Soil Associations

0851a DOWNHOLLAND 1

Soil and site characteristics

Deep stoneless humose clayey soils, calcareous in places. Some peat soils and deep humose calcareous silty soils. Flat land. Groundwater usually controlled by ditches and pumps. Risk of wind erosion.

Geology

Marine alluvium and fen peat

Cropping and Land Use

Cereals, sugar beet, potatoes and field vegetables in the Fens; dairying on permanent grassland in the South West.

Component soil series

Subgroup	Series name	Percentage	WRB 2006 link
8.51	DOWNHOLLAND	35%	Clayic Fluvic Mollic Gleysols
8.52	EASTVILLE	20%	Fluvic Calcaric Histic Gleysols
8.52	CHATTERIS	15%	Fluvic Calcaric Mollic Gleysols
10.24	ADVENTURERS'	15%	Drainic Rheic Sapric Histosols

Covers 723 km² in England and Wales

Soilscapes Classification

23	Loamy and sandy soils with naturally high groundwater and a peaty surface

0851a DOWNHOLLAND 1

Detailed Description

This association on marine alluvium consists of clayey humic alluvial gley soils, Downholland series, clayey and silty calcareous humic alluvial gley soils, Eastville and Chatteris series, and earthy eutro-amorphous peat soils, Adventurers' series. As the original peat cover in the Fens has wasted the association has become extensive in Cambridgeshire, Norfolk and Lincolnshire and occurs also on the Somerset Levels and Moors, notably in the Axe valley. The land is flat but there is often a marked microrelief of low ridges, called rodhams in the Fens, marking the positions of former creeks and giving a complex soil pattern with silty soils on ridges and clayey and peaty soils on intervening ground. The association also includes soil series such as Tanvats, Wisbech, Wallasea, Midelney, Compton, Newchurch, Altcar and Prickwillow, but never all together, there being local differences in the soil pattern.

The composition varies because the various alluvial deposits have different stratigraphical relationships. In Cambridgeshire and Norfolk, the lower Fen Clay occurs at or below sea level but in Lincolnshire it is generally higher, up to 3 m O.D.. Downholland series is generally the most extensive soil but in Norfolk and Cambridgeshire the Downholland and Eastville series are co-dominant. Extremely acid sulphuric humic alluvial gley soils and earthy sulphuric peat soils (Prickwillow series) are common around the margins of the Fen Clay in Cambridgeshire, often where the clay is thin, but are less common in Lincolnshire. Patches of Adventurers' series found in low places in Lincolnshire are less widespread than in Cambridgeshire where the original peat cover was generally thicker. In Lincolnshire the topsoils are often slightly humose because of intensive arable use. In places, especially where the peat fen and upper marsh adjoin, Wallasea soils have developed following further loss of organic matter. Near Lincoln there are some humose clayey over sandy soils fringing the Witham fens. The large creek ridges here carry Chatteris and Wisbech soils. In Cambridgeshire some of the component peat soils are semi-fibrous and belong to Altcar series.

There are about 60 km² of the association in the Somerset Levels and Moors, mainly in the Axe valley between the Mendips and the Isle of Wedmore, formerly mapped as Allerton series and shallow Godney series peats. Eastville soils are common in which calcareous carbonate concretions are present at shallower depth than in the Downholland soils. The small areas of associated peat are nowadays thinner as a result of recent drainage improvements and only local patches of shallow phase Altcar or Adventurers' soils remain. Clayey riverine alluvium gives Midelney, Wensum or Compton series around the lowland edges or along streams.

Soil Water Regime

Most of these soils are well drained or only occasionally waterlogged (Wetness Class I or II) where water levels are controlled by ditches and pumps. The subsoils are normally very porous as a result of vertical channels created by the former reed vegetation and so respond well to drainage treatments. Apart from potatoes, arable crops only suffer from drought in unusually dry summers. However, where subsoil acidity restricts root growth, crops regularly suffer from summer drought.

In the South West the soils are seasonally waterlogged (Wetness Class IV) and were flooded at times in winter, but pump systems are now used to control water levels and flooding is rare.

Cropping and Land Use

Where drained, these soils are easy to work but are easily compacted where they are no longer peaty because of long arable use. The soils are rarely wet provided subsoiling is used to maintain continuous permeability from the plough layer to the porous subsoil. The patchy distribution of peaty, clayey and calcareous silty soils causes difficulty in the timing of field operations and the correct use of fertilizers. Standard applications of nitrogen sometimes cause patchy lodging and differential ripening in cereals on contrasting soils. Specially designed implements or double diggers have been used locally in Cambridgeshire to mix subsoil and topsoil to limit the loss of organic matter and break up acid layers that form barriers to rooting. Wind erosion of the peat soils is a problem in Cambridgeshire and Norfolk. The main crops are cereals, potatoes, sugar beet, peas and field vegetables but poor cereal finishing and weedy crops are common on the component peat soils. With direct drilling, yields of autumn-sown crops are likely to be similar to those from conventional cultivations, but the soils are less suited to those techniques for most spring-sown crops. Manganese deficiency occurs on the peat soils through overliming. In Somerset the land is in permanent grass capable of producing high yields but used mainly as summer pasture because the soils poach easily and are not trafficable when wet.

0851a DOWNHOLLAND 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

South Western Region

Eastern Region

Typical Landscapes

South Western Region

Eastern Region

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