What is the role of pseudomonads in the soil ?

What is the role of sun in the formation of soil?

What is the role of soil testing centres?

What is top soil?

What is the role of soil in better yield ?

(a) What is soil erosion? Stateany one way by which it can be prevented. (b) What is humus? What is the role of earthworms in increasing the quantity humus.

What is the role of wind in soil formation?

What is the role of plants in controlling air pollution and soil erosion?