degradation ability of plant breeding, to reduce the amount of land containing animal decreased crop yield per unit area decreased. Desertification has caused serious losses to agriculture, animal husbandry and people's living and property in many countries and regions.
Desertification is a major threat to the development of world agriculture. Desertification is a phenomenon of environmental degradation. It reduces the capacity of land breeding, reduces the productivity of agriculture and livestock production, reduces the amount of arable land and pasture area. Due to the desertification caused by soil erosion, poor land, has caused many countries suffered successive famine. Total land affected by desertification reaches 38 million sq km. Land lost because of
desertification, each year up to 5~7 square kilometers, almost every minute there are 11 hectares of land was desertification. If desertification continue and not effectively suppressed, at the end of this century, is expected to reach the current loss of cultivated land will be cultivated in 1/3, this is the kind of danger signal! Is a serious land desertification in China, desert and desertification land from 66 in 1949 to 70 thousand square kilometers to expand? 130 square kilometers in 1985, accounting for about 13 of the total land area, 6%. Desertified land also grows at a rate of 60 square kilometers per year. The formation of land desertification in China, in addition to natural factors of dune intrusion caused by force, due to excessive farming, overgrazing, deforestation, industrial transportation construction and destruction of vegetation caused by man-made
desertification phenomenon is more common. There is a set of statistical figures illustrate the problem, Chen I trapped cause of desertification land: deforestation accounts for 32? 4%? 4%, accounting for 29 of the excessive discharge? Land use accounted for 23 over? 3% improper water use accounted for 6%, accounted for 5%, 5 mobile dune? City Industrial and mining construction accounted for 0.8%. From these statistics, we can see that the vast majority (95%) of land desertification in China is caused by human factors. Therefore, to protect and make good use of land, a sand fixing grass, creating wind sarin, the comprehensive development of forestry and animal husbandry, water conservancy and other governance? Will give full play to the group effect planting sand soil to retreat. Soil is the mother of plants and the material base for the prosperity of green homeland. Protection and utilization of land, that is, to protect the green home, to protect the human themselves.
Desertification means the living things on the land. Its productivity decline or even lose, and the main reason is mainly from human destruction of the natural environment. One of the most obvious places of desertification is the hare on the south side of the Sahara desert. In the northern part of the country, sheep and camels are raised in nomadic or grazing ways, and the whole area is eaten up, resulting in a barren patch of land. And the more moist broadleaf south, due to excessive livestock breeding, coupled with the original heart but little arable land, no tillage continuously, the whole area has gradually become gally.
Coupled with the lack of water, people began to dig wells, while the crowd gathered by water, keeping livestock will rise again, accelerate the deterioration of the environment, contributing to desertification, this vicious spiral, so that the common people's life in the area had a very poor. The Sahara Desert no rainy season, so it won't rain, but as long as there is any a little redundant moisture, sleeping in the plants under the will to sprout, but soon, and excessive grazing livestock eat... So the sandy soil is still growing in silence...
.2 harm. The land desertification in China is one of the most serious environmental problems, the deterioration of the ecological environment, destroy the living conditions, increasing the occurrence of natural disasters, restricting economic development, enhance the level of poverty, seriously affect social stability, to China's national economic and social development has caused great harm. According to the calculation, the direct economic loss caused by land desertification is 54 billion yuan per year, which is equivalent to 3 times of the annual fiscal revenue of the five northwest provinces (regions),
In the year due to wind erosion loss of soil organic matter and nitrogen, phosphorus and potassium reached 5590 million tons, equivalent to 2.7 million tons of fertilizer, the hazards of sand storms, the less per year raise 5000 million, the annual grain output of 30 million tons, the country has more than 2.4 villages and towns often affected by sand hazards, some even become cause of ethnic conflicts,
an important factor affecting social stability, but also the threat of desertification, city transportation, water conservancy facilities and industrial and mining
enterprises. At present there are more than 1300 km railway, 30 thousand km road, thousands of reservoirs and more than 50 thousand km long in perennial wind damage. Every year, 16 tons of sediment are imported from the Yellow River, and 12 tons of them come from sandy areas. Source: \2009 sixth Wang Liming Liu Botong 2 / 1 feeds the China Journal net. Zhu Zhenda's concept of land desertification in China: Causes and prevention.
自然灾害对人类活动的影响(The influence of natural disasters on human activities)
