Name:T.Ponkumaran.Class:7th

Subject:scienceTopic:Different types of soil and its water absorbtion

DIFERENT TYPES OF SOIL AND

WATER ABSORBTION

WHAT IS SOIL?

Soil is the mixture of minerals, organic matter, gases, liquids and a myriad of organisms that can support plant life

TYPES OF SOIL

1.Red soil 2.Black soil 3.Alluvial soil 4.Sandy soil 5.Clay soil

Red soil

Red soils have two broad classes:

a) Red loam with cloddy structure and allow content of concretionary materials; and b) Red earths with loose, Permeable top soil and a high content of secondary concretions. Generally these soils are light textured with porous and friable structure and there is absence of lime Kankar and free carbonates. They have neutral to acidic reaction and are deficient in nitrogen humus, phosphoric acid and lime. 

RED SOIL

BLACK SOIL

BLACK SOIL

3) Black soilsThese are mostly clay soils and form deep cracks during dry season. An accumulation of lime is generally noticed of varying depths. They are popularly known as “Black cotton soils” because of their dark brown colour and suitability for growing cotton. These are also known as Indian regurs.These soils are deficient in nitrogen, phosphoric acid and organic matter but rich in calcium, potash and magnesium. 

ALUVIAL SOIL

4) Alluvial soilsThese soils occur along rivers and represent the soil materials that have been deposited by the rivers during flood. Usually they are very productive soils but many are deficient in nitrogen, humus and phosphorus. 

ALUVIAL SOIL

SANDY SOIL

These are mostly sandy soils that occur in the low rainfall track. They are well supplied with soluble salts but are low in nitrogen and organic matter and have a high pH value. These are quite productive. These are often subjected to wind erosion. 

SANDY SOIL

CLAY SOIL

Clay is a fine-grained soil that combines one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure. Clays are distinguished from other fine-grained soils by differences in size and mineralogy. Silts, which are fine-grained soils that do not include clay minerals, tend to have larger particle sizes than clays. There is, however some overlap in particle size and other physical properties, and many naturally occurring deposits include both silts and clay.

CLAY SOIL

WATER ABSORBTION

Plants get water from the soil where they grow in. If the soil can hold water, plants will grow well. But, if the soil is not able to retain, plants will either die or will need frequent watering.Ability of soil to hold water depends on the following two factors:

Water absorption tendency

The amount of water absorbed by a particular type of soil is called its water water aborption tenency. Higher is the water absorption tendency, higher is the number of plans.

WATER RETENTION TENDENCY

The time duration for which water is retained in the soil is called the water rentention tendency. Both these factors are important for plants to absorb water from soil.