Great Britain was glaciated during the Pleistocene, so all British soils are quite young, less than 10,000 years old. Cranfield University divided British soils into 10 major soil groups with subdivision to 27 soilscape classifications and more than 700 types. Cranfield University defined the soils on the basis of their water or seasonal flood content, horizon (layer) development, parent material on which they developed, acidity or alkalinity, and sand, silt or clay content.
10 Major Soil Groups--Drained
The least complex group is Terrestrial Raw Soils, which are mostly unvaried parent minerals. Lithomorphic soils have a humus or peat topsoil, but the parent mineral is mostly unchanged. Pelosol soils are clay soils formed from sedimentary rocks. Brown soils are well drained and have a developed B horizon. Podzolic soils have a deep organic A horizon, an acidic B horizon from which minerals were leached, plus lower horizons. Manmade soils are created on any soil that is deeply plowed.
10 Major Soil Groups--Wet
Gley is a sticky, waterlogged soil that is mottled grayish-to-blue by lack of oxygen. Raw gley soils are wet, sticky intertidal flats. Surface water gley soils develop on Pleistocene deposits and have gleyed lower horizons under a surface of shallow humus or peat. Ground water gley soils have distinct humus or peat top soils and a deeper gley horizon caused by periodic rises in groundwater. Peat soils are acidic, organic soils developed over decomposed plants in a waterlogged environment. Peat soil's organic A horizon is minimum 16 inches deep.
27 Soilscapes--Larger Classifications
Loam soil is roughly equal parts sand, silt and clay. The soil survey identified 17.5 percent of England and Wales as "slow permeable, seasonally wet basic loams and clays" suitable for pasture and woodlands. Another 16.7 percent are "free-draining slightly acid loamy soils" suitable for pasture, woodlands and bracken (fern) or gorse (low shrubs). Pasture and woodland soils also cover 9.4 percent "slightly acid loams and clays with impeded drainage" and 8.2 percent "slow permeable seasonally wet acid loams and clays."
"Shallow, lime-rich soils over chalk or limestone" as outcrops or under pastures or woodlands are 6 percent of British soils. "Freely draining acid loam soil over rock" are 5.4 percent and can be found on steep upland pastures and dry heath or moor, bracken, gorse and oak woodland. "Lime-rich loams and clays, impeded drainage" is found under pastures and ancient woodland and in some wetter areas and is 4.5 percent. Grass moor and heather with bog communities are found on the 3.6 percent "peaty slowly permeable wet very acid upland soils."
The remaining 30 percent of British soils are small divisions ranging from "freely drained lime-rich loamy soils" at 3.2 percent to "raised peat bog soils" at 0.3 percent, and beyond that to quarry sites and standing water. "Blanket bog peat soils" of wet heather moor and bog communities are 2.2 percent. "Sand due soils" are 0.3 percent. "Naturally very wet sandy and loamy soils" of mixed dry and lowland heath communities are 1.7 percent.