Know Soil, Know Life Terms

Practices by which a crop is planted directly into the soil with no primary or secondary tillage. The surface residue is left virtually undisturbed except where the seed is planted.

An element essential to living organisms.

A bog, soil or vegetation that receives all moisture from atmospheric sources such as precipitation rather than groundwater, springs, or rivers.

Soil materials that are saturated with water and have 174 g kg-1 or more organic carbon if the mineral fraction has 500 g kg-1 or more clay, or 116 g kg-1 organic carbon if the mineral fraction has no clay, or has proportional intermediate contents, or if never saturated with water, have 203 g kg-1 or more organic carbon.

Very weathered soils of tropical and subtropical environments—Puerto Rico and Hawaii and other tropical areas such as Brazil and Southeast Asia.

Any disease-producing agent, especially a virus, bacterium, or other microorganism.

A unit of soil structure such as a block, column, granule, plate, or prism, formed by natural processes (in contrast with a clod, which is formed artificially).

That shell or layer of the earth in which soil-forming processes occur. It is where the lithosphere, biosphere, hydrosphere and atmosphere intersect (the soil).

An agricultural system or method that seeks to integrate human activity with natural surroundings so as to create highly efficient self-sustaining ecosystems.

Permanently frozen subsoil, occurring throughout the polar regions and locally in perennially frigid areas.

(i) The ease with which gases, liquids, or plant roots penetrate or pass through a bulk mass of soil or a layer of soil. Since different soil horizons vary in permeability, the particular horizon under question should be designated. (ii) The property of a porous medium itself that expresses the ease with which gases, liquids, or other substances can flow through it, and is the same as intrinsic permeability k.

A bioremediation process the uses plants to remove or neutralize contaminants from polluted soil or water.

single identifiable source of air or water pollution and that has negligible extent.

The volume of pores in a soil sample (nonsolid volume) divided by the bulk volume of the sample.

Specific cations and anions combine to form a compound.