Ploughzone Archaeology NHPP Activity 4G2
Research carried out 2011-2015 into improving our understanding of the significance and management issues of archaeology within and immediately beneath the ploughzone. This formed part of the National Heritage Protection programme.
Scope of the activity
The ploughzone is the upper layer of soil that has been disturbed by agricultural activity. Typically this is about 30cm in depth and is commonly referred to as topsoil or in geomorphological terms as the ‘A-horizon’.
The NHPP consultation process found that ploughzone archaeology is ‘insufficiently understood, significantly threatened by change, and of potentially high significance’. The scope of this activity is therefore to increase our understanding of this resource and the threats to it, in order to judge its significance better and to provide appropriate management advice.
Any archaeological remains from the ploughzone have been disturbed rather than found within features such as pits or ditches. Despite this, evidence from within and immediately beneath the ploughzone can still be highly significant. Many prehistoric sites, especially of the Mesolithic and Neolithic, now survive largely or wholly as ploughzone assemblages, as do some site types from later periods.
Archaeological evidence within the ploughzone might be:
- From features surviving below the ploughzone, in which case the material in the ploughzone is indicative of the presence of a site that is being damaged by agricultural activity and might be all that is left of the later phases. In extreme cases it may be all that is left of features that have been completely ploughed away.
- Originally deposited as surface scatters, for example material from lithic scatters (of stone tools or waste from making them), early medieval ‘productive sites’ (scatters of artefacts thought to have been lost during periodic gatherings such as fairs) or battlefields.
- From single events such as hoard deposition, usually discovered as chance finds such as the Staffordshire Hoard.
- Evidence for ‘off-site’ activity such as re-depositing of settlement middens through manuring.
The greater the accuracy with which evidence from the ploughzone can be located, the better the understanding of the material that can be developed from its analysis. Therefore, ploughzone evidence is usually collected within a structured framework, such as a grid, or accurately located by some other means, such as a Global Positioning System (GPS). The evidence can include a wide range of artefacts and other information such as the soil’s chemical composition.
Evidence from the ploughzone is typically recovered in the following ways:
- Surface collections or fieldwalking
- Metal detecting
- Test pitting
- Chemical analysis of the topsoil
- Sieving or monitoring of topsoil removed during other investigations
Designation (scheduling) is not at present a viable means of protecting most ploughzone sites. Instead, action will focus on developing a detailed understanding of site characteristics and distributions, measures for assigning significance (i.e. equivalent to principles of selection for assets that can be designated) and guidance to ensure their significance is recognised and assessed, and that they are managed appropriately.
Projects in Activity 4G2
Update 'Our Portable Past' Guidance
This revision of our previous guidance document is now complete. It has required research and assessment of recent literature and projects to develop the revised text. The new version includes more information on developing projects, combining techniques and on post fieldwork processes such as archiving. See the revised document.
Use of Ploughzone Data in Historic Environment Records
This project was undertaken by Oxford Archaeology on our behalf. It looked at how ploughzone archaeology is recorded in local Historic Environment Records (HERs), examining information from seven HERs, and identified strengths, weakness and recommended possible improvements. You can find out more from the summary report.
Supporting the Damerham Archaeology Project
The Damerham Archaeology Project is investigating a complex of Neolithic and Bronze Age features and their environs at Damerham, Hampshire. It is a voluntary project carried out by archaeology professionals and local people. The methods used include a programme of fieldwalking: the Ploughzone Activity supports the project to assess the distribution of artefacts and model a range of collection strategies used in this technique. You can read the interim report comparing different surface collection methods used at Damerham. You can also find out more about the wider archaeology of Damerham from the project website.
Links to Other Activities
Work in this area has links to other NHPP Activities including:
- 2B2 Heritage crime (‘nighthawking’)
- 2D1 Agricultural and forestry impacts (ploughing).
- 3A4 Identification of terrestrial assets through non-intrusive survey (testing methodology, for example the NAIS project in West Wiltshire)
- 4E1 Battlefields (methodology)
- 4G1 Pleistocene and Early Holocene Archaeology (ploughzone finds are key evidence for this period)
- 5B1 Management frameworks (management of ploughzone archaeology)
- 8A1 Reducing risk to heritage assets through expert advice (guidance)
- 8A5 Offsetting loss through knowledge dividend (last resort, chance discoveries)