Land Desertification Soil and Water Erosion Secondary Salinization Causes of Hazardous Measures

①Basic Condition - Arid Climate with little rainfall

Arid climate, poor surface water, underdeveloped rivers, and weak water flow, while physical weathering and wind force are significant, thus forming a large area of the Gobi and deserts;

②Material Conditions -- The ground is loose and sandy

Due to the arid climate, sparse vegetation and poor soil development, the flat land is mostly loose and sandy sediments;

③ Dynamic conditions - the number of days of high winds is high and concentrated

The number of windy days is high and concentrated in the dry season of winter and spring, thus creating favorable conditions for wind and sand activities.

④ Climate anomaly can make the fragile ecological environment imbalance, is to lead to desertification desertification process.

It belongs to the temperate continental climate, with an important feature is the high variability of temperature and precipitation. The variation of rainfall plays a crucial role in the occurrence and development of desertification. A rainy year is conducive to the suppression of wind and sand activities; a rainy year exacerbates the process of desertification.

Anthropogenic causes of desertification:

1) Pressure on the ecological environment from population explosion

2) Excessive use and irrational utilization of land and water resources due to improper human activities.

2. The main manifestations of anthropogenic factors of desertification in Northwest China (Fig. 2, 5)

Anthropogenic Factors

Causes of Destruction and Typical Areas

Main Hazards

Excessive Woodcutting

①Woodcutting of natural vegetation in areas of energy scarcity as a major means of solving the fuel problem (e.g., the sandy areas of Ordos, the eastern part of Inner Mongolia's (Kulunqi, eastern Inner Mongolia, etc.) ② some farmers and herdsmen in order to increase income, unplanned, uncontrolled in the grassland areas to dig herbs, hairy vegetables, etc.

Sand fixation, to prevent the sand front and inhibit the surface of the sand of the vegetation was destroyed

Overgrazing

In order to seek short-term economic benefits, herders as much as possible to graze their livestock. Semi-arid steppe pastures, arid oasis edges

Accelerating the process of steppe degradation and desertification

Over-cultivation

Engaging in agricultural production in arid and semi-arid sandy soil areas, especially on the edge of sandy zones, and especially in sandy soil areas that lack protection from shelter forests

Making sandy land develop in a continuous manner

Desertification phenomenon --Secondary salinization

(1) Oasis: in desert areas irrigated by water.

(2) secondary salinization formation:

① due to backward farming techniques, improper irrigation measures

② arid climate conditions evaporation is vigorous, salt is very easy to gather on the surface and formed.