Ploughing is probably the greatest agent of attrition to archaeological sites world-wide. In every country, every year, a bit more is shaved off buried strata and a bit more of the past becomes unreadable. On the other hand, people must eat and crops must be planted. How can the fields be best managed to get the best of both worlds? Perhaps the most pressing need for resource managers is to know how quickly a particular field is eroding: negotiation and protection is then possible. Up to now that has been difficult to measure.
The new procedure presented here, which draws on the unexpected benefits of nuclear weapons testing, shows how variation in the concentration of the radioisotope 137Cs can be used to monitor soil movements over the last 40 years. The measurements allow a site's ‘life expectancy’ to be calculated, and there are some promising dividends for tracking site formation processes.