SOIL

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SOIL
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• Soil is one of the most important natural media
  which support the growth of plants. Soil is, a
  complex mixture of several components. Various
  physical, chemical and biological activities take
  place continuously in the soil. Lets discuss
  about the formation of soil, constituents of soil
  and their utility.

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COMPOSITION OF SOIL
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• The composition of soil differs for different
  types of soils. It depends upon the type of rock
  from which the soil is formed.
• The constituents of soil are -
• 1. Water
• 2. Air
• 3. Organic matter of Humus
• 4. Living Organisms
• 5. Inorganic matter and nutrients
• 6. Minerals

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1. Composition of Soil in Water

• Water is generally found in all types of soils.
  Plants do not grow in dry soils. Soil water is
  present between and at the surface of soil
  particles.

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2. Composition of soil in Air

• Air is present in the spaces between soil
  particles. The amount of air present varies from
  soil to soil. Soil texture from the atmosphere
  above the ground in the sense that it is normally
  lower in oxygen content and higher in carbon
  dioxide content. Soil air is needed for the
  respiration of plants.

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3. Composition of soil in Organic matter or Humus

• The decomposition of dead organisms (plants.
  Animals. Micro-organisms) adds organic matter to
  the soil. The excreta of organisms are also added
  to the soil.

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4. Composition of soil in Living Organisms

• Various kinds of living organisms are present
  in the soil. These include microflora (bacteria,
  actinomycetes, algae and fungi) and microfauna
  (protozoa, nematodes, insects and other
  organisms). You might have noticed earthworks and
  ants coming out of the soil during rainy season.

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5. Composition of soil in Inorganic matter and
nutrients

• Soil gets inorganic nutrients from the parent
  rock from which it is formed. The whole process
  of soil formation is generally divided into two
  stages i.e., weathering and soil development. The
  process of weathering involves the breakdown of
  bigger rocks into smaller mineral particles.
  Mineral particles are modified into different
  soil types through interaction between
  biological, climatic and other factors. Inorganic
  nutrients are also added to the soild from time
  to time in the form of manures and fertizers.
  Plants do not develop well in the absence of
  these nutrients. The inorganic matter of the soil
  is the combination of minerals and inorganic
  salts.

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6. Composition of soil in Minerals

• Different minerals found in the soil are called
  nutrients. Plants require at least sixteen
  different nutrients for their growth. Some of
  these nutrients are needed in large amounts and
  are called macronutrients. The macronutrients
  required for the growth and development of plants
  are carbon. Hydrogen, oxygen, nitrogen,
  phosphorus, potassium, calcium, magnesium and
  sulphur. The macronutrients are also called major
  elements or microelements. Among the nine
  macronutrients, nitrogen, phosphorus and
  potassium are needed in greater amounts then the
  others. These three are called primary nutrients.
  

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Soil is Natural Resource

• Soil is very useful and very important natural
  wealth. It is formed in a natural process. The
  plants grow on the soil collecting water, mineral
  salt, cultivation is done on the surface of the
  earth. We cant grow paddy, jute and wheat
  without soil. Besides this potatoes, ground nuts,
  ware also cultivated on the sandy soil.
  Vegetables are plenty cultivated on different
  types of soil. Beside this soil is used to build
  houses, roads and earth and to make pots.
  Different kinds of mineral wealth are also
  collected by digging the soil.Different kinds of
  micro organisms like ants, white-ants also live
  in the soil. Besides this, cows, buffalos, camels
  and horses live on the land. So soil is very very
  useful to us.

