Chapter Notes and Summary
• Land :
Land is an important natural resource which covers only 30 percent of earth’s surface.
Land provides most of human needs. Its use depends on physical factors such as topography, soil, climate, mineral and availability of water and human factors.
Due to excessive use of land for agricultural and constructional activities, major problem of land degradation, landslides, soil erosion, etc. arises.
To conserve land, we must promote afforestation, check overgrazing and regulate use of chemical pesticides and fertilizers.
• Soil :
upper layer of land’s surface is called soil. This is further divided into top soil, sub-soil, weathered rocks and bed rocks which are inclusively known as soil profile.
Soil formation depends on nature of parent rock, climate, relief features, flora, fauna, microorganisms and time.
Deforestation, overgrazing, overuse of chemical fertilisers and pesticides, rain wash, landslides and floods leads to soil degradation.
Conservation of soil can be done by mulching, contour barriers, constructing rock dam, terrace farming, intercropping, contour ploughing and making shelter belts.
• Water :
Three-fourth of earth surface is covered with water, out of which only 2.7 per cent water is fresh water, but only 1% of fresh water is available for human use.
excessive use of water leads to shortage in supply of fresh water either due to drying up of water sources or due to water pollution.
Discharge of untreated sewage, agricultural chemicals and industrial effluents in water bodies causes water pollution.
Water conservation can be done by afforestation, adopting effective techniques for irrigation and promoting rainwater harvesting.
• Natural Vegetation and Wildlife :
Natural vegetation and wildlife exist only in biosphere and they are interrelated and interdependent on each other for their survival. This system is called ecosystem.
Natural Vegetation and Wildlife both are valuable resources. They are not only useful for us, but they also help in maintaining balance in nature.
Major vegetations of ecosystems are Forests, Grasslands, Scrubs and Tundra.
Due to deforestation, soil erosion, constructional activities, forest fires, Tsunami, landslides and poaching, many species of vegetation and wildlife have become extinct and many others are on verge of extinction.
We can conserve Natural vegetation and wildlife by making national parks, wildlife sanctuaries and biosphere reserves.