Term
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Definition
| Large (noncapillary) pores that normally drain free of liquid water because of gravitational drainage and fill up with air. |
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Term
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Definition
| Function of soil to hold plant firmly in place. |
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Term
Best Management Practice
(BMP) |
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Definition
| A practice recommended to reduce environmental impact of such activities as farming or land development, that is practical for the practitioner. Applied to such land management practices as soil conservation, manure handling, stormwater management, and others. |
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Term
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Definition
| Removal of carbon dioxide from the atmosphere and its deposition in some sink. Soil organic matter, especially in Gelisols and Histosols, is a very large carbon sink. |
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Term
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Definition
| A location where, as part of the carbon cycle, carbon is trapped for a time so it does not return to the atmosphere as carbon dioxide. Examples of sinks include wood in trees, carbon dioxide dissolved in the oceans, carbonate materials, and, humus in soil and organic matter trapped in Gelisols and Histosols. |
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Term
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Definition
| Land suited or used for the purpose of raising crops. |
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Term
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Definition
| Conversion of land to desert, often caused by overgrazing, deforestation, or other disturbance. |
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Term
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Definition
| A hard subsoil layer caused by cementation by carbonates or other chemicals; limits root growth and the infiltration of water. |
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Term
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Definition
| Crops grown in nutrient solutions rather than soil. |
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Term
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Definition
| Ability of a soil to carry a load such as a roadbed or building without shifting. |
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Term
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Definition
| Large, noncapillary pores that transmit water rapidly and are important for soils to drain readily. As they drain, water is replaced with air. |
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Term
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Definition
| Small, capillary pores that transmit water slowly and hold water against gravity. They are important for the storage of water. |
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Term
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Definition
| Elements in the form of ions or molecules used in the metabolism of plants, animals, and microbes. |
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Term
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Definition
| The reaction, in the presence of chlorophyll, of carbon dioxide and water to form sugar, using light energy. |
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Term
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Definition
| Portion of soil not occupied by solid material but that is filled with air or water. |
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Term
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Definition
| Biological reaction in which carbohydrates are broken down to carbon dioxide and water with the release of energy. Opposite of photosynthesis. |
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Term
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Definition
| How much a mass of soil swells when wet and shrinks when dry; a function of the amount of swelling clays. An important engineering property of soil. |
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Term
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Definition
| Process by which air in the soil is replaced by air from the atmosphere. Related to number, size, and continuity of soil pores and to internal drainage. |
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Term
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Definition
| Gas phase of soil; space of soil not filled with solid or liquid. |
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Term
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Definition
| Loss of soil quality through such processes as erosion, salination, contamination, severe compaction, and numerous others. |
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Term
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Definition
| The arrangement of solid soil particles and soil pore spaces, which is a three-phase system of solid, liquid, and gas. |
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Term
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Definition
| Capacity of a soil to provide the needed functions for human or natural ecosystems over the long term. |
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Term
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Definition
| The liquid phase of soil, consisting of water and dissolved ions. |
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Term
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Definition
| Soil whose pores are filled with water and so are low in oxygen. Caused by high water tables, poor drainage, or excess moisture from rain, irrigation, or flooding. |
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