CLASS VIII - NATURAL RESOURCES: LAND SOIL & WATER

NATURAL RESOURCES: LAND SOIL & WATER

Topics that we will cover in this are:

    1. Natural Resource – Land, Soil, Water, Forest, etc.

    2. Land: the most important natural resource. 

    3.Land use pattern (India and the World).

    4. Factors affecting the land use pattern.

    5.Land Degradation. Common causes of land degradation. Measures to control land degradation.

    6. Landslides and some mitigation strategies.

    7. Soil, factors of soil formation and the soil horizons.

    8. Different types of soils (i.e. Alluvial Soil, Black Soil, Red Soil, Laterite Soil, Desert Soil and Mountainous Soil).

    9. Degradation of soil and the methods used for the conservation of soil.

    10. Water, distribution of water bodies on the earth's surface, Hydrological Cycle.

    11. Problems related the availability water and the ways to conserve water.

 

Before learning lets remember some Important points :

• Land is the most important natural resource.
• It covers only 29% of the total earth's surface and all this area is not habitable, rest 71% is covered with water bodies.
• 90% of the total world population resides in 30% of the land area and remaining 70% is uninhabitable or sparsely populated.
• Characteristics of land and climate are the two important factors for the uneven distribution of the population in this world.
• Areas having moderate climate, level land and fertile soil are the ideal conditions for the human habitation. These areas are densely populated because they support various economic activities.
• On contrary, rugged topography, steep slopes of mountains, low lying areas prone to water logging, deserts areas, thick forests are uninhabitable. These areas are less populated.

 

Land

A very important natural resource, Land covers 30% of the earth’s surface and not every part is habitable. The land is also having mountains, polar regions, swamps which can not be converted for any purpose.

Land Use: The land is used for different purposes such as agriculture, forestry, mining, building houses, roads and setting up of industries. This is commonly termed as Land use. The land use pattern  varies from region to region. the land use is fully dominated by the population density of any region.

Areas that are sparsely populated or uninhabited	Densely populated areas
Rugged topography Steep slopes of the mountains Low-lying areas susceptible to water / Swamps High altitude regions / Regions with extreme climatic condition.	Plains River valleys These are lands suitable for agriculture

Factors effecting land use are: -

A. Physical Factors: These are the natural factors.

1. Climate  - Moderate or Extreme (Very High or Very low)         

2. Topography - (Graph on the Top) Plains, Plateaus, Mountains           

3. Water availability    -   Basic use is : domestic, agricultural use       

4. Soil             -  Fertility of Soil

5. Availability Minerals - Development of mining and industrial sites there

B. Human Factors: 

1. Population Density - If population is more then to fulfill their requirement the land will be used for- more habitation lands, roads, shopping complex, but here the land under agriculture will be less, as it will be converted to urban area.

2. Technology - On the same land we can have metro, roads & flyovers. the same land is used thrice due to technology.

are also important factors of land use pattern.

 

Land can be divided on the basis of ownership:

1.   Private: This type of land is used by individuals, according to their needs.

2.  Common: Community land is used by people jointly for common use. Private land owned by individuals whereas community land is owned by the community for common uses such as the collection of fodder, fruits, nuts or medicinal herbs. Another name for community lands is common property resources. 

 

• Land is limited but not human wants. It is increasing day by day.
• The change in the pattern of land use represents or shows the change in human need, requirement, socaiety.
• Even though people’s demands are ever growing availability of land is limited thus leading people to encroach land to build commercial areas, shopping complexes in urban areas and to expand agricultural land in rural areas.
• This expansion of agriculture and construction activities also lead to major threats :
• a. land degradation
• b. landslides
• c. soil erosion
• d. desertification.
• Today these are the major threats to the Enviornment.

Land Degradation: 

It is the decline in the productive capacity of land for some time or permanently.

Land degradation is defined as the reduction or loss of the fertility of the land due to natural(heavy rainfall). we can say Land degradation is due to the activities of human which loses all the fertility and quality of soil. This is very dangerous to nature which causes further disasters.

