Humus is a complex organic substance resulting from the breakdown of plant material in a process called humification. Learn more. A humic acid is any of a variety of organic acids obtained from organic constituents of soil (humus), coal, and peat. This layer of fine, mineral-rich material is called loess. geography. Answer. Pronunciation: (hy'mus or, … GEOGRAPHY – Vol. Contents 1. humus definition: 1. dark earth made of organic material such as decayed leaves and plants 2. dark earth made of…. humus the organic material that is derived from the breakdown of plant and animal material occurring in the surface layers of the soil. 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 is black and colloidal in nature, coa Brush up on your geography and finally learn what countries are in Eastern Europe with our maps. Find definitions for: hu•mus. 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. It is an important biological constituent of fertile soil . They are highly arable soils used principally for growing grain Humus is defined as black organic matter formed in soil due to the decay of dead plant and animal matter. humus hyo͞o´məs , organic matter that has decayed to a relatively stable, amorphous state. Mollisol, one of the 12 soil orders in the U.S. Soil Taxonomy. There he would find the following definition: “Humus, black-brown matter in the topsoil, is produced by the putrefaction of vegetable and animal matter. It is also a key component of ocean water, dystrophic lakes, and upland streams. Humus is rich in carbon and is generally acidic as a result of its humic acid content. It is organic because of accumulation of carbon and is hence dark in colour. 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. Definition - What does Humic Acid mean? Keywords: Soil horizon, fertility, humus, soil genesis, leaching, degradation, erosion. In some parts of the world, windblown dust and silt blanket the land. It has very important constituents to keep … 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. 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. 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"). What is Humus? When glaciers grind rocks to a fine powder, loess can form. ... humus: Meaning and Definition of. 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 …