BIOLOGY [2 Mark Question Answer]

Clayey soil is not very suitable for the growth of plants because it has very less air space between the soil particles. Water displaces the air due to a very high water-holding capacity and, thus, roots cannot respire due to a lack of oxygen.

A horizon is considered the most fertile layer of soil because it is soft, porous and contains lots of humus (dead and decaying plants and animal matter) which makes the soil fertile. Also, it has a good water holding capacity. Living organisms like earthworm, bacterian, fungi are also present in this layer which help in releasing nutrients in soil.

Loamy soil is considered to be the best for plant growth as it contains a lot of humus which adds nutrients to the soil. It also holds sufficient water and has enough air between soil particles which allows the water to flow freely.

Earthworms are called farmer’s friends and help in making the soil fertile in two ways :
a. as it moves through the soil, it leaves tube like passages in the soil where air and water (needed by the plants) get accumulated.
b. as it ingests the soil particles and pass out the undigested matter, it adds to the nutrients of the soil and makes the soil fertile.

A-horizon is considered to be the most fertile layer because it is soft, porous and contains lots of humus (dead and decaying plants and animals matter) which makes the soil fertile. Also it has a good water holding capacity. Living organisms like earthworm, fungi are also present in this layer which help in releasing nutrients in soil.