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Quality of Soil

• Soil may be coarse (sandy) medium (loamy) or
  fine (clayey). The relative amount of primary
  particles of sand. Silt and clay, determines the
  soil texture. The different types of soil
  particles vary in size. Like
• Gravel particles 2.0 to 5.0 mm in size
• Sand particles 0.2 to 2.0 mm in size
• Clay particles less than 0.2 mm in size

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Pore space Soil particles Molecular layer of water
Particles

• Depending on the amounts of different particles,
  soil can be classified into three groups
• Sandy Soil
• Clayey Soil
• Loamy Soil

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a. Sandy Soil

• Sandy soil contains 70-85 sand and some clay.
  Due to bigger-sized particles, sandy soil does
  not have good water-holding capacity. There is a
  lot of air present in this soil. Sandy soil is
  not suitable for the growth of plants.

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b. Clayey Soil

• In this soil, a high percentage of clay, very
  less sand and some amount of humus are present.
  This soil is better than sandy soil for the
  growth of plants. There is no air in this soil.
  Clayey soil has a very good water-holding
  capacity.

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3. Loamy Soil

• Loamy soil is made up of sand, clay and humus.
  This soil had good water- holding capacity and
  air is also found in the Soil. The plants also
  obtain optimum quantities of mineral salts from
  this soil. Loamy soil is the best for the growth
  of plants.

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Soil is Classified as six Types

• Black Soil
• Red soil
• Laterite Soil
• Desert Soil
• Mountain Soil
• Alluvial Soil

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BLACK SOIL

• This soil is created by the discharges of
  Volcanoes. One can find magnesium and iron in it.
  It is very useful for the production of cotton
  and sugar-cane. It can keep water very well. This
  soil is available in Maharastra, Andhrapradesh,
  Madhyapradesh and Gujarat.

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RED SOIL

• Red soil is created by the erosion of Igneous
  rock. It looks red as there enough iron-oxide.
  This soil is very fertile as it is constituted by
  small ingridents. This soil can be found in
  Tamilnadu, Karnataka, Andhrapradesh, Orissa
  Jharkhand.

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LATERITE SOIL

• This is red color.This is a mixture of clay and
  pretty pebbles in it. It is sterile and not fit
  for agriculture.This soil can be found in the
  mountainous regions of Orissa, Karnataka, Kerala
  and Assam.

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DESERT SOIL

• This soil is mainly constituted by the mixture
  of sand. There is no organic materials in this
  soil. This soil can not be used in agricultural
  purposes due to lack of water. This soil is seen
  in the dry regions of India like Rajasthan,
  Punjab and Hariyana.

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MOUNTAIN SOIL

• This soil is created by the decomposition of dry
  leaves and organic materials. It is very fertile
  as it is mixed with organic materials. This soil
  can be found in the mountain regions of Mahalaya,
  Arunachal Pradesh and Jammu Kashmir.

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ALLUVIAL SOIL

• This soil is stored in the river valley or low
  lands of the plateau or higher regions. It is
  very fertile. One can find clay, sand and small
  pretty pebbles in it. It is found in
  Uttarpradesh, Hariyana, Bihar, West- Bengal
  Andhrapradesh.

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POLLUTION OF SOIL

• Soil pollutes like air and water. The microbes,
  animals and plants are affected with the polluted
  soil.
• Plants and crops do not grow in the polluted
  soil. The fruits, vegetables and crops produced
  from the affected soil are also polluted.

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CAUSES OF SOIL POLLUTION

1. Different kinds of fertilizer and pesticides in
   order to produce more, causes soil pollution.
2. Sand spreads over the field due to flood and
   slain water of the ocean pollute the soil.
3. Except the industrial waste different types of
   materials like lead, zinc, arsenic, cupper,
   cadmium dust from the mines also pollute the
   soil.

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• Maximum use of plastic bags also pollutes the
  soil.
• The various waste materials like rubber, leather
  shoes, plastic covers , polythene and leather
  shoes are thrown outside and pollute the soil.
• The industrial waste also pollutes the soil. The
  solid and liquid waste from paper mills, ash from
  thermal power station, unrefined oil from oil
  refinery, acid mixed water from leather and
  rubber industries pollute the soil

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THIS IS THE BEGINING WE LIVE IN SOIL