All information Copyright, Cranfield University © 2017

Citation: To use information from this web resource in your work, please cite this as follows:
Cranfield University 2017. The Soils Guide. Available: www.landis.org.uk. Cranfield University, UK. Last accessed 21/10/2017

0712d HALLSWORTH 1

« 0654a HAFREN Associations Soilsguide Home 0712e HALLSWORTH 2 »

Soil and site characteristics

Slowly permeable seasonally waterlogged clayey soils.

Geology

Drift from Palaeozoic shale

Cropping and Land Use

Permanent grassland, stock rearing and dairying; some coniferous and deciduous woodland and wet moorland habitats.

Component soil series

Subgroup Series name Percentage WRB 2006 link
7.12 HALLSWORTH 60% Clayic Eutric Stagnosols
7.12 TEDBURN 15% Clayic Eutric Stagnosols

Covers 336 km2 in England and Wales

Soilscapes Classification

17
Slowly permeable seasonally wet acid loamy and clayey soils

Top

0712d HALLSWORTH 1

Detailed Description

This is an association mainly of pelo-stagnogley soils, belonging to Hallsworth and Tedburn series, which are slowly permeable clayey soils, over shales and shaly Head. Their topsoils are mottled dark grey or greyish brown and overlie strongly gleyed, grey and rusty mottled clay subsoils. The association is mapped in Devon and Cornwall on Carboniferous and Devonian shales and in mid-Wales near Llandrindod Wells on Ordovician shales. It commonly occupies gentle footslopes and basins, though in places it extends onto broad ridge crests. The two main soils are very similar, Tedburn series being distinguished from Hallsworth series only by having shale or shaly Head within 80 cm depth. Included in the association are small areas of Dale, Cegin, Greyland and Onecote series. The association occurs in Powys over Ordovician Llanvirn shales and derived shaly Head at altitudes of 200 to 300 m O.D. The dominant Hallsworth soils are associated with fine loamy soils of the Greyland and Brickfield series. Shallower Dale and Tedburn soils are rare. Occasional outcrops of tuffs and tuffaceous shales of the Llandrindod Wells inlier give brown podzolic soils of the Malvern series, as at Llansantfraed-in-Elwell. The climate is cold and wet with an average annual rainfall of about 1100 mm.

In mid-Devon and north Cornwall on the shaly Crackington Formation both the deep and shallower soils were formerly mapped as Tedburn series. On Devonian slates, near Newton Abbot, there are more patchy occurrences of the association which was mapped as Pulsford series. Tedburn or Dale series with shaly rubble within 80 cm depth are most common in strongly dissected landscapes, as near Exeter, and on localized convexities. In Hallsworth and Tedburn soils, clay content increases from the surface into the subsoil, decreasing below about 60 cm depth. Greyland, Brickfield and Cegin series all have very limited distribution. On convex brows stonier soils than usual may mark harder rock bands in the shale. Onecote soils with humose topsoils are most common west of Okehampton where rainfall is greatest. Their occurrence east of Holsworthy and north-east of Launceston probably indicates the once widespread distribution of moorland and heath, small remnants of which have survived reclamation and enclosure. The physiographically controlled patterns of soils in this area were demonstrated by Clayden. These relationships are repeated widely between Exeter and Bude Bay. Small inclusions, usually under 100 ha, of Halstow and Denbigh soils occur within the association which is distinguished from the Hallsworth 2 association to the north, by its smaller content of loamy and silty soils.


Soil Water Regime

Where undrained, these soils are usually waterlogged for long periods in the growing season (Wetness Class V) because their subsoils are slowly permeable. Drainage achieves some improvement (Wetness Class IV). Excess winter rainfall flows laterally over the saturated soil giving rapid run-off. Moisture deficits are small and droughtiness rarely restricts crop growth.

Cropping and Land Use

These soils are ill-suited to regular cultivation even where drained. In most years they are unworkable in spring or autumn because they retain water above their plastic limit at most times. Even summer cultivation for reseeding grassland can be delayed by wet weather. In drying conditions the soils remain friable and easily worked for only a short period, changing within a few days from wet and plastic to dry and very hard. Grassland yields well under careful management as growth is little restricted by droughtiness. However, wetness makes them very susceptible to poaching, not only in spring and autumn but also in summer during spells of wet weather. Where grazing is ill-timed pastures degenerate through poaching and compaction. The widespread rushy pastures are often associated with low density, uncontrolled grazing. Liver fluke can also affect stock where the land lies wet. Some of the land is managed as coniferous woodland. Shallow cultivation and a skeleton drainage system is recommended prior to planting by Pyatt (1977), and application of phosphorus fertilizer prevents the usual check in growth after establishment. On exposed sites, mature trees commonly suffer windthrow as they root shallowly over the dense, coarsely structured and usually wet subsoil. Sitka spruce is widely planted as it is the species most able to thrive on these difficult soils. Elsewhere, unmanaged deciduous woodland, scrub, moor and heath have little economic value but provide game cover and refuges for wildlife.

Top

0712d HALLSWORTH 1

Typical Landscapes

Top

All information Copyright, Cranfield University © 2017

Citation: To use information from this web resource in your work, please cite this as follows:
Cranfield University 2017. The Soils Guide. Available: www.landis.org.uk. Cranfield University, UK. Last accessed 21/10/2017