09. Soils by Dilip Kumar Chandra
Download as PPT, PDF3 likes132 views
Soil is the top layer of the Earth's crust and is formed through the natural process of weathering of rocks over hundreds of years. Soil is made up of various layers including the top soil, sub soil, and bedrock. It provides nutrients and support for plant growth. Soil erosion by wind and water is a major threat and can be reduced through practices like forestation, contour plowing, and crop rotation.
09. Soils by Dilip Kumar Chandra
- 2. Soil is the top most layer of the earth’ crust . Soil is a mixture . Soil is very necessary for the growth of plants. Soil provides support to the plants . Soil is a rich source of organic and in organic substances .
- 3. FORMATION OF SOILFORMATION OF SOIL • Formation of soil is a natural process and it is aFormation of soil is a natural process and it is a continuous process . The soft layers of rockcontinuous process . The soft layers of rock erode due to wind and rains . Under certainerode due to wind and rains . Under certain circumstancescircumstances • Rain water collected in the cracks of rocksRain water collected in the cracks of rocks freezes and increases in volume. As a result thefreezes and increases in volume. As a result the rock breaks into small pieces. This type ofrock breaks into small pieces. This type of breaking up of rocks is calledbreaking up of rocks is called “WEATHERING OF ROCKS”“WEATHERING OF ROCKS” • Soil is formed due to changes in temperatureSoil is formed due to changes in temperature and climate.and climate.
- 4. DO YOU KNOWDO YOU KNOW Formation of one inch of soilFormation of one inch of soil takes 500- 1500 years .takes 500- 1500 years .
- 5. CONSTITUENTS OF SOILCONSTITUENTS OF SOIL • When the land is dug we see different colouredWhen the land is dug we see different coloured layers of soillayers of soil • Soil has three distinct layers.Soil has three distinct layers. • 1.1. TOP SOILTOP SOIL • 2. SUB SOIL2. SUB SOIL • 3.BED ROCK3.BED ROCK Layers of soil
- 6. TOP SOILTOP SOIL.. • The top most layer containsThe top most layer contains decayed and decaying plant anddecayed and decaying plant and animal matter. This is calledanimal matter. This is called FERTILE SOIL OR ORGANICFERTILE SOIL OR ORGANIC SOIL.SOIL.
- 7. SUB SOILSUB SOIL This is the middle layer which isThis is the middle layer which is harder than the top soil . It hasharder than the top soil . It has soluble mineral salts and organic soilsoluble mineral salts and organic soil in small quantities. This soil isin small quantities. This soil is known asknown as sub soilsub soil
- 8. BED ROCKBED ROCK This has a pieces of rock and many layersThis has a pieces of rock and many layers of rock .This form the lower and is veryof rock .This form the lower and is very hard . This can not be dug with ordinaryhard . This can not be dug with ordinary implements. This is known asimplements. This is known as “bed rock”“bed rock”
- 9. IMPORTANT FEATURES OFIMPORTANT FEATURES OF FERTILE SOIL.FERTILE SOIL. • Fertile soil is porous inFertile soil is porous in naturenature • Fertile soil is light in weightFertile soil is light in weight • Fertile soil is having capacityFertile soil is having capacity to hold waterto hold water • Fertile soil is rich inFertile soil is rich in • organic and inorganicorganic and inorganic substances.substances. EARTH WORM
- 10. TYPES OF SOILTYPES OF SOIL Soil is mainly grouped in to fourSoil is mainly grouped in to four types depending upon the colour ,types depending upon the colour , its constituents and structure ofits constituents and structure of particles .They areparticles .They are
- 11. BLACK SOIL RED SOIL ALLUVIAL SOIL LATERRITE SOIL
- 12. RED SOILRED SOIL Red soil is mainly found in SouthRed soil is mainly found in South India. The presence ofIndia. The presence of iron oxideiron oxide isis responsible for its red in colour. Itresponsible for its red in colour. It has particles of clay and sandy soil.has particles of clay and sandy soil. Ex:-Ex:-Tea and coffee.Tea and coffee.
