风吹走了。成千上万的家庭，他们的农场被毁，向西迁移;剩下的三分之一的家庭不得不接受政府的救济。

Beginning in 1935 intensive efforts were made by both federal and state governments to develop adequate programs for soil conservation and for rehabilitation of the Dust Bowl. The measures taken have included seeding large areas in grass; 3-year rotation of wheat and sorghum and of lying fallow; the introduction of contour plowing, terracing, and strip planting; and, in areas of greater rainfall, the planting of long “shelter belts” of trees to break the force of the wind. Dry spells in the 1950s, '60s, and late '70s were responsible for recurrences of dust storms in the region.

从1935年开始，联邦政府和州政府都在加紧努力，为土壤保护和沙尘暴的恢复制定适当的计划。采取的措施包括在大面积的草地上播种;小麦、高粱轮作三年，休耕三年;引入等高线耕作、梯田和条带种植;而且，在降雨量较大的地区，种植长长的“防护林”来抵御风力。20世纪50年代、60年代和70年代末的干旱期是该地区沙尘暴复发的原因。

In the 1930s and 1940s, the region also received two waves of major migrations: that of farm families from the southern Great Plains migrating west to escape the Dust Bowl, and that of African Americans moving out of the American South. During World War II (1939-1945) the need for labor, especially in ship and aircraft production, boosted the population even more. The population of Los Angeles County jumped from 3 million to 4.7 million between 1940 and 1950.

20世纪30年代和40年代，该地区还经历了两波大规模移民潮:一波来自大平原南部的农民家庭为了躲避沙尘暴向西迁移，另一波来自美国南部的非洲裔美国人。在第二次世界大战(1939-1945)期间，对劳动力的需求，尤其是对船舶和飞机生产的需求，进一步增加了人口。从1940年到1950年，洛杉矶县的人口从300万猛增到470万。

以上就是雅思阅读背景知识之尘暴区Dust Bowl的全部内容，像地质学这样的专业性很强的文章，同学们更应该事先对背景知识进行扫盲。