Humus

This is hummus.. Not to be confused with humus

This is humus!

Humus is a type of soil created from decaying plants and organisms. Coined by a french soil scientist, Muller, the name is derived from the latin word "soil". Humus is difficult to describe and has yet to be fully understood.

Description

Humus is a a non living organic matter in soil that is derived from microbial decomposition of plant and animal substances. [6] Humus is dark colored and consists of approximately 60% carbon, 6% nitrogen and small amounts of sulfur and phosphorus. the color of humus is highly influenced by humus by the variation of the climate. There is less colouration in tropics and subtropics and more intense colouration in humid-temperate zones. In agricultural terms, humus can be described as well aged compost. Organic matter decomposes molecules into smaller molecules by microorganisms in the soil. Most of the chemicals in this organic matter can be extracted by microorganisms and can be shared with other beings within the soil. Humus has a wide variety of decay (ex. peatmoss, gradd, leaf compost, wood chips, decaryed sawdust, garden waste, etc). [3] Humus has higher water adsorptive capacity than clay. it has a complex structure and has two main structural units; phenolic nature and nitrogen compounds. Humus also has low plasticity and cohesion.

Formations of humus

Mor

Mor is generally found in coniferous forests or mixed-wood forests. it is also associated with acidic conditions. Mor comes from decomposing organic matter that lies on the surface of the soil. Fungi, earthworms, and small arthropods are some common organisms that decay into mor. Mor usually contains a low mineral content. The biological activity is relatively low, preventing decomposition of the organic matter. Mor has a slow transformation and accumulation process of plant residue. [4]

Moder

Moder is the transitional form of humus. it lies between mull and moder. This type of humus is moderately humified and has characteristics of both mor and mull. Moder can be found where mor or mull are not generally favorable. [5]

Mull

Mull can be found in hardwood forests, deciduous forests, or grasslands in warm, humic climates. Unlike mor, the pH in this humus formation is much higher and larger insects are more abundant. mull is subject to rapid decomposition and is well mixed with minerals [5]

Humification

Humification is the process of formation of humic substances decomsed from plant remains. This is a reults from oxidation by addition of oxygen from oxygenated water and lowering the groundwater tbale, heat and exposure, and pH values of water in the peat. Fungi and microbes attack lignin that bings cells, fibers, and vessels of wood and converts them into humic substances. Kodel-Knabner has summarized the formation of humus as selective preservation of plant and microbial polymers, direct transformation and microbial resynthesis. Darker colors signify strong humification and lighter colors point to wetter periods and less humification. Humification accelerates at high temperatures. [7]

Benefits of Humus

- Humus absorbs moisture, therefore it raises the temperature of the soil and can maintain its heat. [1] This can prevent the roots of plants form frosting during cold weather events. - Humus holds onto nutrients and can prevent them from leaching.

- Humus can absorb moisture which can help soil during dry weather events.

- Since humus can retain nutrients, this allows plants and organisms to thrive in the soil. Humus feeds the population of organisms living in it.

- Humus can protect the soil from extreme temperatures. It also plays a huge role in soil fertility.

- Humus' biochemical structure allows it to buffer excessive acid or alkaline soil conditions. This prevents toxic substances from entering the ecosystem.

- Humus supports the growth of a very important organism called mycorrihizal fungi. This fungi has a symbiotic relationship with many plants and helps bind the soil particles together to form a sturdy soil structure. [2]

- Humus is a source of nutrients for microbes, microscopic organisms with a vast number of species

References

1. Britannica, T. E. (2015, July 27). Humus. Retrieved from https://www.britannica.com/science/humus-soil-component

2. What Role Does Humus Play in Soil Fertility? (2018, March 15). Retrieved from https://greentumble.com/what-role-does-humus-play-in-soil-fertility/

3. What is humus? - the secrete to great soil. (2017, March 22). Retrieved from https://www.gardenmyths.com/what-is-humus/

4. (n.d.). Retrieved from http://karnet.up.wroc.pl/~weber/typy2.htm

5. (n.d.). Retrieved from http://forestfloor.soilweb.ca/definitions/humus-forms/

6. National Geographic Society. (2012, October 09). Humus. Retrieved from https://www.nationalgeographic.org/encyclopedia/humus/

7. Humification. (n.d.). Retrieved from https://www.sciencedirect.com/topics/earth-and-planetary-sciences/humification