The dynamics of protons, aluminium, and calcium in the rhizosphere of maize cultivated in tropical acid soils : experimental study and modelling

Calba Henri, Firdaus, Cazevieille Patrick, Thée Charles, Poss Roland, Jaillard Benoît. 2004. The dynamics of protons, aluminium, and calcium in the rhizosphere of maize cultivated in tropical acid soils : experimental study and modelling. Plant and Soil, 260 : 33-46.

Résumé : The goals of this work were to understand the dynamics of H+, Al and Ca in the rhizosphere of maize cultivated in tropical acid soils, and to evaluate the contribution of the dissolution kinetics of the Al-hydroxides to AI dynamics. The study of the dissolution kinetics was based on a comparison between experimental and simulated data, using a model of the chemical processes in the rhizosphere. Two Oxisols, pH 5.1 and 4.6, and one Ultisol, pH 5.2, were studied. An Al-tolerant maize variety (Zea mays L.) was grown for 14 days on a 3-mm thick soil layer. The composition of the soil and the soil solution, together with the concentration of Al in the roots, were determined throughout the experiment. The results showed that root growth (i) decreased the soil solution pH, up to one pH unit, (ii) increased Al concentration in the soil solution, (iii) increased exchangeable Al, and (iv) decreased exchangeable Ca. Soil solution pH, exchangeable Al, and exchangeable Ca were closely linked. Exchangeable Al increasea 1.5 - 3.0 times, due to the dissolution of easily mobilised Al components. In addition, Al accumulation in roots depended mainly on Al in the soil solution. Modelling the interactions between H+, Al, and Ca proved that the main factor determining Al in the soil solution was the kinetic reactivity of the easily mobilised Al components. These components, probably poorly crystallised Al-hydroxides, are key players in the functioning of the rhizosphere in tropical acid soils.

Mots-clés Agrovoc : Zea mays, rhizosphère, sol acide, sol tropical, aluminium, calcium, hydroxyde, toxicité, modèle, expérimentation

Mots-clés complémentaires : Proton, Cinétique

Classification Agris : P33 - Chimie et physique du sol
P35 - Fertilité du sol
U10 - Informatique, mathématiques et statistiques

Auteurs et affiliations

• Calba Henri, CIRAD-AMIS-AGRONOMIE (FRA)
• Firdaus, INRA (FRA)
• Cazevieille Patrick, CIRAD-AMIS-AGRONOMIE (FRA)
• Thée Charles, IRAD (CMR)
• Poss Roland, IRD (FRA)
• Jaillard Benoît, INRA (FRA)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/528069/)

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