Bioavailability and extractability of copper and zinc in a soil amended with pig slurry: Effect of iron deficiency in the rhizosphere of two grasses
| Autor: | P. Hinsinger, S. Thomas, Marc F. Benedetti, P. Peu, F. Persin, D. Mahammedi, M. Clairotte, José Mario Martínez, M. Castrec-Rouelle |
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| Přispěvatelé: | Biogéochimie et écologie des milieux continentaux (Bioemco), Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA)-École normale supérieure - Paris (ENS Paris), P.M. Huang & G.R. Gobran Eds., Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2004 |
| Předmět: |
2. Zero hunger
0106 biological sciences chemistry.chemical_classification Rhizosphere Topsoil Materials science food and beverages 04 agricultural and veterinary sciences 15. Life on land 01 natural sciences Bioavailability chemistry Agronomy [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry Environmental chemistry Soil water 040103 agronomy & agriculture Slurry 0401 agriculture forestry and fisheries Organic matter Phytotoxicity Iron deficiency (plant disorder) 010606 plant biology & botany |
| Zdroj: | Biogeochemistry of Trace Elements in the Rhizosphere P.M. Huang & G.R. Gobran Eds. Biogeochemistry of Trace Elements in the Rhizosphere, elsevier, pp.337-363, 2004 |
| Popis: | 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 consecutive years. A first objective was to evaluate the effect of pig slurry application on the bioavailability 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. It was found that amounts of extractable Cu and Zn significantly increased as a consequence of heavy applications of pig slurry in the topsoil of the field site, regardless of the chemical extractant. However, the bioavailability of soil Cu and Zn, as assessed by plant analysis, was not always affected by pig slurry application. When assessed in situ, Cu and Zn concentrations in ryegrass shoots did not consistently increase with increasing applications of pig slurry. For Cu, however, the concentrations were occasionally far above the threshold concentration in forage for sensitive animals such as sheep, suggesting that the direct contamination of plant shoots by particles of pig slurry renders such an agricultural practice questionable for grazing or forage production. Plant biotests that accounted for both shoot and root metal contents showed a significant increase in the bioavailability of Cu in the soil treated with pig slurry. In contrast, no significant increase in Zn bioavailability was found. No evidence of phytotoxicity was recorded over the short term of the biotest. In the two grasses being studied, we found, as expected, that Fe deficiency increased the exudation of phytosiderophores from roots. Such root exudates dramatically affected Cu and Zn speciation and complexation in aqueous solution, as evidenced by differential pulse anodic stripping voltametry. This may explain the enhanced Cu and Zn acquisition that occurred under Fe deficiency in both ryegrass and wheat. Root-induced changes in Cu and Zn extractability in the rhizosphere revealed a depletion of two major fractions of soil Cu and Zn, i.e. metals bound either to metal oxides or to organic matter, as determined by a sodium dithionite– acetate–citrate extraction or by a sodium pyrophosphate extraction, respectively. The amount of bioavailable Cu as deduced from plant uptake was in good agreement with the amount of Cu depleted from the metal oxide-bound fraction of soil Cu (determined by a sodium dithionite–acetate–citrate extraction) in the rhizosphere of ryegrass and wheat. Additional research is, however, needed to ascertain the precise mechanisms responsible for Cu and Zn acquisition by these two grasses, and the involvement of root exudates such as phytosiderophores. |
| Databáze: | OpenAIRE |
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