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Ameliorant |
soil improvers i.e. lime, dolomite, gypsum, trace elements etc |
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Acid soil |
Soil with a reaction below pH7 (having more hydrogen ions over hydroxyl ions) |
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Aeration |
When air in the soil is replaced by air from the atmosphere |
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Aggregates |
groups of particles of sand, silt clay and humus within the soil held in a single unit as a clod, crumb, block or prism |
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Agronomy |
The science of soil management and crop production |
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Air-dry |
When the soil is as dry as the surrounding air making it impervious to water |
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Alkaline soil |
soil that has a pH value of greater then pH7 |
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Alluvial soils |
Soils of a recent geological age made up of sand, silt and mud that have been deposited by rivers or floods |
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Clay soils |
Soil material containing more than 40% clay less than 45% sand and less than 40% silt |
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Clay pan |
Compacted area whish is slowly permeable to water can be of variable thickness with a sub-soil of vastly higher clay content then the soil above it; usually hard when dry and sticky when wet |
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Clod |
A compact, easily broken up mass of soil that has usually been created through the use of tillage on overly wet or dry soil |
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Crumbs |
soft, porous structures of soil that are naturally occurring and about 1 to 5mm in diameter |
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Crust |
a surface layer on soil that can vary in thickness from a few millimetres to several centimetres and is harder and more brittle when dry then the underlying soil. |
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Dolomite |
a limestone source having significant magnesium content |
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Erosion |
the removal of the land surface by wind, water, corrosion or gravity |
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Friable |
refers to the a soil moisture consistency that crumbles when handled |
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Green Manure |
a crop that is ploughed into the ground while still green to improve the soil. |
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Heavy Soil |
A soil with a high content of clay or one that is difficult to cultivate without high powered equipment |
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Light Soil |
Sandy soils which are easy to cultivate |
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Loam |
refers to a specific textural class of soils that have prescribed amounts of clay, silt and sand |
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Organic soil |
a soil that contains a high (more than 20%) amount of organic matter |
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Ped |
a unit of soil structure such as a crumb, block, aggregate prism or granule that has been formed by natural processes. |
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Particles |
sand, silt, clay and humus are all individual particles within the soil |
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Percolation |
the movement, downwards of water through the soil |
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pH |
measure of alkalinity or acidity of the soil |
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Porosity |
the amount of air passages (pores) in the soil |
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Saline soils |
soil containing soluble salts in a concentration sufficient to weaken (or impair) plant growth. |
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Sod |
the top 3-7cm of soil held together by grass or legume roots |
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Soil Structure |
the arrangement of primary soil particles into peds etc. within the soil, (the manner in which the smaller particles i.e. sand, silt, clay are aggregated. |
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Soil Texture |
the relative percentages of sand, silt and clay in the soil |
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Subsoil |
that part of the soil that lies below the topsoil but above the bedrock |
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Tension, soil moisture |
The attraction with which water is held to soil particles; negative pressure of water in soil |
