The importance of chemically stable humus is thought by some to jetëfertilitetit it provides to soils in both a physical and chemical sense , though some agricultural experts put a greater focus on its other features , such as its ability to suppress the disease . This help maintain soil moisture by increasing microporosity , and inkurajonformimin good soil structure.The incorporation of oxygen into large organic molecular assemblages generates many active sites that bind negatively charged positively charged ions ( cations ) of plant nutrients by making them more available to plants by ion exchange . Humus soil allows organisms to feed and reproduce , and is often described as " life - force " of soil.Yet , it is difficult to determine exactly humus , this is a very complex substance , which is not yet understood completely . Humus should be differentiated from decomposed organic matter in recent seky is rough -looking material , with original plant remains visible while fully humified organic matter is uniform in appearance ( a dark , spongy , jelly - like substance ) and amorphous in structure , and may remain as such for millennia or more . It has no particular structure , form or character . However , humified organic matter , when examined under the microscope can detect small , plant , microbial or animal bones that have been mechanically , not chemically degraded . This suggests a fuzzy boundary between humus and organic matter . In most literature , humus is considered an integral part of soil organic matter . Remains of plants (including those that have passed through an animal gut and excreted as feces ) contain organic compounds : sugars , starches , proteins , carbohydrates , lignins , waxes, resins , and organic acids . The process of decay of organic matter in the soil begins with the decomposition of sugars and carbohydrates from starch , which break down easily as detritivores initially possess dead bodies in the plant , ndërsapjesa residual lignin cellulose and break down very slowly . Simple proteins , organic acids , starch and sugars break down quickly , while crude proteins , fats and resins , waxes remain relatively unchanged for long periods of time . Lignin , which is quickly transformed the white - rot fungi, is one of the main precursors of humus , together with products of animal microbialand activity . Finally - the product of this process , humus , is therefore a complex mixture of compounds and chemicals plant life , animal or microbial origin that has many functions and benefits on earth . Earthworm humus ( vermicompost ) is considered by some the best manure sion there.