| soil matrix | The portion of a given soil having the dominant colour, in most cases, the matrix will be the portion of the soil having more than 50 percent of the same colour. (09 Oct 1997) |
|---|---|
| soil microbiology | The presence of bacteria, viruses, and fungi in the soil. This term is not restricted to pathogenic organisms. (12 Dec 1998) |
| soil permeability | The ease with which gases, liquids or plant roots penetrate or pass through a layer of soil. (09 Oct 1997) |
| soil phase | A subdivision of a soil series having features (for example, slope, surface texture, thickness and stoniness) that affect the use and management of the soil, but which do not vary sufficiently to differentiate it as a separate series. (09 Oct 1997) |
| soil pollutants | Substances which pollute the soil. Use for soil pollutants in general or for which there is no specific heading. (12 Dec 1998) |
| soil pollutants, radioactive | Pollutants, present in soil, which exhibit radioactivity. (12 Dec 1998) |
| soil pore | An area within soil occupied by either air or water, resulting from the arrangement of individual soil particles. (09 Oct 1997) |
| soil profile | A vertical section of the soil through all its horizons and extending into the parent material. (09 Oct 1997) |
| soil series | A group of soils having horizons similar in differentiating characteristics and arrangements in the soil profile, except for texture of the surface layer. (09 Oct 1997) |
| soil structure | The combination or arrangement of primary soil particles into secondary particles, units or peds. (09 Oct 1997) |
| soil suborder | Second highest taxonomic level of the current U.S. Soil classification system. (09 Oct 1997) |
| soil surface | The upper limits of the soil profile, for mineral soils, the upper limits of the highest mineral horizon (A-horizon), for organic soils, the upper limit of undecomposed organic matter. (09 Oct 1997) |
| soil texture | The relative proportions of the various sizes of particles (silt, sand and clay) in a soil. (09 Oct 1997) |
| soil value | The relative lightness or intensity of colour, approximately a function of the square root of the total amount of light, one of the three variables of colour. (09 Oct 1997) |
| somewhat poorly drained soil | <botany> A condition in which water is removed slowly enough that the soil is wet for significant periods during the growing season. (04 Mar 1998) |