Desertification
Desertification refers to the phenomenon of emergence of dry land where trees are dry due to weather changes. It happens when a village or an oasis is buried by sand dunes that are overpowering, or when natural vegetation is lost due to overfishing, arson, or excessive greening, and artificial greening is not successful. Wide-scale deforestation in the upper reaches of the Amazon River, and agricultural policy failures in many African countries. Desertification is taking place in northwestern China, devouring farmland. The causes of desertification are divided into natural factors and anthropogenic factors. First, natural factors include drought and dryness. Drought or dryness occurs when the rainfall is not high enough in the high-pressure zone, or in places where the clouds can not reach the high mountains. Anthropogenic factors include environmental pollution, deforestation, irrigation, and clearing. In case of pollution of the land or excessive expansion of the irrigation facilities, the trees will lack nutrients to grow.