- Natural vegetation and wildlife resources are biotic resources.
- Land, water and soil which are abiotic resources are the most important resources.
- Both biotic and abiotic resources are exhaustible in nature.
Land:
- is the part of the earth’s surface that is not covered by water
- Land is one of the most important natural resources and covers about 30% of the total area of the earth’s surface.
- 70% of land is either sparsely populated or uninhabited and the rest 30% is occupied by 90% of the world population.
- Land is unevenly inhabited due to various factors of land and climate, availability of water and fertility of soil etc.
- Areas that are uninhabited or have very few or no population are areas that
- have rugged terrain
- have steep slopes
- are low-lying areas that are susceptible to water logging
- are desert areas or thick forests
- The densely populated areas of the world are plains and river valleys as they have suitable land for agriculture and moderate climatic conditions.
- The availability of rich and fertile land makes it suitable for living.
- Mineral richness, water resources, fertility of soil and good topographical conditions are important.
Land uses:
- The use of the land depends on various factors like topography, soil, climatic conditions, presence of mineral reserves and the availability of drinking water.
- Land use refers to the use of land for different purpose such as agriculture, forestry, mining, construction, roads and setting up of industries.
- Factors affecting land use are
- Physical factor
- Includes topography, soil, climate and availability of water. Human factors
- Human factor
- includes population and technology
- On the basis of ownership, land can be classified
- Private land
- is owned by an individual or family member and is used for personal purposes like house is a private land
- 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
- are also called common property resources
Conservation of Land Resources:
- The availability of land is limited but the demand for land by the people is growing.
- Due to the cultural changes in our society there are vast changes in the land use pattern.
- Extensive use of fertile land, without careful utilization, can lead to the barrenness of that land.
- The over exploitation of mineral resources can make the soil vulnerable to degradation.
- Due to the expansion of agriculture and construction activities, the major threats to the environment are
- Land degradation
- can be caused by
- deforestation
- cutting down trees and clearing forests to clear land for construction or other use
- overgrazing and excessive use of chemical fertilisers and pesticides
- rain wash and flood
- The washing action of rain as well as flow of water in floods transport soil from one place to another and are capable of erosion
- landslides
- is when rock, debris or loose earth move down a slope in a huge mass
- often takes place along with earthquakes, floods and volcanoes
- Soil erosion
- occurs when soil and rock particles are carried away by wind, water or ice and are deposited in another location
- Soil depletion which affects the quality and fertility of the soil, takes place when the nutrients in soil are removed and are not replaced.
- Desertification
- can be caused due to removal of natural vegetation and trees
- The common methods used to conserve land resources are
- afforestation
- Planting more trees can help restore the forest cover. This process is known as afforestation.
- land reclamation
- is another method of land conservation for farmers
- is the process of creating new land from ocean, riverbeds, or lake beds
- regulated use of chemical pesticides and fertilizers and checks on overgrazing
- The government can play an active role in preserving the soil and land by
- making rules related to soil and land conservation
- making the farmers educated regarding the negative aspects of over utilization of fertilizers and overgrazing
Soil:
- is the thin layer of coarse and rough substance covering the earth’s surface
- is made up of organic matter, minerals and weathered rocks
- is different in different geographic regions
- Soil profile refers to the layered structure which spreads from the parent rocks to the top soil surface.
- The four layers of soil profile are:
- 1st layer is the top soil with humus and vegetation
- 2nd layer is the sub soil with sand, silt and clay
- 3rd layer comprises of weathered rock material
- Rocks, as a result of the breakdown and decay due to changes in temperature, frost and actions of living organism, get weathered.
- It is a very slow process and is called weathering.
- During weathering, rock debris gets mixed with organic matter and minerals thus increasing the fertility of the soil.
- 4th layer is the parent rock
- The thickness of the soil profile is affected by the time taken for the soil to form.
- Older soil has a thicker soil profile compared to new soil.
