arable land
Cultivated land refers geography to the land that can be used to grow crops. About 31 million hectares of land on the planet's 48 million square kilometers are arable land, but the current arable land is losing at a rate of 100,000 square kilometers per year. The main reason for the loss of arable land is the forest logging, the current forest development mainly occurs in the tropical areas over the development of the rain forest. Forest outbreaks can sometimes lead to desertification, such as the central plateau of Madagascar, which has led to severe desertification due to excessive migration. Another smaller but important reason is the river water control project, the river side of the arable land because of the lack of soil brought about by the soil can not back up the erosion of the part of the land and then slowly lost. And a large part of the arable land is located in the vicinity of many rivers, such as the Nile, the Mississippi River, the Tigris River and the Euphrates River, the Yellow River, the Yangtze River, the Amazon River, the Ganges River and the Rhine River. ...