Components of Soil – Effects & Importance

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Hi, Welcome to this blog on the components of Soil, Effects of Soil and importance.

Table Of Contents

  1. Components of soil
  2. Mineral or Inorganic matter
  3. Organic matter
  4. Soil water
  5. Soil air
  6. Living organisms

Soil is composed of mineral particles (sand, silt, and clay), organic matter, water, and air. These components together form the soil’s physical structure, influencing its fertility and ability to support plant life.

The soil is made up of five components which are:

1. Inorganic (mineral) matter

2. Organic matter

3. soil water

4. soil Air

5. Living organisms

Before you read through, check types of soil and Thier properties on my next article.

Mineral or inorganic matter, organic matter, water and air are collectively referred to as physical components of soil why living organisms are referred to as biological components of the soil.

1. Mineral or inorganic matter: The mineral matter represent small rock fragments of the soil. It forms the bulk of about 45% of total volume of the soil. It consist of gravel, Stones, Sand, silt and clay.

IMPORTANCE/EFFECT OF MINERAL MATTER ON AGRICULTURE

  1. It forms the solid part of the soil and provide support for plants.
  2. matter is the main source of plant nutrients such as Nitrogen, calcium, magnesium, iron, etc.
  3. It represents the home or habitat of all living organisms.
  4. Mineral matter has moderating effect on soil temperature.
  5. It also affects soil porosity.
  6. It holds water and air for both plants and animals activities.

2. Organic Matter: The organic matter represent the remains of the decomposition of plants and Animals. It’s about 5% of the total volume of the soil. Leaves, roots of Plants, the residue of Crops, animal dung etc, when deposited on the Soil, decay to form a dark colour on the upper part of the soil known as organic matter or humus.

IMPORTANCE/EFFECT OF ORGANIC MATTER ON AGRICULTURE

  1. It is very rich in plant nutrients.
  2. it prevents leaching in soil where it is present in adequate amount.
  3. It is the habitat of many soil micro-organisms.
  4. It allows for good drainage and holds water in the soil for plant use.
  5. It improves the structure of the soil by binding the particles of coarse texture soil together.
  6. It moderates the soil temperature which stimulates good development and growth of roots.
  7. It increases water holding capacity of the soil.
  8. It has buffering effects that moderate PH value.
  9. It improves soil aeration.
  10. It is responsible for the loose, friable condition of loamy soil.

3. SOIL WATER: Soil water is another components of Soil, this is referred to the water in the soil which is usually obtained either from rain or irrigation. Water represent 25% of the total volume of the solid. It is usually found in the soil within the pore spaces. When water is too much in a soil (covering the soil surface) the soil is said to be waterlogged. A waterlogged soil, can However, be improved by drainage to make such soil more productive. On the other hand, a situation where there is lack of water in the soil for a long time to the extent that plant cannot absorb water even when supplied again, results in a condition called permanent wilting points. The plant at this stage can die.

TYPES OF SOIL WATER

  • Hygroscopic water: This water is tightly held by the soil particles such that it is never available to the plant.
  • Field capacity: This is the type of water left in the soil after excess water has been drained off, following heavy rainfall. This water is available to the plants.
  • Capillary water: This is the water which rises above the water table to the soil and it is held in the fine medium pores of soil particles by surface tension. Capillary water is easily available to plants.
  • Gravitational water: This is the water which can drain from the soil under the influence of gravity. It is available to plants but is often pulled down beyond the reach of the roots.

IMPORTANCE/EFFECT OF SOIL WATER ON AGRICULTURE

  1. It helps to dissolve plant nutrient into solution form which can easily be absorbed by plants roots.
  2. Water is an important agent of weathering of rock in the soil.
  3. Hydrolysis of many food nutrients and enzymatic activities are promoted by the presence of water.
  4. Water is an essential raw material for photosynthesis.
  5. Presence of water aids easy tillage of the soil and also helps to improve the soil structure.
  6. Loss of water from plant through a process called transpiration is helpful in the cooling of the plants.
  7. It is needed for the germination of seeds.
  8. It also promotes activities of the soil organisms.
  9. It protects land from injurious effects of high temperature.
  10. It aids the Turgidity of the cell.
  11. It provides the medium for soil reactions.

4. SOIL AIR: This refers to the gases present in the soil pores found between the soil particles. The amount of soil varies, depending on the amount of soil water, the sizes of the pores spaces, the types of soil and the amount of living organisms in the soil. The percentage of air is about 25% of the total volume of the soil. The ability of air to circulate freely in the soil is called AERATION.

IMPORTANCE/EFFECTS OF SOIL AIR ON AGRICULTURE

  1. Soil air, especially oxygen, is necessary for the growth and development of plants.
  2. Soil organisms require oxygen for respiration.
  3. Oxygen in the soil promotes easy germination of seeds
  4. some plant disease organisms such as fusarium which causes dumping off are favoured by aeration.
  5. It is needed in soil reaction, particularly carbon and nitrogen cycle.
  6. Excess of carbon dioxide in soil when combined with water can cause acidity and aid weathering of rocks.

5. LIVING ORGANISMS: This refer to plants and animals which inhabit the soil. They range from microscopic organisms to bigger organisms. Some are beneficial while other are harmful to crops and livestock. The most commonly found groups of soil organisms include bacterial, fungi, virus, nematodes, insects, (e.g, termites, soldier ants), millipedes, centipedes,s earthworm, snails, reptiles, mammals, (e.g. Rats and rodents).

IMPORTANCE/EFFECTS OF LIVING ORGANISMS ON AGRICULTURE

  1. Soil organisms improve soil structure and granulation.
  2. They helped old decomposed organic materials in the soil to form humus.
  3. They also improve the aeration of the soil.
  4. They improve soil water percolation or drainage.
  5. Some organisms like bacteria helps to fix nutrients in the soil.
  6. They also increase the colloidal properties of the Soil.
  7. Some micro-organisms produce acidic materials which helps to break down rocks.
  8. Through burrowing, they leave holes for crop root penetration.
  9. Soil organisms enhances the cation exchange capacity of the soil.
  10. The increase the mineral or nutrient status of the soil.
  11. They stabilize soil pH through the increase in the soil organic matter and buffering.

In components of Soil, Soil organisms are very useful in many ways especially in soil-formation and improving the soil for the growth of crops.

Revision Questions

  1. The soil is made up of 5 components which are? List the 5 components of soil mentioned above.
  2. What are the importance/effects of soil water?
  3. What are the 4 types of soil water?
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