This document provides an introduction to organic manures. It discusses that modern agricultural practices have led to depletion of soil nutrients and increased reliance on chemical fertilizers. Organic manures help maintain soil organic matter and recycling of organic wastes is important for soil health. The document then discusses the effects of excessive chemical fertilizer use, including nutrient losses, soil acidification, and pollution of water sources. It notes the advantages of organic manures in improving physical, chemical and biological soil properties. Major organic sources are described including farm yard manure, animal wastes, crop residues, and compost. Carbon cycling through photosynthesis and decomposition is also summarized.