题目为Serious effects of iron loss的英语作文

题目为Serious effects of iron loss的英语作文
题目为Serious effects of iron loss的英语作文

题目为Serious effects of iron loss的英语作文
A serious threat to farmers in many parts of the world is erosion.If a large area of land is cleared of trees and bushes and is then badly treated by the farmer,the rain and winds may gradually wash away,or blow away,much of the fertile top-soil.When this happens,crops of corn of grass become weaker and weaker until nothing much will grow at all,If erosion is allowed to continue,it will turn good farm land into a desert.
The first really bold attempt to do this was started by the Government of the United States of America in 1922.This experiment set a pattern for the world.The district where the experiment was carried out was the area watered by the Tennessee River in the U.S.A.The total area,about the size of England and Scotland combined,contained four million five hundred thousand people.Floods and bad farming over the years had ruined a land that had once been rich,and had made it miserably poor.
Big dams were built across the Tennessee river and its tributaries.In the rainy season there was plenty of water,and the dams stored it for use during the water which could be used for generating electricity.The Tennessee Valley Authority staff also helped the farmers to fertilize the soil,and to plant wind-breaks which would turn the force of the wind upwards away from the land.They taught the farmers to plough across the slopes of the hills (not upwards and downwards)in order to keep the rain-water in the land; and they tried to change the old methods of farming into modern ways.
The great success of the Tennessee Valley scheme has led to similar schemes elsewhere.In many places today rivers are dammed to control floods,generate electricity,and store water for the land in the dry season.But there is much more to do.