The study presents nitrogen isotope data from prehistoric and Medieval charred cereal grains and grains from modern experiments in the Czech Republic and Slovakia. The results are consistent with δ¹⁵N values of cereals from other European countries. Various crops were manured differently, perhaps according to specific societal needs. Surprisingly, the highest (but also the lowest) δ¹⁵N value is found in barley. In modern experiments, means of fertilisation other than farmyard manure were tested. Based on these findings, and on soil analysis and prehistoric settlement activity observed within an agricultural landscape, we propose an alternative method for maintaining soil productivity by the periodic movement of fields within the settlement areas into places intensively fertilised by abandoned habitation areas, and vice versa.

The results of the isotopic analysis of more than 700 archaeobotanical samples of cereal grains from Europe show that the improvement and maintenance of good soil productivity by adding organic material has been practised everywhere, to a greater or lesser extent, since the very beginnings of agricultural history, and confirm the high level of skill in prehistoric and Early Medieval farming practices.