Geochemical Resilience of a Ferralsol Subjected to Anoxia and Organic Matter Amendment
- Jasmina Lahlaha,
- Pierre Renault *a,
- Patrick Cazevieilleb,
- Aurélie Buzeta,
- Jean-Louis Hazemannc,
- Manfred Womesd and
- Philippe Cambiere
- a INRA-UAPV, UMR 1114 Environ. Méditerranéen et, Modélisation des Agro-Hydrosystèmes, Domaine Saint-Paul, Site Agroparc, 84914 Avignon, Cedex 9, France
b UR CIRAD Risque environ. lié au recyclage, TA B78/01 Avenue Agropolis, 34398 Montpellier, Cedex 5, France
c Institut Néel, UPR CNRS 2940, MCMF, 25 Avenue des Martyrs, 38042 Grenoble, Cedex 9, France
d Institut Charles Gerhardt, Equipe Agrégats, Interfaces, Matériaux pour, l'Energie (UMR CNRS 5253), Place Eugène Bataillon, 34095 Montpellier, Cedex 5, France
e UMR INRA-AgroParisTech, Environnement et Grandes Cultures, 78850 Thiverval-Grignon, France
The spreading of vinasse on soils may favor not only anoxia but also mineral alterations and metal mobilization. Our aims were to record the geochemical changes occurring in a ferralsol subjected to vinasse input and anaerobiosis, and to check for soil resilience after a return to aerobic conditions. Soil slurries were therefore incubated under successive 7 d of aerobic, 0 to 28 d of anaerobic, and 28 d of aerobic conditions, vinasse being supplied at one of three levels when anaerobiosis began. At several dates, the slurry solution was characterized (pH and organic and mineral compounds) and Mn and Fe oxidation states in solids were assessed. Before incubations, about 20% of the Fe in solids was already reduced, whereas almost all Mn was found as Mn(IV). During the first aerobic period, mobilized metals included Pb, Zn, Ni, Cu, and Cr. After vinasse input during the first 14 d of anaerobiosis, the principal biotransformations were fermentation and true acetogenesis; Fe and Mn were mobilized during this period (up to 4.05 and 6.2 mmol L−1, respectively), and most Mn and an unknown but small fraction of Fe in solids were reduced. During the subsequent 14 d of anaerobiosis, only acetoclastic methanogenesis was observed. The return to aerobic conditions led to rapid oxidative immobilization of Fe, desorption of exchangeable Fe(II), and the partial immobilization of other metals (Ca, Mg, K, Na, Mn, Pb, and Ni). Manganese was not oxidized, and there was no return to the initial conditions for Fe and Mn in solids.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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