Learn more. It is also a key component of ocean water, dystrophic lakes, and upland streams. Find definitions for: hu•mus. Mollisol, one of the 12 soil orders in the U.S. A humic acid is any of a variety of organic acids obtained from organic constituents of soil (humus), coal, and peat. humus hyo͞o´məs , organic matter that has decayed to a relatively stable, amorphous state. When glaciers grind rocks to a fine powder, loess can form. Answer. This process can occur naturally in soil, or in the production of compost. Loess is mostly created by wind, but can also be formed by glaciers. 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. Definition - What does Humic Acid mean? They are highly arable soils used principally for growing grain humus the organic material that is derived from the breakdown of plant and animal material occurring in the surface layers of the soil. GEOGRAPHY – Vol. It is an important biological constituent of fertile soil . Pronunciation: (hy'mus or, … It has very important constituents to keep … 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 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. 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 … Soil Taxonomy. humus definition: 1. dark earth made of organic material such as decayed leaves and plants 2. dark earth made of…. This layer of fine, mineral-rich material is called loess. What is Humus? geography. Keywords: Soil horizon, fertility, humus, soil genesis, leaching, degradation, erosion. Litterfall, plant litter, leaf litter, tree litter, soil litter, or duff, is dead plant material (such as leaves, bark, needles, twigs, and cladodes) that have fallen to the ground.This detritus or dead organic material and its constituent nutrients are added to the top layer of soil, commonly known as the litter layer or O horizon ("O" for "organic"). Contents 1. ... humus: Meaning and Definition of. It is organic because of accumulation of carbon and is hence dark in colour. Humus is black and colloidal in nature, coa Brush up on your geography and finally learn what countries are in Eastern Europe with our maps. Humus is rich in carbon and is generally acidic as a result of its humic acid content. 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 is a complex organic substance resulting from the breakdown of plant material in a process called humification. 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