title: Practical improvements in soil redox potential (Eh) measurement for characterisation of soil properties. Application for comparison of conventional and conservation agriculture cropping systems.
abstract: The soil redox potential (Eh) can provide essential information to characterise soil conditions. In practice, however, numerous problems may arise regarding: (i) Eh determination in soils, especially aerobic soils, e.g. variations in the instrumentation and methodology for Eh measurement, high spatial and temporal Eh variability in soils, irreversibility of the redox reaction at the surface electrode, chemical disequilibrium; and (ii) measurement interpretation. This study aimed at developing a standardised method for redox potential measurement in soils, in order to use Eh as a soil quality indicator. This paper presents practical improvements in soil Eh measurement, especially regarding the control of electromagnetic perturbations, electrode choice and preparation, soil sample preparation (drying procedure) and soil:water extraction rate. The repeatability and reproducibility of the measurement method developed are highlighted. The use of Eh corrected at pH7, pe+pH or rH2, which are equivalent notions, is proposed to facilitate interpretation of the results. The application of this Eh measurement method allows characterisation of soil conditions with sufficient repeatability, reproducibility and accuracy to demonstrate that conservation agriculture systems positively alter the protonic and electronic balance of soil as compared to conventional systems.
authors.affiliation: CIRAD/PERSYST/UPR 115 AIDA and AfricaRice Centre, 01 BP 2031 Cotonou, Benin. Electronic address: Olivier.husson@cirad.fr.
authors.forename: Olivier
authors.initials: O
authors.lastname: Husson
authors.affiliation: IDEEAQUACULTURE, Parc Euromédecine 2, 39 Rue Jean Giroux, 34080 Montpellier, France. Electronic address: bhusson@ideeaquaculture.com.
authors.forename: Benoit
authors.initials: B
authors.lastname: Husson
authors.affiliation: CIRAD/US 49 Analyse, Avenue Agropolis, TA B-49/01, 34398 Montpellier Cedex, France. Electronic address: brunet.alexandre@outlook.com.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Brunet
authors.affiliation: CIRAD/US 49 Analyse, Avenue Agropolis, TA B-49/01, 34398 Montpellier Cedex, France. Electronic address: Daniel.babre@cirad.fr.
authors.forename: Daniel
authors.initials: D
authors.lastname: Babre
authors.affiliation: CIRAD/US 49 Analyse, Avenue Agropolis, TA B-49/01, 34398 Montpellier Cedex, France. Electronic address: Karine.alary@cirad.fr.
authors.forename: Karine
authors.initials: K
authors.lastname: Alary
authors.affiliation: ENSAT/INRA/INP UMR AGIR. BP 52627, Chemin de Borde Rouge, 31326 Castanet-Tolosan Cedex, France. Electronic address: sarthou@ensat.fr.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Sarthou
authors.affiliation: La Boisfarderie, Brives 36100, France. Electronic address: Charpentier.hub@wanadoo.fr.
authors.forename: Hubert
authors.initials: H
authors.lastname: Charpentier
authors.affiliation: Le Cazals, Castanet 81 150, France. Electronic address: earldeslacs@orange.fr.
authors.forename: Michel
authors.initials: M
authors.lastname: Durand
authors.affiliation: Agrotest fyto, Kromeriz Institute, Havlíckova 2787, 76701 Kromeriz, Czech Republic. Electronic address: benada@vukrom.cz.
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Benada
authors.affiliation: UMR CNRS/UdS 7140, Université de Strasbourg, Institut Le Bel, 4, rue Blaise Pascal, CS 90032, Strasbourg 67081, France. Electronic address: henry@unistra.fr.
authors.forename: Marc
authors.initials: M
authors.lastname: Henry
mesh_terms: D018556:Crops, Agricultural; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D012987:Soil / Q000737:chemistry*
chemical_list: D012987:Soil
keywords: Accuracy; Indicator; Method; Redox potential; Repeatability; Reproducibility