Soil Associations

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Soil and site characteristics

Slowly permeable seasonally waterlogged fine loamy over clayey and fine silty over clayey soils associated with similar clayey soils often with brown subsoils.

Geology

Drift over Tertiary clay

Cropping and Land Use

Permanent and short term grassland dairying; some cereals.

Component soil series

Subgroup	Series name	Percentage	WRB 2006 link
7.11	WICKHAM	60%	Eutric Luvic Planosols
7.12	DENCHWORTH	20%	Eutric Vertic Stagnosols
7.12	WINDSOR	20%	Eutric Vertic Stagnosols

Covers 1007 km² in England and Wales

Soilscapes Classification

18	Slowly permeable seasonally wet slightly acid but base-rich loamy and clayey soils

0711h WICKHAM 4

Detailed Description

This association consists of seasonally waterlogged soils with clayey slowly permeable subsurface horizons. It occurs mainly in southern England, and is extensive on gently undulating land in clay vales where the underlying Tertiary clay is thinly covered by loamy drift. The dominant soils are Wickham series, typical stagnogley soils, fine loamy or fine silty over clayey and with grey and ochreous mottles throughout. The associated Windsor and Denchworth series, are pelo-stagnogley soils, clayey to the surface and are found where the Head is very thin or absent. Both soils have grey and ochreous mottles, but Windsor soils become brownish at depth. Wickham soils are most common on gently sloping valley sides and footslopes. Windsor and Denchworth soils occur on moderate slopes. The association occurs in Hertfordshire in small areas between Bishops Stortford and Ware on Reading Beds and London Clay, and also near Rickmansworth. Wickham and Windsor series are the main soils.

In Wiltshire, the association occurs in south-east of Salisbury. Here, the main soils are Wickham and Denchworth series. There are few Windsor soils, but patches of Bursledon soils are developed in impersistent loamy seams in the Tertiary deposits.

In the Thames valley, on Reading Beds and London Clay, the relative frequency of the associate Denchworth and Windsor soils changes from west to east: there are more Denchworth soils in west Berkshire, the two series are equally extensive in east Berkshire, and Windsor soils more frequent in Surrey and Greater London. Lawford series, similar to Denchworth series but in stony clayey Head, is also found on footslopes in Surrey and Greater London. There are small areas in Kent on London Clay. Here the Wickham soils are mostly fine silty in their upper layers. In south Hampshire, Denchworth is the most common associate soil. Kings Newton series, a coarse loamy over clayey seasonally waterlogged soil, is common north-east of Southampton on the loamy Bracklesham Beds and in the northern New Forest, on Barton Clays. It is locally more widespread than Denchworth series.

As well as the principal soils described above, soils affected by groundwater are occasionally found on low ground. They include fine loamy Shabbington series, in drift, and coarse loamy Curdridge soils, developed in Tertiary sediments. Cuckney soils, well drained brown sands, occur in west Berkshire between Newbury and Reading on sandy Reading Beds where they were formerly mapped as Shedfield series.

In the northern part of the Isle of Wight on the Bembridge Marls and Hamstead Beds, and on parts of the Osborne and Headon Beds, Wickham soils are dominant, with Denchworth series the main associate soil. Windsor soils are absent, but calcareous clayey Evesham soils occur locally on the Bembridge Marls. Loamy seams in the Hamstead Beds form higher land which has seasonally waterlogged Curdridge soils, as around Havenstreet.

Soil Water Regime

Most component soils are waterlogged for long periods (Wetness Class IV) where undrained. The slowly permeable clayey subsoils and moisture retentive surface horizons lead to poor water infiltration and rapid run-off. Underdrainage in these soils improves the rate of removal of excess water in winter (Trafford and Walpole 1975) and reduces waterlogging (Wetness Class III). Comparison of profile available water and crop-adjusted mean potential soil moisture deficits indicates that Wickham, Denchworth and Windsor soils in south Hampshire are slightly droughty for cereals and moderately droughty for grass. Soils in west Berkshire are slightly less droughty for most crops but the drought risk is greater in the drier climate of north Kent.

Cropping and Land Use

The soils remain difficult to cultivate however, and there is little opportunity for work on the land in spring, so autumn cultivations are essential and winter cereals are the main arable crops. Wickham and Windsor soils are naturally acid, but the acidity of arable soils depends on past liming history. Nevertheless base saturation is generally moderate or high, and there are no systematic nutrient or trace element deficiences.

In the South East with well planned management, winter cereals can be grown successfully on sloping land and where drainage has been installed, but poaching in winter and poor growth in summer because of droughtiness reduces grassland production and stocking densities are low. Grass yields are enhanced in south Hampshire, however, by a flush of growth in autumn.

Because the land is wet and heavy, woods are common, particularly in west Berkshire, Surrey, the Isle of Wight and Hampshire. Some are very old, dating back to prehistoric times. Sites of Special Scientific Interest valued for their flora and fauna, include Windsor Forest, and Blean Woods in Kent. Most is mixed deciduous woodland, but woods dominated by oak, beech, hornbeam and chestnut also occur. There is some coniferous woodland in Berkshire and Hampshire.

0711h WICKHAM 4

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

South Eastern Region

Typical Landscapes

South Eastern Region

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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: www.landis.org.uk. Cranfield University, UK. Last accessed 19/04/2024