Bioavailability and extractability of copper and zinc in a soil amended with pig slurry : effect of iron deficiency in the rhizosphere of two grasses
Biodisponibilité et extractabilité du cuivre et du zinc dans un sol amendé avec du lisier de porc : effet d'un manque de fer dans la rhizosphère de deux graminées
Résumé
The application of pig slurry in agricultural land is a potential source of Cu and Zn contamination of soils. This study was conducted at the Solepur experimental site in Brittany, northwestern France, which received massive, controlled applications of pig slurry over 5 consecutives years. A first objective was to evaluate the effect of pig slurry application on the biovailability and chemical extractability of soil Cu and Zn. The bioavailability was assessed (i) either in situ via the analysis of ryegrass shoots (ii) or ex situ via a biotest with two grasses, ryegrass and wheat, which enabled easy access to plant roots and to the rhizosphere. A second objective was to examine precisely how rhizosphere processes could affect the bioavailability and chemical extractability of soil Cu and Zn, with a particular emphasis on the exudation of phytosiderophores as related to Fe deficiency.