Disasters in the United States in the 1930s.

/kloc-in the 0/9th century, the United States adopted the policy of encouraging people to emigrate to the semi-arid western prairie for land reclamation, and reclaimed 900,000 square kilometers of land in just 30 years from 1860 to 1890. However, excessive reclamation has caused large-scale land desertification. In the 1930s, sandstorms gradually formed in the United States, 1932 14 times, 1933 38 times, and finally developed into a disastrous sandstorm in the spring of 1934. Dust storms reduce wheat production in the United States 1/3. 1935, a black storm that shocked the world was formed. A large amount of black soil on the surface of the newly cultivated land was wrapped by sandstorms, forming a black dragon with a length of 2 400 kilometers from east to west, a width of 1 440 kilometers from north to south and a height of about 3 kilometers. It swept two-thirds of the United States in three days and threw 300 million tons of fertile topsoil into the Atlantic Ocean. Where the black storm passed, farmland, wells and roads were destroyed, streams and rivers dried up, and 6.5438+0.6 million farmers fled the western region. This year, American agriculture suffered heavy losses, and grain production was reduced by half. After that, the United States had to formulate a special "agricultural revival plan", implement the no-tillage method, establish one of the four major afforestation projects in the world-the "Roosevelt Ecological Project" implemented by the National Resource Guard, and planted a shelter belt with a width of 100 miles along the west longitude 100 degrees, running through the whole United States. This prevented the black storm from continuing to wreak havoc and gradually restored the natural environment in this area.

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