Devon field boundaries: restoration standards for agri-environment schemes (TIN039)

Corn Ditches

This type of boundary has a ditch and a vertical stone face against the moor, and a sloping earth bank on the field side. The precise nature of the boundary can vary greatly in size and form.

Corn ditches are most likely to be found on the edge of open moorland and can date back to the medieval period. They were designed to deter animals from getting into the fields, and allow an easy exit to those who had managed to get in. Today they are found both on the outer edge of fields next to open moorland, and sometimes within enclosed farmland (indicating an earlier moorland boundary).

Please note:

Corn Ditches are important historic features. Restoration advice must be sought from your local adviser and from either an Historic Environment Adviser or your Local Authority Archaeologist before carrying out any work on a corn ditch.

The following are guidelines only:

  • The stone face on the moorland side should be repaired only as necessary to restore any collapsed sections. Care should be taken that these are built to match the existing stone work. Stone should be retrieved from the backfill of the ditch and subsequently reused. Any new stone imported must be sourced locally and must match the original stone.

Figure 13 Cross section of corn ditch showing position of fence
  • When a severely degraded stone face is stripped right back in preparation for restoration, ensure that the basal courses of stone are not disturbed as these are often of archaeological importance.
  • Do not disturb the earth slope on the field side or bank up the earth, as this will alter the original historic feature.
  • Old fencing (that may have originally been erected on top of the corn ditch) must be replaced with a fence at the base of the slope or bank (see figure 13).
  • On Common Land, if fencing is to be set at the base of the stone face you must obtain permission from the Secretary of State (contact Defra's Common Land Branch for more details).
  • Angled side wiring can be erected on the moorland side of a corn ditch to prevent livestock from jumping up the wall onto the bank. Either steel or wooden posts can be used set at an angle below the top of the wall, with three strands of wire set close together (figure 14).
  • If the ditch is to be cleared out this must done sympathetically using a small machine or by hand, to ensure that earlier surfaces underneath are not disturbed. The ditch should not be dug out any deeper than the original ditch profile. Material taken from the ditch can be cast up onto the crown of the bank.
  • Remove any large scrub or immature or deatrees from the top and sides of the wall to prevent the roots from damaging the stone work. Control any scrub on the bank.

Figure 14 Cross section of corn ditch showing position of top wiring
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