Organic matter (or organic material, natural organic material or MON) is matter made up of organic compounds that come from the remains of organisms that were once alive, such as plants, animals and their waste products in the natural environment. The basic structures are made up of cellulose, tannin, cutin and lignin, along with various other proteins, lipids and sugars. It is very important in the movement of nutrients in the environment and plays a role in retaining water on the surface of planet Earth.

All living organisms are made up of organic compounds, while they are alive they secrete or excrete organic materials such as feces into the soil, they shed portions of their bodies such as leaves and roots, and after the organism dies, its body begins to decompose and dismember thanks to the action of bacteria and fungi. It is possible that large molecules of organic matter are formed by polymerization of various short chains resulting from decomposed matter. Natural organic matter can vary greatly, depending on its origin, mode of transformation, age and environment, therefore its bio-physical-chemical functions present great variation depending on the types of environments.[1]​.