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A stone layer on which a surface carpet might be laid, typically with a shockpad; or an engineered layer is laid. A base layer is also termed a sub-base. However, if there are two distinct layers of stone present in the construction then the upper of the two layers would be termed the base layer and the lower one being termed the sub-base layer.

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A process which causes weakening and disintegration of rocks through the actions of plants, micro-organisms and animals. Biological weathering may be the start of a process but the actual weathering which occurs is physical or chemical weathering. Plant roots grow into small cracks within rocks and soil aggregates, expanding the crack as they grow, and this forces them apart. Animals can also burrow and scrape away in soils and weakened rocks, leading to more rapid breakdown of the material. Plants also exude weak acids from their roots, which can gradually dissolve and weaken rocks, l

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A layer which separates two otherwise adjoining layers. A blinding layer is typically used in a drainage system where a finer topsoil or sand overlies a coarser gravel layer. Without an intermediate blinding layer covering the gravel, the topsoil would just wash down into the gravel layer. This term is also referred to as Intermediate Layer, or Choke Layer.

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A soil ped, which is cube like having an angular to sub-angular type structure. It is common in subsoils, especially of high clay content, which can readily lock together reducing drainage. Where a loose blocky structure exists, especially beneath a good granular topsoil, this can result in good drainage and rooting conditions.

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A type of soil which is usually fertile, having adequate supplies of phosphorus and potassium, as well as organic matter to aid cation exchange capacity, and is common in grassland and deciduous woodlands. Humus will typically be of the mull type, but the moder type, which is less decomposed due to reduced soil fauna and micro-organism activity, will also be present in some cases. The A horizon will typically be a dark brown colour, having good soil structure, abundant micro-organism activity, be slightly acidic to neutral, and have good soil aeration for root growth. Earthworm activity ca

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The ability of a soil to resist changes to its soil pH. It is measured by determining the amount of acidic material (such as sulphur) required to raise the pH of a soil, or the amount of base or alkaline material, such as lime (calcium carbonate) to lower the pH of a soil. The unit amount is usually given as one kg, so for example, to lower a soil with a pH of 7.0 to a pH of 6.2 might require the addition and incorporation of x kg of sulphur. Sandy soils have a lower buffering capacity than a clay loam soil. The main reason being that pH measures the concentration of hydrogen ions within a

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A clay loam with a typical clay content of 50%-60% which is used in South Africa, Australia and countries where hot dry conditions can adequately dry out this type of clay loam on a cricket pitch.

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A system of drainage which has channels cut into a surface and which may connect to a piped drainage system. These channels will typically be narrow sand-slits, sand-gravel slits, or sand-bands. Water can readily bypass a relatively poorly drained soil root zone by the more rapid drainage opportunity offered by the cut channels. This is also referred to as either Bypass Drainage, or a Bypass System.

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A parent material layer, which is unconsolidated having loose element of rock present. It is typically a layer in which the process of soil formation is in very early stages. The 'C' Horizon is situated below the 'B' subsoil Horizon. There will be very little organic matter and micro-organism activity, with little available nutrients. The horizon may be subject to permanent or temporary waterlogging depending on the height of a water table and closeness to rivers, in which case gleying will occur to some extent.

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A soil which usually has more than 15% Calcium Carbonate (or chalk). Calcareous soils often lack available phosphorus, as well as a deficiency of Iron and Zinc in particular.