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:
“The same soil is good for men and for trees. A man’s health requires as many acres of meadow to his prospect as his farm does loads of muck.”
—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 stern hand of fate has scourged us to an elevation where we can see the great everlasting things which matter for a nation—the great peaks we had forgotten, of Honour, Duty, Patriotism, and, clad in glittering white, the great pinnacle of Sacrifice pointing like a rugged finger to Heaven.”
—David Lloyd George (1863–1945)