First, soil erosion. Typical areas in China: Loess Plateau, southern hilly areas, reasons:
1, natural causes: concentrated precipitation and heavy rain in monsoon climate; The surface vegetation is scarce; Loess Plateau with loose soil.
2. Man-made reasons: vegetation destruction; Irrational farming system; Mining.
Second, the problem of desertification. Typical areas of China: Northwest China (Xinjiang, Qinghai, Inner Mongolia, etc. ), the reason:
1, natural causes: global warming, strong evaporation; Located inland, with little precipitation; Rodents; Locust disaster.
2. Human factors: overgrazing; Excessive logging; Overculture; Unreasonable utilization of water resources; Improper protection of traffic lines and other projects.
Third, drought and water shortage. Typical areas in China: North China, Northwest China, Middle and Lower Reaches of the Yangtze River, Genesis (North China);
1, natural reasons: temperate monsoon climate, less annual precipitation and small river runoff; The variability of precipitation is large; Evaporation is very strong in spring.
2. Human factors: dense population, developed industry and agriculture, and large water demand; Serious water pollution; Too much waste and low utilization rate; Water consumption for spring planting is large in spring.