Soil organic matter (SOM) is the organic matter component of soil. It can be divided into three general pools: living biomass of microorganisms, fresh and partially decomposed residues, and humus: the well-decomposed organic matter and highly stable organic material. Surface litter is generally not included as part of soil organic matter.
According to Troeh and Thompson's Soils and Soil Fertility, "Organic matter constitutes from 1 to 6% of the topsoil weight of most upland soils. Topsoils with less than 1% organic matter are mostly limited to desert areas. At the other extreme, the organic matter content of soils in low wet areas may be as high as 90% of more. Soils with more than 12-18% organic carbon (approximately 20-30% organic matter) are called organic soils."
Famous quotes containing the words soil, organic and/or matter:
“This fair homestead has fallen to us, and how little have we done to improve it, how little have we cleared and hedged and ditched! We are too inclined to go hence to a “better land,” without lifting a finger, as our farmers are moving to the Ohio soil; but would it not be more heroic and faithful to till and redeem this New England soil of the world?”
—Henry David Thoreau (1817–1862)
“And what if all of animated nature
Be but organic Harps diversely framed,
That tremble into thought, as o’er them sweeps
Plastic and vast, one intellectual breeze,
At once the Soul of each, and God of all?”
—Samuel Taylor Coleridge (1772–1834)
“The whole matter revolves around the self-respect of my people. How much satisfaction can I get from a court order for somebody to associate with me who does not wish me near them?”
—Zora Neale Hurston (1891–1960)