Common causes of land degradation are:

Listed below are few causes of land degradation :

1. Deforestation

2. Overgrazing

3. Urbanization

4. Dumping of Chemical Wastes

5. Excessive use of Fertilizers

6. Bad Farming Techniques

7. Soil pollution

8. Soil Erosion

9. Overgrazing

10. Extraction of minerals at a repeated stage

11. Drought

Some of  the measures to control  land degradation are:

Listed below are few control measures of land degradation :

1. Constructing retention walls in the mountain areas to stop landslides.

2. Land Reclamation

3. Regulated use of chemical fertilizers and pesticides

4. Afforestation

5. Check on Overgrazing

6. Control of Mining Activities

7. Sheltering belts are planted for plants

Landslides:

Sliding of huge debris, rocks and other material down the slope is known as "Landslides". Landslides occur along with earthquakes, floods and volcanic eruptions.Landslides are common in mountainous regions and deep slopes.

 

Mitigation Strategies:

1. Construction should be done using proper engineering methods.

2. Constructing retaining walls

3. Improving drainage and slope management system

4. Proper land use planning

5. Afforestation

 

SOIL

• THE UPPERMOST LAYER OF THE EARTH'S CRUST IS KNOWN AS SOIL. IT IS MADE UO OF LOOSE ROCK FRAGMENTS AND HUMUS.

             (Humus is a dark coloured stable form of organic matter that remains after most of plant or animals' residues have decomposed).

• MOST OF THE FOOD ITEMS LIKE WHEAT, RICE, PULSES, FRUITS, VEGITABLES, ETC. ARE OBTAINED FROM PLANTS THAT GROW ON SOIL.

 

Factors of Soil Formation:

1. Relief – Altitude and slope determines the accumulation of soil.

2. Parent Rock – It determines, colour, texture, chemical properties, mineral contents, etc.

3. Climate – Rainfall and temperature influence rate of humus and weathering.

4. Time – It determines thickness of soil profile.

5. Organisms – Microorganisms and vegetation affect the rate of humus formation.

 

Soil Horizons:

Soil profile refers to the different layers of the soil. There are four different layers:

1. Top Soil:  It is the uppermost layer.Rich in humus and minerals.Consists of Sand, Silt & Clay.

2. Sub Soil: It lies below the top soil and supports moisture

3. Weathered Rock

4. Bed Rock: Consists of solid layer of unweathered Rock.

 

Types of Soil

Soils are classified on the basis of colour, texture, fertility, mineral content, etc. Broadly, soil is classified into six types: -

1.   Alluvial Soil

2.   Black Soil

3.   Red Soil

4.   Laterite Soil

5.   Desert Soil

6.   Mountainous Soil

 

1. Alluvial Soil:

It is the most important and most fertile type of soil found in India covering about 40 per cent of the total land area.Soil is formed by the deposition of sediments brought down by the rivers.The alluvial soil is found mostly in the Northern Plains and Coastal Plains of India.The fine particles of sand, silt and clay are called alluvium. The alluvial soil can be divided into old alluvium, also called Bangar, and new alluvium, called Khadar.

2. Black Soil:

The black soil is also called the Black Cotton Soil. Cotton grows best in this soil.Black soil is formed from the weathering of the igneous rocks.The black soil is mostly found in the Deccan Trap, covering large areas of Maharashtra, Gujarat and western Madhya Pradesh. It is also found in some parts of Godavari and Krishna river valleys, covering parts of Karnataka, Andhra Pradesh and Tamil Nadu.

3. Red Soil:

Red soil is derived from the weathering of the igneous and metamorphic rocks.The red colour is due to the high percentage of iron contents.Red soil is found in the southern and eastern parts of the peninsular plateau.

4. Laterite Soil:

The laterite soil is widely spread in India and is mainly found on the summits of the Western Ghats, Eastern Ghats, Rajmahal Hills, Vindhyas, Satpuras and Malwa plateau.Due to intensive leaching, the laterite soil generally lacks fertility and is of low value for crop production. But when manured and timely irrigated, the soil is suitable for producing plantation crops like tea, coffee, rubber, coconut, etc.

Leaching is a process in which heavy rains wash away the fertile part of the soil.

5. Mountain Soil:

The mountain soil is generally found on the hill slopes covered with forests.This type of soil is found in the Himalayan region, the Western and Eastern Ghats and in some parts of the Peninsular India.This soil is rich in humus, but poor in potash, phosphorus and lime.This soil is especially suitable for producing plantation crops, such as tea, coffee.

