| A | B |
|---|
| adsorption | bonding of an ion to a solid surface, usually temporarily |
| anion exchange capacity | total sum of the number of exchangeable anions a soil can adsorb |
| cation exchange | exchange between a cation in solution and one adsorbed on a soil colloid |
| cation exchange capacity | total number of exchangeable cations a soil can adsorb |
| Colloid | a very thin particle capable of being suspended in water without settling out rapidly |
| diffusion | flow of matter through a liquid or gas by the random movement of molecules, caused by a concentration gradient, with the ions moving from more to less concentrated |
| essential elements | an element needed by plants for proper growth and reproduction |
| exchangeable bases | a cation, excluding hydrogen and aluminum, held on cation exchange sites that can be easily replaced by another cation |
| expanding clays | clays that expand greatly upon adsorption of interlayer water and shrink considerately upon drying |
| hydroponics | the culture of plants in nutrients solutions rather than soil |
| isomorphous substitution | Replacement of one atom by another of similar size in a crystal lattice. May result in a charge if the atom has a different charge than the one replaced |
| luxury consumption | absorption by plants of more nutrients, especially K, than they need at the time. |
| macronutrients | an essential element used in large amounts by plants, including N, P, K, Ca, Mg, S |
| mass action | law describing the principal of chemical equilibrium and the math description of this law called equilibrium constant expression |
| mass flow | movement of nutrients by movement of soil water |
| micelle | an individual particle of silicate clay |
| micronutrient | essential element used in small quantities by plants |
| nonexchangeable ions | applied to an ion so strongly adsorbed to a soil colloid that it is not normally available to be exchanged with ions in the soil solution |
| oxide clays (sesquioxide) | finely divided particles of iron and aluminum oxides, most common in soils of warm, humid regions |
| percent base saturation | percentage of the cation exchange sites filled with exchangeable bases |
| primary macronutrient | three macronutrients (N,P,K) needed to be added to the soil in the greatest amounts for good crop growth |
| root interception | root surfaces find and adsorb nutrients directly from the surface of soil colloids |
| secondary macronutrient | macronutrients used less often as fertilizers than the primary elements (Ca, Mg, S) |
| silicate clays | clays formed by association of structural units based on silica sheets and alumina sheets |
| soil fertility | ability of a soil to supply the elements needed for plant growth |
| soil solution | the liquid phase of soil, consisting of water and dissolved ions |
| trace element(micronutrient) | essential elements used in small quantities by plants |
