The word "organic" pertains to the use of non- chemical fertilizers as manure and compost and the word "manure" refers to any natural substance for fertilizing the soil, especially dung or refuse. Plants are built up from the food they get, either through the chlorophyll process or from the soil. During their growing process, plants take out of the soil many elements. Hence, new food has to be added.
No organic matter may be burnt or thrown away, but must be put back into the field. This is the way nature restores and improves itself. The form of returning organic matter to the soil may take many shape: composting, mulching, green manuring, etc. Chemical fertilizers or pesticides used are minimum in this case.
Organic matter is the most important constituent of any soil because it is in organic matter that all the microbes and other minute forms of life exist. It releases plant food slowly and steadily, the way plants need to be fed. It will not leach away.
Nature has grown plants for million of years with nothing but organic fertilizers. Farm yard manure (FYM), plant residues, compost, cotton seed, etc. are natural fertilizers.
Organic matter in the soil can be both living and dead. Micro-organisms and vegetation (the soil fungi and plant roots) are living things which are vital in carrying out chemical and physical changes in the soil and they are just as important once they have died. It is from the dead remains that the plant nutrients are derived in nature by decomposing them. They improve the soil structure and makes the soil healthy.
Method of composting also comes under organic manure which involves fermentation of organic residues in the presence of moisture in closed conditions: It increases the availability of plant nutrients, destroys pathogens and eliminates the unfavourable odours.