Slide 1

LAND & SOIL

MAJOR POINTS

Land resources. India land resources. Land degradation and land conservation Soil resources. Types of soil. Layers of soil. Depletion of Soil Fertility and Soil Erosion Soil conservation.

LAND

Land is a very important resource. It meets all our basic needs of food, clothing and housing. It provides habitat for animal life, regulates water, nitrogens and carbon cycles and acts as a storehouse for ground water, minerals and fossil fuels. Soil cover is another vital natural resources that makes agricultural practices possible and provides food grains and industrial raw material.

LAND RESOURCES

Land covers about 29% of the total area of the Earths surface and of this small percentage, a large part is not habitable because it is ice or snow covered, too rugged or steep, climatically, unsuitable, waterlogged, forested or a desert. The quality and distribution of land has a major role in deciding its usage.

LAND RESOURCES Land can be divided on the basis of private land and community land. The land use pattern of a country changes over time due to physical factors, population distribution, development in technology, land tenure, government policy and other economic and human factors. 66% of the world population is concentrated in the subtropical and mid-latitude zones.

PRIVATE LAND: The land that is owned by individuals.

COMMUNITY LAND: The land which is owned by the community. Community land is the common property of all.

WORLDS LAND USE

INDIA- Land resourcesIn India the total land area is 3.28 million sq km30% is mountains, 27% is covered by plateaus and 43% is plains. The plains are best suited to agriculture. The mountains and plateaus are rich in forest resources and minerals.

India has a very high percentage of arable (cultivable) land, i.e. 57%. It goes to the credit of Indian farmers that with only 4% of area under pasture, they are sustaining the largest cattle population in the world.

LAND DEGRADATION

Soil and liquid waste is constantly being dumped on the land. Twenty- three per cent of the worlds usable land has been degraded and its productivity has been reduced. The main causes of degradation are deforestation, overgrazing, agricultural mismanagement, establishment of industries and urbanization.One- third of the Earths land area(50 million sq km) has been affected by desertification, especially in Asia, Africa, and around the Mediterranean.

CONSERVATION OF LAND RESOURCES

We need to conserve our land resources for future generations. Land use must be planned properly to provide best results. Suitable methods that should be adopted to conserve our land resources are:

Check soil erosion. Check desertification. Control waterlogging of soil. Afforestation. Land reclamation.

Regulated use of chemical pesticides and fertilizers. Check on overgrazing. Reclaim wasteland so they are brought back to other uses. Increased productivity of the land with improved farming methods such as the balanced use of manures and fertilizers, organic farming, crop rotation and multiple cropping.

SOIL RESOURCES Soil forms the thin upper layer of the Earths crust. It is made up of disintegrated rock and decayed remains of plants and animals in the form of humus; takes thousands of years for one centimetre of soil to form. The importance of soil lies in its fertility and its capacity to produce crops. Soil is formed by the physical and chemical weathering besides the biological process of decay of plant and animal matters.

Soil formation is controlled by the following factors:

Nature of parent rock, from which the soil is derived, determines the physical and chemical composition of soil.

Relief or topography which affects the drainage of the area. Soils are very thinly spread over mountain slopes and accumulate in deep layers in the lowlands.

The climate, especially temperature and precipitation are significant. Frequent changes in temperature can lead to quicker soil formation.

Time is important in determining the depth of the soil and its age.

Organisms present in the soil help to add humus, thereby increasing the water retention capacity of the soil.

COMPOSITION OF SOIL Soil has of organic and inorganic components. Organic elements include the decayed remains of vegetation and animals, i.e. humus. The inorganic elements include mineral and salts such as nitrogen, potassium, magnesium, sulphur, phosphorous, calcium and iron.

LAYERS OF SOIL A soil profile is a section showing successive layers of soil which would appear if you cut straight down into the soil. Soils are generally formed in layers. Soils have four main layers.

TYPES OF SOIL The best soils are found in river valleys. The valleys of rivers Nile in Egypt, Chang-Jiang in China, Ganga in India have rich soil. In temperate grasslands, soils are dark, rich in humus and are called chernozems. Soils of semi-arid areas, rich in minerals and humus are called pedocals. Desert soils have sufficient minerals but lack water. Soils in humid climates are acidic, but have less humus especially under cold conditions as in coniferous forests. They are called Pedalfers.

TYPES OF SOILOCCURENCECHARACTERISTICSCROPS GROWNAlluvial soilNorthern plains and deltas in South India.Clay, silt, and sand. Very fertile.Rice, wheat, sugarcane, cotton and pulses.ii. Black soil, regur or blackNorthwest of peninsular India, valleys of Godaveri, Krishna, and Narmada.Moisture retentive, sticky when wet and cracks when dry. This areates the soil.Cotton, tobacco, oil seeds and sugarcanes.iii. Red soilEastern Deccan Plateau, Tamil Nadu, Kerala and Orissa.Coarse, porous; does not retain moisture. High iron content.Wheat, rice, cotton, grown with irrigation and fertilizers.iv. Laterite soilThe hills of eastern and western ghats and Assam.Acidic and porous. Thus needs to be enriched with fertilizers.Coffee, rubber, cashew, tapiocav. Desert soilNorthwest India in Rajasthan, north Gujarat and S.PunjabLoose, porous, coarse, alkaline.Maize, wheat, and millets grown with irrigation of dry farming.vi. Mountain soilHilly areas of Jammu and Kashmir and SikkimVery thin layer of soilTea, coffee, and medicinal plants.

ALLUVIAL BLACK SOIL DESERT SOIL LATERITE MOUNTAIN RED SOIL

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DEPLETION OF SOIL FERTILITYSoil can become unproductive by erosion, overuse and mismanagement in agricultural methods. The removal of the top layers of soil on a larger scale by rainwater, wind or humans is called soil erosion. The degree of soil erosion depends on many factors soil components or structure, texture of soil, climatic conditions, slope of the land and cultivation methods. For example: gully erosion and sheet erosion.

Soil erosion Gully erosion

SOIL CONSERVATIONSoil conservation is an effort made by humans to prevent soil erosion and thereby retain the fertility of soil. Soil can be conserved by terrace farming, contour ploughing, multiple cropping, inter cropping, preventing wasteful practice of slash and burn, control of deforestation, promoting planting of trees and plugging of gullies, and shelter belts.

TERRACE FARMING: It is the practice of cutting steps in the hill slopes to provide flat land for cultivation and check the soil erosion.

CONTOUR PLOUGHING: The ploughing of land along the contour in a parallel way instead of up and down the slope.

Contour ploughing

Terrace farming ->

STRIP CROPPING: Sowing in the space between the rows of one crop with another crop instead of leaving it uncultivated.

Strip cropping Strip Cropping

SHELTER BELTS: The rows of trees planted to check wind speed and reduce erosion of the soil by winds.

WE HAVE LEARNED MUCH ABOUT LAND AND SOIL, NOW LETS TAKE A TEST

One word:Soil found close to the river valleys:Soils that are found in temperate grasslands which are dark and rich in humus:Growing crops on steps along hillsides:iv. Land with little or no vegetation:

ANSWERS

ANSWERSOne Word:

i. Alluvialii. Chernozemsiii. Terrace farmingiv. Desertification

By looking at the figure 1.1 tell from which type of soil these bricks are made.

Fig. 1.1Fill the blanks:

D_ f__es_a_ion.

_ver__zing.

P_d_l__r_.

ANSWERS

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ANSWERSLaterite soil.

Fill in the blanks:

Deforestation

Overgrazing

Pedalfers

THANK YOU by : YUVRAJ JOSHI editing by : YUVRAJ JOSHI c