3. Improvement In Food Resources
Organic Farming :
Manures are natural fertilizers. They are bulky sources of organic matter which supply nutrients in small quantities but organic matter in large quantities. Manures include farmyard manure (FYM). Compost, green manures, vermicompost, etc.
Advantages of Manures :
Manures affect the soil in following three ways :
The manures enrich the soil with nutrients. They replenish the general deficiency of nutrients in the soil. Since manures contain nutrients in small quantities, they are needed to be applied in large quantities.
The manures add organic matter (called humus) to the soil which restores the soil texture for better retention of water and for aeration of soil. For example, organic matter present in the manures increases the water holding capacity in sandy soils and drainage in clayey soil
The organic matter of manures provide food for the soil organisms (decomposers such as bacteria, fungi, etc.) which help in making nutrients available to plants.
Thus, organ is manures help to improve the physical properties of soil, reduce soil erosion, increase the moisture holding capacity of soil and above all these advantages, they are low cost nutrient carriers.