humus the organic material that is derived from the breakdown of plant and animal material occurring in the surface layers of the soil. Keywords: Soil horizon, fertility, humus, soil genesis, leaching, degradation, erosion. humus hyo͞o´məs , organic matter that has decayed to a relatively stable, amorphous state. A humic acid is any of a variety of organic acids obtained from organic constituents of soil (humus), coal, and peat. Humus is black and colloidal in nature, coa Definition - What does Humic Acid mean? Humus is rich in carbon and is generally acidic as a result of its humic acid content. Contents 1. It is organic because of accumulation of carbon and is hence dark in colour. Mollisol, one of the 12 soil orders in the U.S. humus definition: 1. dark earth made of organic material such as decayed leaves and plants 2. dark earth made of…. Find definitions for: hu•mus. geography. In some parts of the world, windblown dust and silt blanket the land. Humus is formed by the decomposing action of soil microorganisms (e.g., bacteria and fungi), which break down animal and vegetable material into elements that can be used by growing plants. humus (hyo͞o`məs), organic matter that has decayed to a relatively stable, amorphous state.It is an important biological constituent of fertile soil soil, surface layer of the earth, composed of fine rock material disintegrated by geological processes; and humus, the organic remains of … ... humus: Meaning and Definition of. This process can occur naturally in soil, or in the production of compost. There he would find the following definition: “Humus, black-brown matter in the topsoil, is produced by the putrefaction of vegetable and animal matter. I - Soil Geography - Maria Sala, Xavier Ubeda and Sara Bernia ©Encyclopedia of Life Support Systems (EOLSS) SOIL GEOGRAPHY Maria Sala, Xavier Ubeda and Sara Bernia Department of Physical Geography, University of Barcelona, Spain. Humus is defined as black organic matter formed in soil due to the decay of dead plant and animal matter. Humus is a complex organic substance resulting from the breakdown of plant material in a process called humification. Answer. GEOGRAPHY – Vol. They are highly arable soils used principally for growing grain It is also a key component of ocean water, dystrophic lakes, and upland streams. Brush up on your geography and finally learn what countries are in Eastern Europe with our maps. Learn more. It is an important biological constituent of fertile soil . What is Humus? Mollisols are characterized by a significant accumulation of humus in the surface horizon, or uppermost layer, which is almost always formed under native grass vegetation. Humus definition is - a brown or black complex variable material resulting from partial decomposition of plant or animal matter and forming the organic portion of soil. Soil Taxonomy. This layer of fine, mineral-rich material is called loess. 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