6. Desert Soil:

The desert soil is found mostly in the arid and semi-arid regions, receiving less than 50 cm of annual rainfall.Such regions are mostly found in Rajasthan and the adjoining areas of Haryana and Punjab. The Rann of Kachchh in Gujarat is an extension of this region.The desert soil has sand (90 to 95 per cent) and clay (5 to 10 per cent).

 

 DEGRADATION OF SOIL

Soil erosion is the degradation of soil by human activities. Following are  the factors responsible for  the soil erosion:

1. Deforestation

2. Overgrazing

3. Construction

4. Overuse of Chemical Fertilizers

5. Pesticides

6. Natural Calamities (Flood, landslides, etc.)

 

CONSERVATION OF SOIL

Soil conservation means protection, preservation and proper utilization of the soil.Some methods of soil conservation are:

1. Mulching – Bare ground between plants is covered with a layer of organic matter like straw. It helps to retail soil moisture.

2. Contour Ploughing – Ploughing along contours can decrease the flow of water down the slopes.

3. Terrace Cultivation – Steps can be cut out on the slopes making terraces.

4. Strip Cropping – Strips of grass are grown between the crops. This breaks the force of wind.

5. Shelter Belts – Rows of trees are planted to create shelter. Thus, the speed of wind is reduced.

6. Rock Dam – Rocks are piled to slow the speed of wind.

7. Contour Barriers – Stones, grass and soil are used to make barriers. Trenches are made in front of the barriers to collect water.

8. Afforestation, Crop Rotation, Control over Deforestation and Overgrazing, etc.

WATER

THREE-FOURTH OF THE EART'S SURFACE IS COVERED WITH WATER.

 

Some Facts and Figures of Water:

1.   97 % of the total volume of water is covered by Seas and Oceans

2.   Out of 3% of the fresh water available, nearly 2% is in the form of "ICE" and is found in glaciers in Antarctica, Greenland, mountain regions, etc.

3. Only 1% of water is fit to use. It is found as underground water, surface water in rivers and lakes and also, water vapors' in the Atmosphere.

 

Water is available in three forms:

1.   Water vapor's

2.   Water in ocean, lakes & rivers

3.   Ice in the glaciers & ice caps

 

The fresh water is continuously being renewed and recharged through hydrological cycle.

Usage of Water:

1. Drinking                  

2. Bathing                  

 3. Washing          

4.  Cooking             

5. Irrigation

6. Generating Electricity         

7. Water used in Industries         

8. Construction, etc.

 

PROBLEM OF WATER AVAILABILITY

• Water is available in abundance and is renewable. Then why we suffer from water scarcity?
• Water is not evenly divided around the world. Some places have lots and others have very little. Water supply is a big problem in some countries like, Africa, West Asia, South Asia, etc.
• According to Mr. Falkenmark (a Swedish Expert), Water Stress Indicator, a country or region is said to experience "water stress" when annual water supplies drop below 1,700 cubic metres per person per year. At levels between 1,700 and 1,000 cubic metres per person per year, periodic or limited water shortages can be expected. When water supplies drop below 1,000 cubic metres per person per year, the country faces "water scarcity".

 

CONSERVATION OF WATER

Some of the important ways to conserve water are: -

1.   Decrease of water pollution: Discharge of untreated sewage, agriculture chemicals & industrial effluents.

2.  Proper irrigation method:

      (a) Sprinklers can be used to irrigate very large area.

      (b) Drip irrigation can be used in dry regions, where evaporation is very high.

3.  Water Harvesting Method: This water can be used for cleaning, washing, gardening, etc.

4.  Water conservation in the home: -

• Check faucets and pipes for leaks.
• Check your toilets for leaks.
• Use your water meter to check for hidden water leaks.
• Install water-saving shower heads and low-flow faucet aerators.
• Put plastic bottles or float booster in your toilet tank.
• Insulate your water pipes.
• Take shorter showers.
• Turn off the water after you wet your toothbrush.
• Use your dishwasher and clothes washer for only full loads.
• When washing dishes by hand, don't leave the water running for rinsing.