Define manure. What are different manures and how do they affect the soil?

Manure - Manures are natural fertilizers. They are bulky sources of organic matter which supply nutrients in small quantities, and organic matter in large quantities. There are different types of manures: Farmyard manure (FYM), Compost, Green manures and Vermicompost.

Manures affect the soil in following three ways:

(i) Manures enrich the soil with nutrients. They replenish the general deficiency of nutrients in the soil. Since manure contains fewer nutrients they need to be used in large quantities.

(ii) Manures add organic matter (called humus) to the soil which restores the soil texture, for better retention of water and aeration of soil.

(iii) The organic matter in manures provides food for the soil organisms, (decomposers such as bacteria, fungi, etc. which help in providing nutrients to plants.