Components Of Soil
Soil of Class 7
Soil contains following components :
- Soil particles (gravel, sand, silt and clay)
- Humus (organic matter, formed by decomposition of death and decay of living organisms)
- Soil air
- Soil water
- Soil organisms.
The soil is composed of different types of particles of varying sizes.
The various particles are:
- Gravels – Particlesize greater than 2 mm in diameter.
- Sand particles – Particle size varies from 0.05 mm – 2 mm.
- Silt particles – Particle size ranging from 0.005 mm – 0.05 mm.
- Clay particles – Particle size less than 0.005 mm.
Humus and the micro organisms in the soil decide the quality of the soil. It causes the soil to become porous and allows water and air to penetrate deep underground. The mineral nutrients found in a particular soil depends on the rocks it was formed from.
The nutrient content of a soil, the amount of humus present in it and the depth of the soil are some of the factors that decide which plants will thrive on that soil.
A fertile soil contains a mixture of all the different-sized particles. Such a soil having mixtures of different-sized particles is called a loam or loamy soil.
Fertility of soil depends on
- Presence of organic matter and nutrients.
- Capacity of the soil to retain water and air.
- A loamy soil is best-suited for plant growth.
- The fertility of soil is threatened due to various activities of humans.