Questions about geography

Rocky desertification is karst rocky desertification or petrochemical, which is similar to the desertification situation in northwest China and is one of the extreme forms of land degradation and evolution. There used to be a large area of carbonate rocks in Guangxi and Guizhou, but the original vegetation was destroyed due to continuous land reclamation. The barren soil layer formed after thousands of years was quickly eroded by wind and rain, and finally only stones that could not grow any plants were left on the surface. The rate of rocky desertification in western China is quite fast, in which the carbonate rocks in Guangxi account for 37.8% of the total land area, and the rocky desertification is increasing by 3%-6% every year. The rocky mountainous area not only forms a vicious circle of "poor people in poor mountains enter wasteland", but also is the most difficult "hard bone" for afforestation because of its thin soil and easy drought.

Rocky desertification refers to the phenomenon of land degradation in tropical and subtropical humid and semi-humid climate. Karst and its development are disturbed by human activities, which destroys the surface vegetation and causes serious soil loss, and large areas of bare karst or gravel accumulation. This is an extreme form of land degradation in karst areas.

Rocky desertification is the abbreviation of "rocky desertification". Rocky desertification is an evolutionary process in which the contradiction between man and land is prominent, vegetation is destroyed, soil erosion, land productivity is reduced or lost, and rocks with similar desert landscape are gradually exposed under the fragile ecological environment of karst. From the cause of formation, the main factor leading to rocky desertification is human activities. For a long time, natural vegetation has been destroyed continuously, and a large area of steep slope has been reclaimed, resulting in bare surface. In addition, the karst mountain area has thin soil layer, shallow exposed bedrock and strong rainstorm scouring ability. After a lot of soil erosion, rocks gradually emerged, showing the phenomenon of "rocky desertification", and with the passage of time, the degree and area of "rocky desertification" are also deepening and developing. The most direct consequence of rocky desertification development is the loss of land resources. Due to the lack of vegetation and water conservation in rocky desertification areas, it is often accompanied by serious drinking water difficulties for people and animals. The phenomenon of "rocky desertification" after the continuous loss of water and soil resources not only worsens the agricultural production conditions and ecological environment, but also makes people lose their basic living conditions. Many places have to consider "ecological migration", such as Mashan area in Guizhou Province, which is a typical example. According to investigation and statistics, there are about 450,000 people who need to move due to ecological deterioration in karst rocky desertification mountainous areas of Guizhou Province, and measures are being taken to gradually move.

The area of light rocky desertification in Guizhou Province is 35,920 square kilometers, accounting for 20.39% of the national territory. Among them, the area of light rocky desertification is 22733 square kilometers, the area of moderate rocky desertification is 105 18 square kilometers, and the area of severe rocky desertification is 2669 square kilometers. In addition, there are 437 14 square kilometers of land with potential rocky desertification trend. Judging from the distribution of rocky desertification in county-level administrative units, there are obvious rocky desertification phenomena in all counties (cities) except Chishui, Rongjiang, Congjiang, Leishan and Jianhe. In terms of spatial distribution, rocky desertification land is mostly distributed in the south and west of karst development, with Liupanshui, Southwest Guizhou, Qiannan, Anshun and Bijie having the largest area, showing the characteristics that the south is more important than the north and the west is more important than the east. Divided by county-level administrative units, rocky desertification area; There are 9 counties that account for more than 40% of the land area, less than 10% in 17 counties, and the rest are between10% and 40%. Among the 50 key poverty alleviation and development counties in Guizhou, 30 counties have rocky desertification areas accounting for more than 20% of the country's land area, and the places with serious rocky desertification are the poorest places in Guizhou.

By the end of 2005, the total area of rocky desertification land in China was 654.38+296,000 square kilometers, accounting for 28.7% of the karst area.