The leaching of non-adsorbed tracer ions was studied at two field sites and in undisturbed columns. Results of field work are compared with leaching predicted using a simple chromatographic plate model. This comparison shows that in most cases less leaching than predicted occurs. This suggests that nitrate ions may be protected from leaching in field soils because of the presence of immobile water, and column experiments support this hypothesis. The extent of protection is larger than observed in other work for soils of similar texture.
