Geography: Earth's Interior and Its Material: Soil Conservation Practices

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Soil Conservation

Soil is one of the most important natural resources, which sustains different lives directly or indirectly. The process of soil erosion not only destroys this wonderful gift of nature, but it also creates new problems such as floods, damage to roads, rail bridges, hydroelectric projects, water supply and pumping stations.

Image of soil conservation

Image of Soil Conservation

Image of soil conservation

Soil conservation constitutes those methods which prevent soil from being removed. The methods to control different types of soil erosion in different parts of the world are:

Protection of Forests: Indiscriminate felling of trees in the forests has been one of the major causes of soil erosion. Since roots of the trees hold the soil material together, it is desirable to protect these trees from such felling. This has led governments to declare forests as reserved in which felling of trees has been banned.

Afforestation: Planting of trees along river courses, waste lands and mountainous slopes is another method of soil conservation. Afforestation is also effective in controlling wind erosion along the desert regions. In India, large scale planting of trees is being carried out in Rajasthan, Haryana, Gujrat and Punjab to control the extension of Thar Desert.

Flood Control: During rainy season, the amount of water in rivers, increases exceedingly which in turn increases soil erosion. Dams are being constructed to control floods and consequently the soil erosion.

Planned Grazing: Over grazing on hill slopes has results in the loosening and washing away of soils in these areas. If grazing is carried out in a planned way it will reduce soil erosion by protecting vegetation cover in these areas which are comparatively more prone to soil erosion.

Terracing: Terracing refers to the construction of terraces across the slope in a mountainous region. This helps in controlling soil erosion and using water resources of these areas economically and effectively for growing different crops on these terraces.

Contour Ploughing: This method of soil conservation is most suited to areas having rolling landscape. Ploughing and tilling of land along the contour levels in order to cause furrows to run across the land slope reduces the rate of soil erosion.

Crop Rotation: Crop rotation refers to a systematic succession of different crops cultivated in a given piece of land in order to avoid exhaustion of the soil. Thus, rotation of crops is applied to conserve the fertility of soil from over cultivation of growing continuous crops from where population pressure is more on limited agricultural lands.

Reclamation of Lands: Soil erosion is also being controlled by levelling lands gullied down by water channels and converted into waste lands or ravines. This method of soil conservation is most suited in river basins and hilly terrains.

In brief, it can be said that

  • Earth is a spherical body. The direct observations into its interior are limited to a depth of a few kilometres. Temperature, pressure and density increase from the earth’s surface to its center. Earth’s interior is divided into three concentric layers of crust, mantle and core.

  • Crust is the thinnest and outermost layer; mantle is the middle one whereas core is the innermost and the densest layer of the earth. The material of the crust is composed of rocks. Rock is composed of one or more minerals. Minerals have a definite chemical composition. On the basis of their mode of formation, rocks are classified into three types - igneous, sedimentary and metamorphic.

  • Igneous rocks are formed by the solidification of molten lava or magma. Granite, basalt and gabbro are examples of igneous rocks. Molten material solidified beneath the earth’s surface to form intrusive and above the earth surface to form extrusive igneous rocks. Sedimentary rocks are formed by the consolidation of sediments.

  • These are layered and may contain fossils. Metamorphic rocks are formed by the effect of heat or pressure on any pre-existing rock. Rocks provide precious metals and stones, building material and fuel etc. for our use.

  • The rocks undergo various types of changes in their own location under the process of weathering. The rocks become weak due to the impact of the weather elements - temperature, moisture, frost etc. They develop cracks and disintegrate into small boulders, pebbles or fine fragments. Mechanical weathering is more pronounced in areas of hot and dry or very cold climates.

  • Rock minerals undergo chemical changes due to the effect of water and gases as a result of oxidation, carbonation, hydration and solution. Chemical weathering is more important in areas of warm and humid climates. Plants, animals, insects and men are the agents of biotic weathering and they contribute to both mechanical and chemical weathering.

  • Soil is a thin layer of loose inorganic and decayed organic matter covering the earth’s surface. Different factors such as parent materials, climate, plants and animal organism, water and time along with processes such as mechanical, chemical and biological are responsible in making this valuable resource. Mature soils develop a profile which constitutes four horizons, each having different characteristics.

  • Soil erosion is a natural process of destruction and removal of soil material from its place. Running water, winds, sea waves and glaciers are the most active agents of erosion. Erosion of soils takes place in four ways viz., wind erosion, sheet erosion, rill erosion and gully erosion.

  • Removal of soil cover depends on velocity and speed of water, nature of slope, texture and structure of soils, frequency of dust storms and nature of precipitation. Methods to prevent soils from being eroded constitute soil conservation. These methods are protection of forests, afforestation, contour ploughing, terrace and strip farming, bunding, flood control, etc.

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