Land Resources: Environmental sciences Notes, MCQ, Books, PDF
EVS Notes Unit I Multidisciplinary nature, Natural Resources, Forest resources, Water resources, Mineral resources, Food resources, Energy resources, Land resources, Role of an individual Unit II Introduction structure-function, Forest eco-system; Grassland ecosystem; Desert ecosystem; Aquatic ecosystems Unit III Air pollution, Water pollution, Soil pollution
Land as a Resource
The land area constitutes about 1/5 of the earth’s surface. To meet the challenging demand for food, fiber, and fuel for the human population, fodder for animals, and industrial raw material for agro-based industries, efficient management of land resources will play a critical role. Soil, water, vegetation, and climate are basic natural resources for agricultural growth and development.
Due to the increasing population, the demand for arable land for producing food, fiber, and fuel wood is also increasing. Hence there is more and more pressure on the limited land resources which are getting degraded due to over-exploitation. Nearly 56% of the total geographical area of the country is suffering due to land resource degradation. Out of 17 million hectares of canal irrigated area, 3.4 million hectares are suffering from water logging and salinity. Soil erosion, water logging, salinization, and contamination of the soil with industrial wastes like fly-ash, press mud, or heavy metals all-cause degradation of land.
Soil erosion refers to the loss or removal of the superficial layer of soil due to the action of wind, water, and human factors. In other words, it can be defined as the movement of soil components, especially surface litter and topsoil from one place to another. It has been estimated that more than 5000 million tonnes of topsoil is being eroded annually and 30% of the total eroded mass is getting loosed to the sea. It results in the loss of fertility. It basically is of two types, viz. geologic erosion, and accelerated erosion. Various factors which affect soil erosions include
soil type, vegetation cover, the slope of the ground, soil mismanagement, and intensity and amount of rainfall. The wind is also responsible for land erosion through saltation, suspension and surface creep.
In order to prevent soil erosion and conserve the soil, the following conservation practices are employed,
Conservational till farming, Contour farming, and Terracing
Strip cropping and alley cropping
Windbreaks or shelterbelts
It refers to the accumulation of soluble salts in the soil. The concentration of soluble salts increases due to poor drainage facilities. In dryland areas, salt concentration increases where poor drainage is accompanied by high temperature. A high concentration of salts affects the process of water absorption and hence affects productivity.
Excessive utilization of irrigation may disturb the water balance which can lead to water logging due to the rise of the water table . Anaerobic conditions due to poor availability of oxygen in waterlogged soils may affect the respiration process in plants which will ultimately affect the productivity of water-logged soil.
Desertification is a process whereby the productive potential of arid or semiarid lands falls by ten percent or more. Desertification is characterized by devegetation and depletion of groundwater, salinization, and severe soil erosion.
Causes of Desertification
• Mining and quarrying
Shifting cultivation is a practice of slash and burn agriculture adopted by tribal communities and is the main cause of soil degradation, particularly in tropical and sub-tropical regions. Shifting cultivation which is also popularly known as ‘Jhum Cultivation’ has led to the destruction of forests in hilly areas. It is responsible for soil erosion and other problems related to land degradation in mountainous areas.
Man Induced Landslides
The human race has exploited land resources for its own comfort by constructing roads, railway tracks, canals for irrigation, hydroelectric projects, large dams and reservoirs, and mining in hilly areas. Moreover productive lands under crop production are decreasing because of development activities. These factors are affecting the stability of hill slopes and damaging the protective vegetation cover. These activities are also responsible to upset the balance of nature and making such areas prone to landslides.
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