GENERAL GEOLOGY

Detailed explanation-1: -The thick brown or black substance that remains after most of the organic litter has decomposed is called humus. Earthworms often help mix humus with minerals in the soil. Humus contains many useful nutrients for healthy soil. One of the most important is nitrogen.

Detailed explanation-2: -Humus greatly increases soil fertility and overall health, and thus plant growth, thanks to the presence of beneficial nutrients like nitrogen and carbon. (Humus has a carbon to nitrogen ratio of 10:1.)

Detailed explanation-3: -Humus allows soil organisms to feed and reproduce, and is often described as the “life-force” of the soil. The process that converts soil organic matter into humus feeds the population of microorganisms and other creatures in the soil, and thus maintains high and healthy levels of soil life.

Detailed explanation-4: -Decomposing organisms also create organic acids that increase the rate of weathering and soil formation. Bacteria in the soil change atmospheric nitrogen into nitrates. The decayed remains of plant and animal life are called humus, which is an extremely important part of the soil. Humus coats the mineral grains.

Detailed explanation-5: -Humus is the organic matter of soil, consisting of decomposed plants and animals. Silt, sand, and clay soils all contain humus.