Subgroup | Series name | Percentage | WRB 2006 link |
---|---|---|---|
5.41 | EAST KESWICK | 50% | Eutric Cambisols |
5.71 | WILDERHOPE | 20% | Endoleptic Luvisols |
3.13 | CRWBIN | 10% | Eutric Leptosols |
7 |
Freely draining slightly acid but base-rich soils |
East Keswick soils are typical brown earths in deep, well drained slightly stony fine loamy drift. They are mapped in this association with similar deep brown earths and shallower loamy soils over limestone in Dyfed, Anglesey, Clwyd and Shropshire. The association occurs on flat and gently undulating land where limestone exposures form a small but significant part of the landscape. The subsidiary typical brown earths include the reddish fine loamy Newbiggin series in drift with siliceous stones and Barkston series in drift with limestones. These fine loamy soils in deep drift cover almost half the land. Most of the remainder has soils with limestone at less than 80 cm depth. Of these, the brownish fine loamy Waltham, argillic Wilderhope and reddish Wrington series are most common. Coarse loamy soils of the Dinorben and Wick series and shallow limestone rankers of the Crwbin and humic Wetton series are minor associates. The association covers some 150 km² in Wales with a further 12 km² near the Welsh border in Shropshire. In the East Keswick series stoniness increases with depth and the lower horizons can overlie fine loamy or loose coarse loamy drift or in places a compact fragipan. Most soils in this association are near-neutral from included limestone fragments. Wilderhope series occurs over limestone where the higher pH generated by the solution of the limestone acts as a barrier to the downward movement of clay particles suspended in percolating soil water so that a characteristic argillic horizon is formed. The drift is thickest on Anglesey where soils now mapped with this association were previously mapped as the Pentraeth series (Roberts 1958). Here drift several metres thick covers the limestone. Land north of Brynteg has numerous small limestone outcrops and bedrock is at less than 1 m depth. Soils mapped here by Roberts (1958) as Gower series and his Rock Dominant areas are also included. Gower series is now classified as Crwbin series. Southwards the drift thickens and the East Keswick series predominates. There are small peat-filled basins with base-rich wetland communities of which Cors Goch is the largest. Isolated areas on Lower Limestone Shales formerly mapped as Dyfnan series and described as gley soils are now included in this association and reclassified as stagnogleyic brown earths of the Nercwys series. In Clwyd the main locality is the limestone platform north of the river Wheeler.The proportion of coarse loamy soils is higher here than elsewhere. South to Llandegla, the drift is fine loamy and the soils are similar to those on Anglesey but Manod and Brickfield series also occur. Relief is greatest where the limestone outcrop narrows and here Crwbin series and bare limestone pavements, marked by scrub of hawthorn (Crataegus monogyna) and blackthorn (Prunus spinosa), cover more of the ground. Rich limestone plant communities survive on the shallow uncultivated soils.In south-west Dyfed the soils also contain a variety of stone types, giving deep soils in which limestone is the dominant stone (Barkston series) and the reddish Newbiggin and Wrington series which contain material from the adjoining Devonian rocks. Associated argillic brown earths belong to Wilderhope, Ludford and the siltier Ston Easton series. Cultivating the shallow soils brings limestone up into the topsoil so producing calcareous profiles classed as brown rendzinas. As on Anglesey, Lower Limestone Shales are included and marked in places by stagnogleyic brown earths belonging mainly to Nercwys series
All the main soils are well drained (Wetness Class I) and artificial drainage is not necessary since excess winter rain passes readily through the soils and into widely jointed limestone. Potatoes (rooting depth 70 cm) grown in a soil 75 cm deep are not normally checked by drought while cereals which root to 120 cm in the same soil have only 75 per cent of the water normally available to them from a deeper profile. The crop-adjusted moisture deficit for grass is 100 mm at Caerwys but well below this elsewhere. For barley and potatoes at Caerwys it is 60 mm. Serious shortages of moisture can be expected in most years on the shallow Crwbin soils. Only in dry years will plants exhaust the moisture reserves of the deep soils (East Keswick, Newbiggin and Barkston series).
Fields with rock outcrops or a large proportion of Crwbin soils are of necessity under long-term grass or scrubland. The upper horizons of the deeper soils, while usually retaining adequate moisture, are easily worked. Rainfall is, however, high in west Wales and spring landwork is often restricted. Direct drilling techniques are suited to these soils and produce comparable yields to those of conventionally sown crops. In Clwyd the soils are regularly below field capacity and can usually be cultivated during the spring. The west coast has a lower frost risk than inland and in west Dyfed and Anglesey early potatoes are grown. The February cultivations required for early potatoes damage the soil and reduce yields if the land is too wet, but, near the coast, full advantage is taken of the short rain-free periods when mild temperatures and strong winds assist in drying the soil rapidly. About half of this land in Dyfed is regularly cultivated but much is ley grassland. Barley is the main arable crop while potatoes are concentrated in the most favoured areas. Elsewhere in Wales grassland is more extensive, much of it reseeded as farms convert to silage; barley is the main cereal. In Clwyd where the soils are between 150 and 250 m O.D., the frost risk is greater and the few potatoes grown are maincrop. pH is mostly neutral or slightly acid in topsoils and generally increases with depth. In general there are no nutrient deficiencies or toxicities, although on Halkyn Mountain, Clwyd, the soils are contaminated with lead, zinc, cadmium and copper from mining and smelting, and locally crops are affected. The soils are almost everywhere ideal for grassland with sufficient available water, acceptable poaching risk, good trafficability and a usable autumn flush of growth. In parts of Clwyd where the soils are shallow, yield is reduced by lack of moisture. There is little surface run-off from level ground during slurry spreading if the soils are uncompacted.
Note that the yellow shading represents a buffer to highlight the location of very small areas of the association.
Wales
Wales
Wales
Wales
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Cranfield University 2024. The Soils Guide. Available: www.landis.org.uk. Cranfield University, UK. Last accessed 08/12/2024
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