Thursday, December 29, 2011

Soil Formation and Erosion

Soil formation
Soil is the uppermost, fertile layer of the earth. It is one of the natural resources present on the earth. It is formed by the physical, substance, genetic and organic changes which go on taking place constantly in the layers of the earth, by the external forces like water, wind, glacier, ocean waves, etc. the weathered rock can be of different size. The numbers factors contribute a lot in the formation of the soil.
Climate has a significant role in influencing the decomposition of the different rocks to a great extent. The quality and amount of moisture and dryness in the soil depends upon the climate. The soil forming processes take place differently in varying climatic conditions. Its' took place more rapidly in the summer and rainy season. The classification and patterns of soils also depend on the climate.
The nature of weathered particles is responsible for the formation of soil. The particles may be obtained from the weathering of rocks or depositing of material by river, winds, glaciers, etc. The physical and chemical compositions of soil particles determine the relative proportions of different minerals in the layers.
The topography of a region affects the formation of soil. Steep slopes in the mountainous areas have the thin soil layers. It's due to the erosion and the state of moisture in the different layers. In areas of bad drainage and rigid topography, soil is not well developed.
Time is an important factor of soils' formation. A rich and fertile soil is formed only when the weathered particles of rocks remain uninterrupted on the same place for a long time.
It is only the longevity of time that the action of physical, chemical and organic processes takes place. It leads to the formation of deep and well- developed layers of soil. If time is not sufficient, the soils will remain undeveloped and skinny.
Soil profile
Each type of soil has a well-developed vertical section called the soil profile. There are four distinct layers in the soil profile.
The top layer is the biological layer and consists of fine particles and natural matter from decayed plants and animals. It is about 1-2 inches thick. Living things carry on with their life activities in this layer. Therefore, it is called humus.
The second layer is the horizon A. This layer has bacteria, which helps in the recycling of different material, and has plant's roots, fungus, etc.
The next layer is called horizon B, which contains materials obtained from the top layer by the seepage of water from the surface. It has a few symptoms of life. Below the sub- soil, there are the layer rocks and pebbles, of partly weathered rocks. In some areas, it contains water, depending on the water table.
Causes of Soil Erosion
Deforestation is the major cause of soil erosion. In the natural conditions, the roots of the trees hold the soil particles together and save soil for erosion. However, when trees are cut down uncontrollably, running water cut the soil and become a cause of erosion. Nothing can check the speed of running water during the rainy season. It erodes soil ruthlessly.
Drizzle and light showers do not cause much damage to the soil, but heavy and torrential rains carry away the fine soil particles with them due to their great speed and erosive capacity.
Overgrazing, especially by cows, goats, camels and sheep in the desert and semi-desert areas are the causes of Soil erosion. Plants and vegetation, which conserve soil, are uprooted by these animals. It generally happens on the mountainous, arid and semi-arid regions. Water during the rainy season carries away the loose soil. Same actions are done by wind the desert areas, resulting in the soil erosion.
In the areas of steep slope like mountain and hilly areas, water is more affected, then any other agent of erosion.
Clayey soil an absorb water easily. Therefore, the soil erosion is much less in the areas of clayey and sandy soil. Land is a prime natural resource, but due to its excessive use; it has been degraded to a large extent throughout the world.
Soil erosion, mining activities, solid waste, land pollution, etc. has degraded land resources. It has become unfit to any other use.

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