| A | B |
|---|
| Accumulation | To gather or collect |
| Arthropod | A phylum or division of the animal kingdom; includes insects, spiders, and Crustacea; characterized by a coating which serves as an external skeleton and by legs with distinct movable segments or joints. |
| Bacteria | Single-celled microorganisms; some cause human, animal, or plant diseases; others are beneficial. |
| Bedrock | Unweathered hard rock that lies directly beneath the soil layers or beneath superficial geological deposits, such as glacial drift. |
| Clay | A size term denoting particles, regardless of mineral composition, with diameter less than 2 microns. |
| Climate | The long-term average weather conditions. |
| Deposition | The addition of sediment, as by flowing water. |
| Erosion | The group of processes whereby earthy or rock material is worn away, loosened or dissolved and removed from any part of the earth’s surface. |
| Fungi | Plantlike organisms that have no chlorophyll; they get their nourishment from living or decaying organic matter. |
| Gravel | Accumulation of water-worn pebbles larger than two millimeters in diameter. |
| Ground Cover | Any vegetation that grows close to the ground, producing protection for the soil. |
| Horizon | A layer of soil, approximately parallel to the surface, having distinct characteristics produced by soil-forming processes. |
| Irrigation | The artificial application of water to soil for the purpose of increasing plant production. |
| Leaching | The removal of soluble constituents from soils or other materials by percolating water. |
| Microorganism | An organism so small that it cannot be seen clearly without the use of a microscope; a microscopic or submicroscopic organism. |
| Mottle | Color difference on a mass of moderately poorly drained soil. |
| Nematodes | Microscopic, wormlike, transparent organisms that can attack plant roots or stems to cause stunted or unhealthy growth. |
| Organic Matter | Matter found in, or produced by, living animals and plants, which contains carbon, hydrogen, oxygen, and often nitrogen and sulfur. |
| Organism | Any living individual whether plant or animal. |
| Parent Material | The horizon of weathered rock or partially weathered soil material from which the soil is formed. |
| Porosity | Refers to the extent of voids or openings in the soil that exist between soil particles and soil peds or clods. These pores hold water and air for absorption by plant roots. |
| Soil Profile | A vertical section of a soil. The section, or face of an exposure made by a cut, may exhibit with depth a succession of separate layers. |
| Rock | Mineral matter of variable composition, consolidated or unconsolidated, assembled in masses or considerable quantities in nature. |
| Sand | A group of textural classes in which the particles are finer than gravel but coarser than silt, ranging in size from 2.00 to 0.5 millimeters in diameter. |
| Silt | Small, mineral, soil particle, ranging in diameter from 0.05 to 0.002 millimeters. |
| Soil | The mineral and organic surface of the earth capable of supporting upland plants. It has been (and is being) formed by the active factors of climate and biosphere exerting their influence on passive parent material and topography over neutral time. |
| Soil Texture | The relative proportion in a soil of the various size groups of individual soil grains. |
| Topography | Slope of the land and the position on the landscape, such as the top of a hill, a hillside, or the foot of a slope. |
| Transformation | Change in form, appearance, nature, or character. |
| Translocation | To move or transfer from one place to another; cause to change location; displace. |
| Valley | An elongated depression between uplands, hills, or mountains. |
| Weathering | Atmospheric action on rock surfaces producing decomposition, disintegration, or alteration of rocks at or close to the earth’s surface. |
| Internal Drainage | The relative degree of downward movement of water in a soil. Also called permeability. |
| Loam | Soil that consists of less than 52 percent sand, 28 to 50 percent silt, and 7 to 27 percent clay, resulting in a soil texture ideal for gardening. |
| Ped | A unit of soil structure such as an aggregate, crumb, prism, block, or granule, formed by natural processes (in contrast with a clod, which is formed artificially by compression of a wet clay soil). |
| Permeability | The capacity of soil or rock for transmitting a fluid. Degree of permeability depends upon the size and shape of the pores, the size, and shape of their interconnections, and the extent of the latter. |
| Soil Profile | A vertical section of a soil. The section, or face of an exposure made by a cut, may exhibit with depth a succession of separate layers although these may not be separated by sharp lines of demarcation. |
| Soil Structure | The arrangement of primary soil particles into compound particles or aggregates that are separated from adjoining aggregates. |
| Texture | The relative portions of sand, silt, and clay particles in a mass of soil. |
| Acid | A substance containing hydrogen that dissociates to form hydrogen ions when dissolved in water. Term applied to any substance with a pH less than 7.0. |
| Alkaline | A chemical term referring to basic reaction where the pH reading is above 7, as distinguished from acidic reaction where the pH reading is below 7. |
| Base | A substance which gives off hydroxyl ions when dissolved in water, as contrasted with an acid, which gives off hydrogen ions. |
| Conductivity | The property or power of conducting heat, electricity, or sound. |
| Fertilize | To supply the necessary mineral and organic nutrients to soil or water to aid the growth and development of plants. |
| Gypsum | A mineral calcium sulfate, combined with water of hydration. In arid regions, large tonnages are used to treat sodic soils. |
| Hydrogen | A colorless, odorless, flammable gas, the lightest of the elements, that combines chemically with oxygen to form water. |
| Hydroxyl | The ion OH-. |
| Ion | An atom or a group of atoms carrying an electrical charge, which may be positive or negative. |
| Irrigation | The artificial application of water to soil for the purpose of increasing plant production. |
| Leaching | The removal of soluble constituents from soils or other materials by percolating water. |
| Lime | Strictly, calcium oxide, CaO, but, as commonly used in agricultural terminology, calcium carbonate, CaCO3, and calcium hydroxide, Ca(OH)2, are included. Agricultural lime refers to any of these compounds, with or without magnesium carbonate, which are used as amendments chiefly for acid soils. |