- As steep slopes are more prone to soil erosion the layer of soil on them is generally thin whereas flat areas have a thick layer of soil as they retain the layers of soil for longer periods.
- The types of soil found in India include Alluvial, Black, Red, Laterite, Desert and Montane.
Factors of Soil Formation:
- Various factors affect the physical and chemical properties of soil.
- The major factors are the nature of the parent rock and the climate of that area.
- Parent rock
- determines the texture, color, chemical properties, minerals content and permeability of the soil
- Climatic conditions
- like temperature and rainfall
- determine the rate of weathering and the formation of humus
- The other factors are
- Relief
- determines the altitude and slope and accumulation of soil
- Flora and fauna
- affect the rate of humus (degraded organic material) formation in soil
- Humus increases the soil fertility.
- Micro-organism
- play a very important role in soil nutrient cycle and minerals balance
- help in the process of decomposition
- Time
- determines the thickness of soil profile
- Soil formation is the result of the mixture of all the geo-climatic factors available and it takes hundreds of years to make just one centimetre of soil.
Degradation of Soil and Conservation Measures
- Deforestation, overgrazing, overuse of chemical fertilizers or pesticides, rain water, landslides and floods are the factors which leads to soil degradation.
- Excessive use of fertilizers and high yield crop variety is also a cause of soil degradation and leads to loss of fertility of soil.
- Soil conservation refers to the protection, efficient use of soil and preservation of soil resources.
- Some methods to conserve soil quality are
- Mulching
- is the method in which the bare ground between plants is covered with a layer of organic matter like straw
- This helps to trap moisture in the soil and moderate soil temperature.
- Contour barriers
- is the method in which stones, grass and soil are used to build barriers along contours with trenches built in front of the barriers to collect water
- This prevents water to flow down the contours and wash away the soil.
- Rock dams
- are dams created from rocks that are arranged in a pile to slow down the flow of water and prevent the formation of gullies
- This reduce the soil erosion
- Terrace farming
- is where broad flat steps (terraces) are made on the steep slopes to grow crops
- It reduces the surface run-off and soil erosion.
- Intercropping
- is a cultivation method in which two or more crops are grown in the same field
- The crops are grown in proximity in alternate rows.
- is a widely practiced in China to reduce soil erosion due to rain wash
- To improve the fertility of soil, mixed farming and crop rotation can also be used.
- Contour ploughing
- is the method in which the land is ploughed parallel to the contours of a slope
- This creates a barrier that prevents water from flowing down the slope
- Shelter belts
- are the rows of trees planted to check the wind movements to protect soil cover
- is practiced in coastal and dry areas
Water:
- Water is vital renewable natural resources.
- Earth is called ‘water planet’ because three fourth of its surface is covered with water.
- The total volume of water on the earth remains constant as it keeps getting recycled from one form into another. Water evaporates from the oceans to transform into water vapour and falls back on the land in form of rains.
- Ocean water is salty and hence cannot be used for human consumption.
- Fresh water accounts for only 2.7% of the total water available out of which only 1% is available and fit for human use and is found as ground water, rivers and lakes etc.
- Water is used for agriculture, industries, generating electricity through reservoirs of dams etc.
- The major causes of water shortage are
- increasing population
- rising demands for food and cash crops
- increasing urbanization
- rising standards of living
Problem of Water Availability:
- There is water shortage in many regions of the world due to variation in rainfall and over-exploitation and contamination of water sources.
- Contamination of water can be due to
- release of untreated or semi-treated sewage
- Agricultural chemicals
- Industrial effluents
- Countries located in climatic zones are most susceptible to droughts and face great problems of water scarcity.
- Global warming and high pace of industrialization also lead to shortage of clean water.
Conservation of Water Resources:
- Water is a renewable resource but its overuse and pollution makes it necessary to conserve water.
- Sewage, agricultural chemicals and industrial waste also pollute the water with nitrates, metals and pesticides.
