• Land, soil, water are the resources which belong to abiotic resources and are the most important resources.
• Whereas natural vegetation and wildlife resources come under biotic resources.
• Land:
(i) Land is among the most important natural resources. Land covers about 30% of the total area of the earth’s surface.
(ii) Ninety percent of the world population occupies only 30% of the land area. The remaining 70% of land is either sparsely populated or uninhabited.
(iii) Land is unevenly inhabited due to various factors of land and climate, water fertility of soil, etc.
(iv) Normally the sparsely populated or uninhabited areas are because of rugged topography, steep slopes of the mountains, low -lying areas susceptible to water logging, deserted areas and thickly forested areas.
(v) The densely populated areas of the world have plains, river valleys which have suitable land for agriculture.
• Land use:
(i) Land use refers to the use of land use for different purpose such as agriculture, forestry, mining, building houses, roads and setting up of industries.
(ii) Factors affecting land use are of two kinds- (i) Physical factors and (ii) Human factors.
(iii) Physical factors include topography, soil, climate and availability of water. Human factors include population and technology.
(iv) On the basis of ownership, land can be classified as private and community land.
(v) Private land is owned by an individual or family members and is used for personal purposes like house is a private land.
(vi) Community land is owned by the community for common uses and can be used by anyone in the society like collection of fodder, fruits, nuts or medical herbs. These community lands are also called common property resources.
(vii) The demand for land by the people is growing but the availability of land is limited.
(viii) The vast changes in the land use pattern shows the cultural changes in our society.
(ix) Land degradation, landslides, soil erosion, desertification are the major threats to the environment because of the expansion of agriculture and construction activities.
• Conservation of Land Resources:
(i) Growing population and their ever-growing demand has led to a large scale destruction of forest cover and arable land and has created a fear of losing these natural resources.
(ii) The present rate of degradation of land must be checked.
(iii) The common methods used to conserve land resources are afforestation, land reclamation, regulated use of chemical pesticides and fertilisers and checks on overgrazing.
• Soil:
(i) Soil is the thin layer of grainy substance covering the surface of the earth.
(ii) Soil is made up of organic matter, minerals and weathered rocks found on earth.
(iii) Soil profile refers to the layered structure which spreads from the parent rocks to the top soil surface.
(iv) The four layers of soil profile are: 1st layer-Top soil with humus and vegetation, 2nd layer-Sub soil with sand, silt and clay, 3rd layer-weathered rock material, 4th layer- Parent rock.
• Factors of Soil Formation:
(i) The major factors of soil formation are the nature of the parent rock and climatic factors.
(ii) The other factors of soil formation are the topography, role of organic material and time taken for composition of soil formation.
(iii) Parent rock determines the colour, texture, chemical properties, minerals, content and permeability of the soil.
(iv) Relief determines the altitude and slope and accumulation of soil.
(v) Flora, fauna and micro-organism affect the rate of humus formation in soil.
(vi) Climate determines temperature and rainfall which influence the rate of weathering and humus in process of soil formation.
(vii) Time determines the sickness of soil profile. It takes hundreds of years to make just on centimeter of soil.
• Degradation of Soil and Conservation Measures:
(i) The major threats to soil erosion and depletion.
(ii) Human beings and natural factors are responsible for degredation of soils.
(iii) Deforestation, overgrazing, overuse of chemical fertilisers or pesticides, rain water,
landslides and floods are the factors which leads to soil degradation.
(iv) Soil conservation refers to the protection, efficient use of soil and preservation of soil resources.
(v) Mulching is the method in which the bare ground between plants is covered with a layer of organic matter like straw. It helps to retain soil moisture.
(vi) Contour barriers is the method in which stones, grass, soil are used to build barriers
along contours. Trenches are made in front of them to collect water.
(vii) In Terrace farming, broad flat steps or terraces are made on the steep slopes, so that flat surfaces are available to grow crops. It reduces the surface runoff and soil erosion.
(viii) In intercropping, different crops are grown in alternate rows and are sown at different times to protect the soil from rain wash.
(ix) Contour ploughing is the process of ploughing parallel to the contours of a hill slope to form a natural barrier to stop water from flowing down the slope.
