Sustainable Soil Management
Glossary
S
SALINITY. An index of concentration of dissolved salts in the soil.
SALINIZATION. A buildup of salts in soils to the point that they destroy the soil’s physical and chemical properties and plants are not able to take up water due to the high salt concentration; often associated with improper irrigation.
SECONDARY NUTRIENTS. Those macronutrients (calcium, magnesium, and sulfur) used less often as fertilizers than the primary elements.
SEDIMENT. Eroded soil and rock material and plant debris transported and deposited by wind or water.
SEDIMENTARY ROCK. A rock formed from materials deposited from suspension or precipitated from solution and usually being more or less consolidated. The principal sedimentary rocks are sandstones, shales, limestones, and conglomerates.
SERIES, SOIL. The soil series is a subdivision of a family in Soil Taxonomy and consists of soils that are similar in all major profile characteristics.
SHEET AND TILL EROSION. A water erosion process caused by raindrop impact on the soil surface and a thin layer of water (sheet) moving over the soil surface.
SHELTERBELT. A wind barrier of living trees and shrubs established and maintained for protection of farm fields. Syn. windbreak.
SIDEDRESS. To apply a fertilizer, pesticide, or soil amendment to one side of a growing plant, either by surface application or injection.
SODIC SOIL. Soil high in sodium and low in soluble salts.
SOIL AMENDMENT. Any material, such as lime, gypsum, sawdust, or synthetic conditioner, that is worked into the soil to make it more amenable to plant growth.
SOIL ANALYSIS. A chemical, physical, or biological procedure that estimates the plant availability of nutrients and soil quality characteristics to support plant growth.
SOIL CLASSIFICATION (Soil Taxonomy). The systematic arrangement of soils into groups or categories on the basis of their characteristics. See order; suborder; great group; subgroup; family; and series.
SOIL CONSERVATION. A combination of all management and land-use methods that safeguard the soil against depletion or deterioration caused by nature and/or humans.
SOIL DRAINAGE. The process where water is moved by gravity, either by surface channels or internal pores in the soil profile.
SOIL MAP. A map showing the distribution of soil types or other soil mapping units in relation to the prominent physical and cultural features of the Earth’s surface.
SOIL MORPHOLOGY. The physical constitution, particularly the structural properties, of a soil profile as exhibited by the kinds, thicknesses, and arrangement of the horizons in the profile, and by the texture, structure, consistence, and porosity of each horizon.
SOIL ORGANIC MATTER. The organic fraction of the soil exclusive of undecayed plant and animal residues. Often used synonymously with “humus.”
SOIL pH. The degree of acidity or alkalinity of a soil, expressed on a scale from 0 to 14, with 7.0 indicating neutrality, increasing values indicate increasing alkalinity, while decreasing values indicate increasing acidity.
SOIL PRODUCTIVITY. A measure of the soil’s ability to produce a particular crop or sequence of crops under a specific management system.
SOIL QUALITY. The capacity of a specific kind of soil to function physically, chemically and biologically, within natural or managed ecosystem boundaries, so as to maximize provisioning and regulatory ecosystem services. Often considered in relative to this capacity in the undisturbed, natural state.
SOIL REACTION. A quantitative term that describes how acidic or alkaline the soil is.
SOIL SAMPLING. Process of obtaining a representation of an area of the soil or field by collecting a portion of the soil.
SOIL SOLUTION. The aqueous liquid phase of the soil and its solutes contained in soil pores.
SOIL STRUCTURE. The combination or arrangement of primary soil particles into secondary soil particle units, or peds.
SOIL SURVEY. The examination, description, and mapping of soils of an area according to the soil classification system.
SOIL TEST LEVEL. The nutrient status of the soil, as indicated by analysis of a soil sample.
SOIL TEST RECOMMENDATION. The suggested amount of nutrients or soil amendment to be added to the soil to achieve expected crop yields.
SOIL TEXTURAL CLASS. A grouping of soil textural units based on the relative proportions of the various soil separates (sand, silt, and clay). These textural classes, listed from the coarsest to the finest in texture, are sand, loamy sand, sandy loam, loam, silt loam, silt, sandy clay loam, clay loam, silty clay loam, sandy clay, silty clay, and clay. There are several subclasses of the sand, loamy sand, and sandy loam classes based on the dominant particle size of the sand fraction (e.g., loamy fine sand, coarse sandy loam).
SOIL TEXTURE. The relative proportions of sand, silt, and clay in the soil.
SOIL WATER DEFICIT. The difference between PET and ET, representing the gap between the amount of evapotranspiration water atmospheric conditions “demand” and the amount the soil can actually supply. A measure of the limitation that water supply places on plant productivity.
SOIL WATER POTENTIAL. A measure of the difference between the free energy state of soil water and that of pure water. Technically it is defined as that amount of work that must be done per unit quantity of pure water in order to transport reversibly and isothermally an infinitesimal quantity of water from a pool of pure water, at a specified elevation and at atmospheric pressure, to the soil water (at the point under consideration). This total potential consists of gravitational, matric, and osmotic potentials.
SOLUBILITY. Amount of a substance that will dissolve in a given amount of another substance, typically water.
SOLUTE. A substance that is dissolved in another substance, thus forming a solution.
SPECIFIC GRAVITY. The ratio of the density of a mineral to the density of water at standard temperature and pressure.
SPLASH EROSION. The spattering of small soil particles caused by the impact of raindrops on very wet soils. The loosened and separated particles may or may not be subsequently removed by surface runoff.
SPODOSOLS. An order in Soil Taxonomy. Soils with subsurface illuvial accumulations of organic matter and compounds of aluminum and usually iron. These soils are formed in acid, mainly coarse-textured materials in humid and mostly cool or temperate climates.
STARTER FERTILIZER. A fertilizer applied in relatively small amounts with or near the seed at planting.
STRIP-TILL. Planting is done in a narrow strip that has been tilled and mixed, leaving the remainder of the soil surface undisturbed.
STUBLE MULCH. The stubble of crops or crop residues left essentially in place on the land as a surface cover before and during the preparation of the seedbed and at least partly during the growing of a succeeding crop.
SUBSOILING. Breaking of compact subsoils, without inverting them, with a special knife-like instrument (chisel), which is pulled through the soil at depths usually 15 to 30 inches.
SUBSURFACE BAND. To apply nutrients, pesticides, or soil amendments in narrow bands below the surface of the soil.
SUFFICIENCY LEVEL. (a) For interpretation of plant analysis: A nutrient concentration in the plant tissue above which the crop is amply supplied, and below which the crop is deficient. (b) For interpretation of soil analysis: A soil test level above which economic responses to applied fertilizers are unlikely to occur.
SURFACE BAND. To apply nutrients, pesticides, or soil amendments in narrow bands over the surface of the soil.
SURFACE BROADCAST. To apply nutrients, pesticides, or soil amendments uniformly over the surface of the soil.
SYMBYOTIC N FIXATION. Conversion of molecular nitrogen to ammonia and subsequently to organic nitrogen forms by organisms.
