Where does desertification occur?
One of the most rapid processes of transformation of fertile soils into sandy rock is desertification. With this process, all vegetation disappears due to the complete destruction of the humus layer in the soil. This leads to the degradation of the landscape and the reduction of areas suitable for harvest. Soil desertification is caused by various factors. They can be natural, but often it is the result of human activity.
Desertification is not the formation of a desert ecosystem, which is a natural process, but an overly rapid change in the state of the soil. Usually places where desertification occurs have a dry climate. Thus, the most vulnerable zone is considered the central part of Africa. This is a transitional zone between the Sahara desert and savanna, with a changeable and hot climate.
Causes of Desertification
- Water deficiency. The lack of the required amount of groundwater to ensure the norms of water balance for various types of vegetation and crops.
- Prolonged drought.Caused by changes in climate, drought affects the ecosystem as a whole. The process of desertification is then accelerated.
- Climatic aridization. Excessive decrease in air humidity due to increased temperature and low precipitation.
- Increase livestock. This leads to excessive thinning of pasture vegetation. Because of this, the amount of moisture in the soil is significantly reduced. Especially the choice of pasture near water sources, for example, wells, leads to the drying of the soil. Previously practiced method of nomadic pastures has lost relevance for many pastoralists, and therefore pastures are static in one place, which makes it impossible to restore vegetation.
- Deforestation. With a sharp deforestation, soil erosion may begin, especially on the slopes of mountains and near-plain plains. Formed ravines. Due to a decrease in forest plantations, the moisture balance changes, since there is no gradual thawing of snow and preservation of moisture in the soil.
- Salt accumulation. Increases in salt levels in the soil can occur for a number of reasons. The first is the transfer of salts from the lower layers of the soil by groundwater to the upper layers.Between the groundwater, saturated salts and minerals, there are permeable soils - sand, gravel deposits, etc. This process may also have a reverse direction - from the upper layers salt deposits will penetrate with the groundwater into the deeper layers of soil. This is typical of lowlands and low plains.
- Windy climate. Because of the wind that carries rocks, deeper layers of soil open up. Also, salt accumulation can be caused by man-made activities. Waste mines, factories and steel mills usually accumulate in ravines and lowlands. From there, with groundwater, chemicals enter the ground.
- Low water table. The main reason for this is the natural drainage of water bodies. This process is associated with a reduced amount of precipitation, which cannot replenish and normalize the desired water balance. Also, the groundwater level may decrease due to artificially created drainage.
- Mistakes in farming. Excessive drainage of shallow reservoirs for irrigating land and maintaining fisheries leads to desertification.The water balance of the region is disturbed, and this leads either to the drainage of the soil or to an increase in the level of salts. The cultivation of excessively moisture-loving crops also contributes to the drying of soil. On their irrigation will need to spend much more water. An increasing amount of the world's population requires greater yields. Because of this, many farmers ignore the mandatory timing of land deposits, in which the chernozem layer is restored, and the soil becomes again fertile. The constant exploitation of fertile soils leads to soil depletion and erosion.
Ways to Eliminate Desertification
Ways to prevent and influence factors of desertification are different. Since one of the main causes of soil drying is the accumulation of salt in the soil and the movement of soils, reclamation of pastures helps a lot. In a zone with a dry climate, with low rainfall, grass and shrubs are planted. Pre-soil is treated with fertilizer. In the case of a more desert climate, oasis irrigation is also applied.
Sometimes a local government may prohibit the use of certain zones of land for the period of their full natural restoration. Desertification control is also conducted after mining operations.After the completion of these works is carried out so-called. recultivation. This is the restoration of vegetation by artificial means.
In agriculture, changing the direction of plowing. Large areas are left, and instead, fields located near hills are subject to so-called contour processing. Agromelioration also plays a major role here. This process consists of steppe afforestation, the formation of soil and forest protection plants.