All information Copyright, Cranfield University © 2018

Citation: To use information from this web resource in your work, please cite this as follows:
Cranfield University 2018. The Soils Guide. Available: www.landis.org.uk. Cranfield University, UK. Last accessed 23/10/2018

0654b LYDCOTT

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Soil and site characteristics

Loamy permeable reddish upland soils over sandstone with a wet peaty surface horizon and bleached subsurface horizon. Some soils have a thin ironpan. Rock and scree locally.

Geology

Devonian reddish sandstone

Cropping and Land Use

Wet moorland habitats of poor and moderate grazing value; coniferous woodland; recreation; military use.

Component soil series

Subgroup Series name Percentage WRB 2006 link
6.54 LYDCOTT 40% Endoskeletic Histic Stagnic Albic Podzols
6.51 BURCOMBE 20% Placic Endoskeletic Umbric Stagnic Albic Podzols
7.21 BEACON 20% Endoleptic Albic Histic Stagnosols
7.21 WENALLT 10% Chromic Dystric Histic Stagnosols

Covers 289 km2 in England and Wales

Soilscapes Classification

16
Very acid loamy upland soils with a wet peaty surface

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0654b LYDCOTT

Detailed Description

The Lydcott association is mapped on hills above 300 m O.D. over the Old Red Sandstone in south Wales and Devon and over Carboniferous rocks in the southern Pennines. Lydcott series, which belongs to the ferric stagnopodzols, predominates, with ancillary ironpan stagnopodzols, Burcombe series, and cambic stagnohumic gley soils, Beacon and Wenallt series. The soils are extremely acid with peaty tops ranging in thickness from 5 to 40 cm, the thinner peat occurring on the steeper slopes. Below the peaty surface layer is a grey, strongly leached and often very stony horizon with evidence of gleying. At this depth some Lydcott profiles have weak irregular concentrations of iron coating prismatic peds, whereas Burcombe soils have an ironpan several millimetres thick at the base of the leached horizon. Ironpans are rarely continuous and disappear and reappear over distances of a few metres. The subsoils of Lydcott and Burcombe series are generally freely draining and often brightly coloured. They closely resemble the reddish subsoils of Milford and Whitcott series on adjacent steep slopes, suggesting that the stagnopodzols developed by superficial modifications of these soils following the spread of heath since Neolithic times. Most of the soils overlie very stony sandstone Head or bedrock between 40 and 80 cm depth. Beacon series resembles the stagnopodzols in having a peaty topsoil over a gleyed subsurface horizon depleted of iron, but the underlying horizons are also gleyed, merging with rock debris at 40 to 80 cm depth. Wenallt series is similar to the Beacon series but is in thick drift. The Lydcott series is the most common overall but proportions of Burcombe and Beacon series vary considerably and either may be dominant locally. Lydcott series occupies most of the steep slopes and convex sites, but it is mixed with Burcombe and Beacon series on gentle slopes and the soil pattern is frequently complex. Locally also there are small boggy depressions with thick peat (Crowdy series) among the wet Wenallt soils. Larkbarrow soils are rare in Wales.

In Devon and Somerset these soils occur on higher ground in Exmoor Forest, on Dunkery and Winsford Hills and on Molland and Withypool Commons. The Lydcott series is the most common overall but proportions of Burcombe and Beacon series vary considerably and either may be dominant locally. Lydcott series occupies most of the steep slopes and convex sites, but it is mixed with Burcombe and Beacon series on gentle slopes and the soil pattern is frequently complex. Locally also there are small boggy depressions with thick peat of the Crowdy series among the wet Wenallt soils. Ferric podzols belonging to the Larkbarrow series occur sporadically, usually on steep slopes and under patches of dry heathy vegetation.


Soil Water Regime

The water regime of these soils is complicated by the presence of the contrasting horizons. Water is held in the surface horizons of Lydcott, Beacon and Burcombe soils, the peat acting as a sponge so that they are seasonally waterlogged even though the subsoils drain freely (Wetness Class III or IV). Where strongly formed, the ironpan also impedes water movement. Wenallt series in slowly permeable thick drift on the lower ground, is naturally wetter (Wetness Class V). Rainwater passes rapidly into streams and rivers when the upper horizons are already saturated, particularly in winter.

Cropping and Land Use

The climate is wet, cold and exposed so the land is mostly under rough grazing with bilberry heath and moist heather moor although, in places, swards dominated by mat-grass and purple moor-grass have been established following grazing and burning. The proportion of purple moor-grass varies considerably but it is most common on Beacon and Burcombe soils, becoming rare on the drier Lydcott series where the peaty surface is thin. Relative grazing value is poor to moderate, the grassland providing better grazing than the heather. Most of the land has never been cultivated but the soils would respond well to improvement using surface treatments developed at Pwllpeiran Experimental Husbandry Farm in mid-Wales on similar Hafren soils. This involves flail mowing and burning to eliminate the mat of dead vegetation followed by surface rotavation and reseeding, with large additions of lime, slag and nitrogen. The poaching risk is great, however, owing to the large retained water capacity of the peaty topsoils and the high rainfall. For afforestation, sites are deep ploughed to mix the peat and upper mineral horizons and to break any ironpan. This improves aeration and encourages deep rooting, while facilitating movement of water along the furrows into deep drains. Sitka spruce is the preferred species but tree growth may be poor or checked where heather is present unless it is suppressed with herbicide. Scots pine competes better than Sitka spruce on the heathery land. Much of the association is in the Brecon Beacons National Park and there are a number of nature reserves and sites of Special Scientific Interest. Military training and hill-walking are other important activities. These often conflicting land uses have caused some dispute between those concerned with farming, forestry, conservation and recreation.

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0654b LYDCOTT

Typical Landscapes

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All information Copyright, Cranfield University © 2018

Citation: To use information from this web resource in your work, please cite this as follows:
Cranfield University 2018. The Soils Guide. Available: www.landis.org.uk. Cranfield University, UK. Last accessed 23/10/2018