On heavy metals in soil; rationalization of extractions by dilute salt solutions, comparison of the extracted concentrations with uptake by ryegrass and lettuce, and the possible influence of pyrophosphate on plant uptake

absorption de substances nutritives cadmio cadmium cinc cobre copper cuivre heavy metals lactuca sativa lead lolium perenne metales pesados nutrient uptake pirofosfatos plomb plomo pollution du sol pyrophosphate pyrophosphates soil pollution zinc