A Further Case for the Preservation of Earthwork Ridge-and-Furrow
Palmer, Rog, Antiquity
Medieval ridge-and-furrow cultivation, once widespread in many parts of England, is probably near the bottom of the many archaeologist's 'top 100' lists. The purpose of this note is not to press for a raising of its status in its own right - there are others better qualified to do that - but to indicate its value to the prehistorian and students of Romano-British archaeology.
'How come?', you may ask. 'All it does is cover those earlier features.' That is precisely the point. By its very nature this blanket of later cultivation served, and in cases probably still serves, as a protective cover. The accumulated soil covering arising from the medieval cultivation has effectively capped and sealed earlier deposits. Plough action, turning the soil into the middle of each strip, plus manuring, was responsible for the creation of each ridge. Between each ridge are the furrows. These cut into the subsoil and caused damage to layers below, although it has been shown that some 50% of the old land surface survives under the ridges (Hall 1972: [ILLUSTRATION FOR FIGURE 2 OMITTED]: reproduced here as [ILLUSTRATION FOR FIGURE 1 OMITTED]). On the heavier clay soils, some areas of ridge-and-furrow remain as earthworks with ridges up to 1 metre high. On the easier gravel soils, any earthwork remains are much slighter; most medieval fields are completely levelled, although they may be seen as crop-or soil-marked lines from the air. Large extents of clay-land ridge-and-furrow have also been levelled - as a result of war-time ploughing, through the introduction of increasingly powerful farm machinery or, more recently, through the incentive of set-aside.
This range of remains provides us with three strands to the story: the levelled remains on clay, the lesson from the river gravels, and surviving earthwork ridge-and-furrow.
Most aerial photographers, enjoying the sense of discovery inherent in their pastime, have flown more frequently in summer over ground known to produce crop marks. From the 1970s, some aerial photographers began to look at supposedly unproductive soils where they sometimes recorded the occasional feature. Flying over the Midlands, James Pickering identified crop-marked sites on the clay where previously only medieval fields had been known. In Northamptonshire, Glenn Foard patiently learned that reconnaissance over arable clay lands was best undertaken very late in the growing season when levelled ditched features may produce very slight crop marks. Over the last five years, similar examination of the clay in the Bourn area of west Cambridgeshire has been carried out by Air Photo Services (funded by an RCHME flying grant). The SMR maps for Cambridgeshire show much of the Bourn area to have been covered by ridge-and-furrow. One aspect of our Bourn area reconnaissance was to examine the clay lands in an attempt to discover whether plough-levelling of once-extensive medieval fields had created conditions suitable for observation of earlier features as results from adjacent counties suggested. The theory behind the proposition is relatively straightforward.
Medieval ridge-and-furrow provided a covering blanket for earlier features. Now we must imagine that blanket to be wearing thin; the medieval fields have been levelled and annual ploughing is gradually eroding the depth of the protective ground surface. This ploughing, the theory continues, has gradually lowered the topsoil cover until it is possible for sub-surface features from earlier settlement to affect the growth of responsive crops. These crop-marked features, which make less stunning pictures than some of their light-soil counterparts, are harder for the aerial photographer to see and record. It would seem likely that those recorded to date represent just the tip of the clay-land iceberg. As plough erosion continues we must expect, and be prepared to record, more crop-marked evidence of earlier use of the clay lands. …