First, ancient poetry
1, Guanshan Wan Li Expeditionary Force, looked at Guanshan with tears. There is a moon in Qinghai garrison, but there is no spring in yellow sand. Looking at the sky from the high threshold, Wuwei, and guarding the micro-gold from the poor. Nine cities are far away, and Guan Shanxue flies overnight; Old Jia of Persia crossed quicksand and listened to camel bells at night to find his way on credit. Jade river picks bluestone, and Dongguo yisangma picks it.
2. The desert sand is like snow, and the Yanshan moon is like a hook. Why do you have to be a golden brain, go quickly and step on the clear autumn; Border soldiers return to spring, and Taiwan Province is alone. During the day, the ground comes out and the Yellow River comes from the outside. The sand is like waves, and the wind is suspicious. If you want to go to Yin Guan, Yin won't open; The desert is empty of dust, and the new autumn grass is still fat. Pomegranate is red and grapes are purple, and I hope to return to my hometown in the distance.
Second, the desert
1, desert, mainly refers to the barren area where the ground is completely covered with sand, plants are very scarce, rain is scarce and the air is dry. Desert is also a "sand curtain", an area with drought and water shortage and scarce plants. Desert areas are mostly beaches or sand dunes, and rocks often appear under the sand. Some deserts are salt flats without any vegetation.
2. Deserts are generally aeolian landforms. There are sometimes valuable mineral deposits in the desert, and many oil reserves have been discovered in modern times. There are few residents in the desert, and resource development is relatively easy. The desert climate is dry and it is also a paradise for archaeologists. Many human cultural relics and earlier fossils can be found.
Third, the reason
1. Over-reclamation: From 1958 to 1962, agriculture was widely developed. Due to severe wind erosion, the initial yield of 1 ~ 2 years can still be maintained at 20 or 30 kilograms after reclamation in desert areas, and it is difficult to recover even seeds in the future, so we have to abandon farming.
2. Overgrazing: Due to overgrazing by local herdsmen, the grassland yield is insufficient, so many high-quality grass seeds are eaten before they grow or mature. In addition, goats, which account for more than half of the total livestock, move quickly and are good at peeling the stems of desert shrubs, planing grass roots and trampling, which makes the grassland yield less and less, forming desertification land and causing a vicious circle.
3. Unreasonable firewood harvesting: Taking Yike Zhao Meng as an example, it is estimated that a family of five will need to burn more than 700 kilograms of firewood every year. If Artemisia is harvested, each household needs 5000 kilograms, which is equivalent to most or all of Artemisia ordosica produced by fixed and semi-fixed sand dunes over 3 hectares.