- Various steps can be taken to conserve water and prevent it from getting polluted.
- Growing more trees since forests slow the surface run-off and restore underground water.
- Using water harvesting method to save surface runoff.
- Regularly checking canals that are used for irrigation for any seepage or water.
- Collecting rain water and storing it for use in harvesting etc.
- Installing recycling plants to conserve water and stop wastage.
- Developing better irrigation facilities to conserve water.
- Ensuring that effluents are treated properly before being discharged into water bodies.
- Using methods like sprinklers and drip or trickle irrigation.
Natural Vegetation and Wildlife:
- Natural vegetation and wildlife are inter-related and interdependent on each other for survival and exist in the biosphere.
- This life supporting system is known as the ecosystem.
- Plants provide us with fruits and vegetables, timber, shelter, oxygen, protect soil, act as shelter belts and help in storage of underground water.
- Wildlife includes all undomesticated animals, birds, insects and aquatic life forms.
Distribution of Natural Vegetation:
- The growth of vegetation depends on temperature and moisture.
- The major types of vegetation of the world are
- Forests
- are associated with areas having abundant water supply
- have heavy rainfall and huge trees
- Grasslands
- are areas having short stunted trees and grasses
- grow in the regions of moderate rainfall
- The size of trees and their density reduces as the amount of moisture decreases.
- Thorny shrubs
- grow in dry areas of low rainfall
- have deep roots and leaves with thorny and waxy surface that helps reduce loss of moisture through transpiration
- Tundra vegetation
- found in cold Polar Regions
- comprise of mosses and lichens
- Depending upon when they shed their leaves, the types of forests are
- Evergreen
- do not shed their leaves all at the same time, hence they always remain green
- Deciduous
- shed their leaves in dry season to conserve loss of moisture through transpiration
- Mostly Evergreen and Deciduous forests, that are the rich source of timber and forest produce, are found in India.
- In Himalayan region of India mixed forest, such as taiga, are found according to their altitude where evergreen forest and deciduous species are found.
Conservation of Natural Vegetation and Wildlife:
- Forests are our wealth and provide a natural habitat for many species of animals.
- Plants and animals together maintain the ecosystem.
- Change in climate and human activities lead to the loss of forest cover which affects the plants and animals of that area.
- The major factors that impact forest cover are
- deforestation
- soil erosion
- forest fires
- are a threat to both plants and animals in a region
- can be caused by lightning, human carelessness or Arson
- landslides
- Several species of animals have become extinct or endangered due to the loss of their natural habitat and indiscriminate killing.
- Poaching
- is one of the major reasons resulting in a sharp decline in the number of particular species
- refers to the killing of animals for collecting and trading their hides, skins, nails, teeth, horns and/or feathers
- Animals like the tiger, lion, elephant, deer, black buck, crocodile, rhinoceros, snow leopard, ostrich and peacock are the most vulnerable to poaching.
- The best way to conserve the different species of plants and animals is by
- educating people about their importance in our ecosystem
- having a good communication network and efficient patrolling in forests to monitor the occurrence of forest fires
- creating and developing
- National parks - a natural area protected against human development and pollution having the aim of protecting and conserving specific ecosystems for the present and future generations.
- Biosphere reserves - protected areas created to maintain a balance relationship between conservation and development of flora and fauna.
- Wildlife sanctuaries
- conserving natural habitats like lakes, wetlands and creeks to protect the natural resources and ecosystems in those areas
- organising and encouraging awareness programs like social forestry and Vanmahotsava at the regional as well as community level
- The Indian constitution has a directive principal under Article 48A for forest conservation.
- It is the ethical duty of every citizen to conserve plants and animals.
- At the international level, CITES - “Convention on International Trade in Endangered Species of Wild Flora and Fauna” - has been set up to make sure that wildlife and plant species do not become endangered or extinct because of their trade.