Soil Site Reporter

Soil Associations

1013a CROWDY 1

Soil and site characteristics
Thick very acid amorphous raw peat soils. Perennially wet. Some slowly permeable loamy soils with wet peaty surface horizons. Hagged and eroded in places.

Blanket and basin peat
Cropping and Land Use
Wet moorland and wetland habitats of poor and moderate grazing value.

Component soil series

Subgroup Series name Percentage WRB 2006 link
10.13 CROWDY 65% Ombric Sapric Histosols
7.21 WILCOCKS 15% Dystric Histic Stagnosols
6.54 HAFREN 10% Endoskeletic Histic Stagnic Albic Podzols
Covers 213 km2 in England and Wales

Soilscapes Classification
Blanket bog peat soils

1013a CROWDY 1

Detailed Description

Amorphous raw peat soils of the Crowdy series (Staines 1976) dominate this association with stagnopodzols belonging to the Hafren series and stagnohumic gley soils of the Wilcocks series. The association covers 240 kmĀ² on plateaux, gentle slopes and basins in the uplands of mid- and north Wales. Some fibrous peat soils of the Winter Hill series are included as well as thin peaty soils over rock belonging to the Hepste series (Clayden and Hollis 1984). Ironpan stagnopodzols (Hiraethog series), humic rankers (Skiddaw series) and stagnohumic gley soils on rock (Mynydd series, Clayden and Hollis 1984) are also present. The main series are briefly described and there is a key to the soils below. The association is distributed discontinuously across the main north to south watershed of Wales, generally above 350 m O.D., at the heads of streams and on saddles between the major hills. As well as the wide spreads of blanket peat, there are a few raised bogs (usually with the Welsh name Cors or Gors) such as Gors Lwyd on the watershed between the rivers Ystwyth and Elan in west Powys. In these bogs the nutrient status is even lower than in blanket bog. The more continuous mantle of blanket bog is often pierced by bare rock, especially along ridges following the strike of the rocks (Rudeforth 1970).

Soil Water Regime

The climate is cold and wet with an average annual rainfall of about 2,000 mm. Most areas are exposed or very exposed, with prevailing winds from the south-west or west maintaining high relative humidity throughout the year, and moderating to some extent the severity of winters. Deep snow is common in the winter.

Cropping and Land Use

Climate and soil wetness limit agricultural use to rough grazing, and most of the land is under unenclosed semi-natural vegetation. Cotton-grasses (Eriophorum spp) and purple moor-grass (Molinia caerulea) dominate the latter especially where water from surrounding rocks and mineral soils has carried in more nutrients. Heather moor is also extensive, particularly where the peat is hagged. The better drained stagnopodzols and rankers usually bear Nardus grassland or, where under-grazed, heather moor. Some of the thinner peats carry a wet form of Nardus grassland containing purple moor-grass. The wet regime of the soils, their low nutrient status and the risk of windthrow limit their use for forestry. Lodgepole pine and Sitka spruce are grown but yields are often only moderate or poor. The need for drainage and fertilizers, and for herbicides to suppress Calluna, increases the cost of production. The semi-natural vegetation has a low or moderate grazing value but heather moor provides sheep with a valuable bite of young Calluna shoots in the winter when little else is available. Although the main peat soils are not easily improved, piecemeal improvement is possible on the drier Skiddaw, Hiraethog and Hafren soils. Many of the hills are water-gathering grounds for large reservoirs as at Nant-y-moch and Claerwen. The available water capacity of peat soils is about twice that of mineral soils (Rudeforth and Thomasson 1970), and the peat stores large amounts of water which is released slowly into the reservoirs, sustaining flow during dry periods. During long dry spells the peat contracts, so that heavy subsequent rains pass rapidly through cracks to the streams, producing extensive networks of erosion channels and peat haggs in places. In winter when the peat has swollen and the cracks have closed, excess rainwater flows rapidly from the saturated surface into the water channels. The semi-natural vegetation communities of the rough grazings are valuable refuges for native plants and animals. In particular heather moorland, including bog heather moor, is now relatively rare internationally, so there is considerable need to conserve the best areas. Recreational use is limited because it is difficult to walk or ride over the soft wet land with its uneven and sometimes thick heathery vegetation, but the land provides a retreat for those seeking solitude in a relatively natural environment.

1013a CROWDY 1

Distribution Map

Note that the yellow shading represents a buffer to highlight the location of very small areas of the association.

Keys to component soil series


Typical Landscapes


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Citation: To use information from this web resource in your work, please cite this as follows:
Cranfield University 2024. The Soils Guide. Available: Cranfield University, UK. Last accessed 19/07/2024

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