| Organic Matter | Soil Texture | |||
|---|---|---|---|---|
| % | Loamy Sand | Sandy Loam | Loam | Silt Loam |
| Less than 0.5% | Very Low | Very Low | Very Low | Very Low |
| 0.5 to 1.0% | Low | Very Low | Very Low | Very Low |
| 1.0 to 1.5% | Medium | Low | Very Low | Very Low |
| 1.5 to 2.0% | High | Medium | Low | Low |
| 2.0 to 2.5% | Very High | High | Medium | Low |
| 2.5 to 3.0% | Very High | Very High | Medium | Medium |
| 3.0 to 3.5% | Very High | Very High | High | Medium |
| 3.5 to 4.0% | Very High | Very High | High | Medium |
| 4.0 to 5.0% | Very High | Very High | Very High | High |
| More than 5% | Very High | Very High | Very High | Very High |
Notes
Soil textures finer than those listed (clay loams and clays) can be evaluated using the "silt loam" column.
Organic matter values are expressed as percentage by weight basis. The value accounts for soil humus and easily oxidized organic fractions of the soil but may not include unreactive fractions.
Although organic matter would include anything organically-derived, samples are sieved to remove gravel (>2mm), which may also remove particulate organic matter as well, including sticks and roots.
Organic matter content is a dynamic soil property, strongly influenced by management and affected by environmental conditions as microorganisms continue to decompose the organic matter and release nutrients.
While organic matter is a valuable soil component for chemical, physical, and biological reasons, amending soils to organic matter content greater than 10% is not recommended for general use as plant growth media.