Desertification deepens poverty and enlarges regional disparity. According to the survey, the country's rural population of 1 / 4
In the desertified areas, the average agricultural output value of people is only 34.2% of the national average, which is in the East
1 / 5 of the area. In the desertification area, the degree of poverty is increasing and the development gap is widening
The slogan of survival is sand control. Desert
desertification is the product of arid climate. There were deserts on earth as early as human beings appeared. However, no boundaries and between what impassable desolate desert and rich grassland. With water, the desert can grow luxuriant plants, become the oasis of vitality; and if the green space without water and plants, it can quickly degenerate into a piece of sand. While people in order to get more food, no matter how the climate and land
conditions, land reclamation, over grazing freely; in order to solve the problem of fuel, regardless of the
consequences, wanton felling of grass. In arid and semi-arid regions was dry and windy, now the land ravaged, vegetation destruction, less precipitation, more and more wind, strong wind erosion of soil, sand dune development more and more slowly. This makes it possible for arable land to become desertified land that is not suitable for grazing and farming.
Land desertification is a sign of environmental degradation and a positive feedback process of environmental instability. If the basic measures are not taken, the process of wind erosion and desertification will not stop automatically, but will aggravate the development. For example, the land desertification area has reached 744 thousand and 600 hectares in the central region of Ningxia. It's growing very fast. In the past 22 years, the area of land desertification has increased from 20% to 50 - 60%. The problem is serious.
\environment, because of excessive human activities damage the fragile ecological balance, make the desert like landscape with aeolian activities as the main feature of the original non desert areas, resulting in land degradation process degradation. Desertification is an important ecological environment problem in the world, and it is also a prominent geological problem. The serious problem is the \
Land desertification is also a problem in china.
The land desertification in the Chinese, which has desertification of the land of 176 thousand square kilometers, the potential desertification risk of land of 158 thousand square kilometers, in the humid areas of wind sandy land of 19 thousand square kilometers. The population affected by desertification is more than 5000 people, and nearly 4 million hectares of dry farmland and 5 million
hectares of grassland are affected. The area of desertified land in China has increased from 13.7 square kilometers to 176 thousand square kilometers. Therefore, the situation of China's erosion of land resources is also grim.
Desertification
1. Introduction
Desertification refers to the natural disasters caused by the land covered by plants into barren land. The desert here refers to the fact that the land is not suitable for plants to grow or develop agriculture, rather than because of the desert climate caused by the drying of the region itself. However, no plant growing land can cause dry climate because of the lack of Evapotranspiration to distribute water.
The phenomenon of desertification may be natural. Desertification as a natural phenomenon is due to the movement of the dry zone of the earth, resulting in climate change leading to desertification in some areas. However, today the world desertification reasons, most attributed to anthropogenic causes; rapid population growth, the land in excessive farming and livestock, resulting in land dry thirsty for farming.
The Mesopotamia (now Iraq) region in the Middle East is one of the earliest regions to develop agriculture in the world, thus developing into one of the earliest birthplaces of civilization in the world. The soil of Mesopotamia was very
rich, but because of excessive agricultural activities, people ignore the long-term land dry thirsty, more developed river upstream and deforestation, the upper land which can not absorb rainfall, rain stretch into the river caused by soil erosion and flood.
According to the State Forestry Bureau Chinese in June 17, 2006 announced that Chinese desertified land reached 1 million 739 thousand and 700 square kilometers, accounting for 18% of the land area of more than 30, the impact of national level administrative region (province, autonomous regions and municipalities directly under the central government).
Dry land (defined as areas with low rainfall and rainfall usually caused by small rainfall, instability, short duration, and high intensity) covers 40% of the world's land area, supporting the world's 1/5 population. These dry land desertification is due to vegetation and water availability, reduce crop yield reduction and soil erosion caused by land degradation, it is due to population growth, increased demand for human or political and economic pressure (for example, the need of economic crops to increase foreign exchange) over land use caused by natural drought, usually start or worse. At present, the rate of desertification is 60 thousand square kilometers per year or 0.1% of the total dry land area per year. This is a potential threat to 70% of dry land (25% of the global land area).
In the arid and sub arid areas (including the part of sub
humid region), a loose sandy surface in the arid and windy conditions, due to unreasonable human activities, so that the original non sandy desert area, the degradation process is similar to the desert landscape, undulating dunes sand activities as the main indicator of the environment. The land area affected by desertification is about 38000000 square kilometers. At present, there are about 6 million hectares of land desertification in the world every year. Desertification has a wide range of concerns, which has attracted worldwide attention. Natural factors of desertification, drought is mainly surface loose sandy sediments and strong winds blowing; human factors include excessive reclamation, overgrazing, excessive firewood firewood and irrational utilization of water resources. Desertification is a phenomenon of environmental degradation. It is a process that gradually leads to the decline of biological productivity, including three stages of occurrence, development and formation. The stage (early stage) is the potential of desertification, there are only basic conditions of desertification, such as dry climate, vegetation has been destroyed, and the formation of a small area of loose sand; development stage, ground vegetation has been destroyed, surface roughening, wind erosion occurs, the speckled sand and low Nabkhas. With the sand activities intensified, further sand dunes or blowing the nabkha;
In the formation stage, the surface of the land is widely distributed with the mobile sand dune or the shrub sand, which accounts for more than 50% of the land area. The harm of desertification is the destruction of land resources, reducing the availability of agricultural land area, land
自然灾害对人类活动的影响(The influence of natural disasters on human activities)