- 13. BLACK SOILBLACK SOIL Black soil is the most suitable forBlack soil is the most suitable for agriculture. The reason for black inagriculture. The reason for black in colour is the decomposed constituents ofcolour is the decomposed constituents of the organic substances. Moisture contentthe organic substances. Moisture content is great in this soil. It is found in theis great in this soil. It is found in the northern part of Karnataka . This type ofnorthern part of Karnataka . This type of soil is suitable for the growth ofsoil is suitable for the growth of CottonCotton and Ground nutand Ground nut..
- 14. ALLUVIAL SOILALLUVIAL SOIL The soil on the beach and river banksThe soil on the beach and river banks is mainly made up of sand and is fertileis mainly made up of sand and is fertile . This soil is known as alluvial soil.. This soil is known as alluvial soil. Ex- River banks.Ex- River banks.
- 15. LATERITE SOILLATERITE SOIL Generally this soil isGenerally this soil is red or reddishred or reddish yellow inyellow in colour.colour. It looks likeIt looks like honey comb .honey comb . It has lessIt has less amount of calcium and is found in areas whereamount of calcium and is found in areas where there is heavy rainfall. When the moisture inthere is heavy rainfall. When the moisture in the soil reduces to reasonable quantity this soilthe soil reduces to reasonable quantity this soil is dug and made in tois dug and made in to bricks.bricks. By theirBy their structure and composition The soil is alsostructure and composition The soil is also classified in three types.1. sandy soil , clay soilclassified in three types.1. sandy soil , clay soil and loamy soil.and loamy soil.
- 16. EROSION OF SOILEROSION OF SOIL The running water during rainsThe running water during rains carries the soil.carries the soil.Flowing waterFlowing water Blowing wind carry soil along withBlowing wind carry soil along with them.them. The process of loss of top soilThe process of loss of top soil by wind and water is calledby wind and water is called soilsoil erosion.erosion.
- 18. CAUSES FOR SOIL EROSIONCAUSES FOR SOIL EROSION 11. Deforestation .. Deforestation . 2. Over grazing of animals in2. Over grazing of animals in grasslands.grasslands. 3. Growing the crops in the same3. Growing the crops in the same land year after year.land year after year. 4. Unscientific use of soil.4. Unscientific use of soil.
- 20. METHODS OF PREVENTINGMETHODS OF PREVENTING SOIL EROSION.SOIL EROSION. • The erosion of top soil by wind and waterThe erosion of top soil by wind and water is prevented by growing grass and trees.is prevented by growing grass and trees. • Ploughing at right angles in slopes .Ploughing at right angles in slopes . • The soil erosion on slopes can be checkedThe soil erosion on slopes can be checked by ploughing in furrows.by ploughing in furrows. • To prevent erosion of soil crops are grownTo prevent erosion of soil crops are grown in strips . This is known as strip farming.in strips . This is known as strip farming.
- 22. REVIEWREVIEW 1. What do you mean by weathering of rocks ?1. What do you mean by weathering of rocks ? 2. What are the important features of top soil?2. What are the important features of top soil? 3. Name the various types of soil.3. Name the various types of soil. 4. What is soil erosion?4. What is soil erosion? 5.What are the causes of soil erosion?5.What are the causes of soil erosion? 6. What are the preventive measures of soil6. What are the preventive measures of soil erosion?erosion?
- 23. ASSIGANMENTASSIGANMENT 1. What is soil1. What is soil 2. How soil is formed2. How soil is formed 3. Name the different types of soil3. Name the different types of soil 4.What is soil erosion4.What is soil erosion
- 24. PROJECTPROJECT Visit a near by field and collectVisit a near by field and collect different types of soil and observedifferent types of soil and observe colour and texture of soilcolour and texture of soil
- 25. 1 2 4 5 7 3 DOWN ACROSS w W I N D E R O S I O N 6 C L A Y P E S T I C I D E E A R T H W O R M W H E A T S A N D A Y P R O F I L E