Benefits of Soil Organic Matter and Humus
- The process that converts raw organic matter into humus feeds the soil population of microorganisms and other creatures, thus maintains high and healthy levels of soil life.
- The rate at which raw organic matter is converted into humus promotes (when fast) or limits (when slow) the coexistence of plants, animals, and microbes in soil.
- Effective humus and stable humus are further sources of nutrients to microbes, the former provides a readily available supply, and the latter acts as a longer-term storage reservoir.
- Decomposition of dead plant material causes complex organic compounds to be slowly oxidized (lignin-like humus) or to break down into simpler forms (sugars and amino sugars, aliphatic, and phenolic organic acids), which are further transformed into microbial biomass (microbial humus) or are reorganized, and further oxidized, into humic assemblages (fulvic and humic acids), which bind to clay minerals and metal hydroxides. There has been a long debate about the ability of plants to uptake humic substances from their root systems and to metabolize them. There is now a consensus about how humus plays a hormonal role rather than simply a nutritional role in plant physiology.
- Humus is a colloidal substance, and increases the soil's cation exchange capacity, hence its ability to store nutrients by chelation. While these nutrient cations are accessible to plants, they are held in the soil safe from being leached by rain or irrigation.
- Humus can hold the equivalent of 80–90% of its weight in moisture, and therefore increases the soil's capacity to withstand drought conditions.
- The biochemical structure of humus enables it to moderate – or buffer – excessive acid or alkaline soil conditions.
- During the humification process, microbes secrete sticky gum-like mucilages; these contribute to the crumb structure (tilth) of the soil by holding particles together, and allowing greater aeration of the soil. Toxic substances such as heavy metals, as well as excess nutrients, can be chelated (that is, bound to the complex organic molecules of humus) and so prevented from entering the wider ecosystem.
- The dark color of humus (usually black or dark brown) helps to warm up cold soils in the spring.
Read more about this topic: Humus
Famous quotes containing the words benefits of, benefits, soil, organic and/or matter:
“One of the benefits of a college education is, to show the boy its little avail.”
—Ralph Waldo Emerson (1803–1882)
“It is with benefits as with injuries in this respect, that we do not so much weigh the accidental good or evil they do us, as that which they were designed to do us.—That is, we consider no part of them so much as their intention.”
—Laurence Sterne (1713–1768)
“Have you seen but a bright lily grow
Before rude hands have touch’d it?
Have you mark’d but the fall of the snow
Before the soil hath smutch’d it?
Have you felt the wool of the beaver,
Or swan’s down ever?
Or have smelt of the bud of the brier,
Or the nard in the fire?
Or have tasted the bag of the bee?
O so white, O so soft, O so sweet is she!”
—Ben Jonson (1572–1637)
“The following general definition of an animal: a system of different organic molecules that have combined with one another, under the impulsion of a sensation similar to an obtuse and muffled sense of touch given to them by the creator of matter as a whole, until each one of them has found the most suitable position for its shape and comfort.”
—Denis Diderot (1713–1784)
“There is not the woman born who desires to eat the bread of dependence, no matter whether it be from the hand of father, husband, or brother; for any one who does so eat her bread places herself in the power of the person from whom she takes it.”
—Susan B. Anthony (1820–1906)