GENERAL GEOLOGY

Detailed explanation-1: -humus, nonliving, finely divided organic matter in soil, derived from microbial decomposition of plant and animal substances. Humus, which ranges in colour from brown to black, consists of about 60 percent carbon, 6 percent nitrogen, and smaller amounts of phosphorus and sulfur.

Detailed explanation-2: -As the decomposition of dead plant matter and animals occurs, nutrients held within the plant matter or animal are released into the soil. This end result of the decomposition is known as humus. This humus represents up to 1 to 5% of the dry weight of the soil.

Detailed explanation-3: -Humus is dark, organic material that forms in soil when plant and animal matter decays. When plants drop leaves, twigs, and other material to the ground, it piles up. This material is called leaf litter. When animals die, their remains add to the litter. Over time, all this litter decomposes.

Detailed explanation-4: -Soil organic matter: What is it and why is it important? Soil organic matter (SOM) is the portion of soil that is composed of living and dead things in various states of decomposition, such as plant roots and microbes.

Detailed explanation-5: -What is organic matter? Organic materials are the fraction of the soil that includes approximately 5% of living organisms, 10% crop residues, 33-50% decomposing O.M. (the active fraction) and 33-50% stable O.M. (humus) by weight (USDA-NRCS, 2014).