Soil Presentation

By SIDDHESH & RISHAB FROM VII E

Soil is a thin layer of material on the Earth's surface in which plants have their roots. It is made up of many things, such as weathered rock and decayed plant and animal matter.

COMPOSITION OF SOIL Soil is made up of : SOIL PARTICLES MINERALS HUMUS WATER AIR SOIL ORGANISMS

SOIL PROFILE O-HORIZON: is the upper most layer composed of organic matter A-HORIZON: is the soft dark porous layer just below the O-HORIZON B-HORIZON: is below the A-HORIZON. It is formed due to leaching and accumulation of materials from the above layers. The colour of this layer is due to presence of oxides of iron and aluminium or calcium carbonate leached from the A-HORIZON C-HORIZON: is the layer below B-HORIZON. It is made up of small lumps of rocks produced by weathering. It resembles the underlying the parent rock. D-HORIZON: is the hard bed rock which forms the lowermost layer. Generally it is not considered as a part of soil.

SOIL PROFILE O-HORIZON A-HORIZON B-HORIZON C-HORIZON D-HORIZON

TYPES OF SOILS SANDY SOIL CLAYEY SOIL LOAMY SOIL SILTY SOIL ALLUVIAL SOIL BLACK SOIL RED SOIL DESERT SOIL MOUNTAIN SOIL MARSHY SOIL

Sandy soil: is light and porous. Water holding capacity is very less It does not support plant growth

Clayey Soil: has fine clay particles remaining together. Water holding capacity is high It supports plants like Mango, Jackfruit, Black plums etc

Silty soil: has smooth particles. Water holding capacity is high Crops like pulses, cotton, jute, paddy etc are grown

Loamy Soil: is a mixture of clay, sand silt. Water holding capacity is good. Good aeration and good water movement.. Regarded as best soil for plant growth

Alluvial soil: is a mixture of sand clay and silt formed by sediments brought down by a river. Very fertile. Water holding capacity is good Suitable for cultivation of sugarcane, rice wheat cotton, gram etc.

Black soil: is formed from weathered lava rocks. It is clayey. Water holding capacity is good. Very fertile. Suitable for cultivation of jowar, wheat sugarcane, cotton,gram etc

Red soil: is red due to the presence of large amounts of iron oxides. Water holding capacity is good. Not fertile Suitable for growing vegetables, ragi ,rice and tobacco

Desert soil: is arid and sandy due to mechanical weathering of rocks in desert. Water holding capacity is low Plants like cactus can grow.

Mountain soil: includes forests and hills Rich in humus Very fertile.

Marshy soil: found in the continuously water logged areas. Contains iron and varying amounts of humus.

SOIL : HABITAT FOR ORGANISMS Bacterias and microbes increase the soil fertility

Bacteria in soil

Microbes in soil

SOIL : HABITAT FOR ORGANISMS Fungi: are microganisms which do not have chlorophyll. They are saprophytes and survive on dead and decaying matter.They make the soil fertile by breaking down the dead organisms and releasing simple nutrients in the soil.

SOIL : HABITAT FOR ORGANISMS Insects: A large number of Amoeba, worms, earthworms, snails, ants grasshoppers, snakes, mammals are found in soil. Organisms such as earthworms, rats, ants make the soil porous and facilitate root penetration

Earthworms

Ants

Rats

Soil is a facilitator for percolation and retention of water. Ground water accumulates mainly from rains that percolates through soil. It also collects from water that seeps into the ground from lakes and ponds. Ground water provides freshwater in many areas in the world.

PICTURE SHOWING THE FLOW OF GROUNDWATER