Water repellency of organic growing media related to hysteretic water retention properties

Autor: Sylvain Charpentier, R. Naasz, Jean Charles Michel
Přispěvatelé: Unité de Recherche Environnement Physique de la plante Horticole (EPHOR), AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Université d'Angers (UA), Université d'Angers (UA)-AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)
Jazyk: angličtina
Rok vydání: 2008
Předmět:
Zdroj: European Journal of Soil Science
European Journal of Soil Science, Wiley, 2008, 59 (2), pp.156-159. ⟨10.1111/j.1365-2389.2007.00966.x⟩
ISSN: 1351-0754
1365-2389
DOI: 10.1111/j.1365-2389.2007.00966.x⟩
Popis: Summary With respect to soils, most growing media can exhibit hysteresis during drying/wetting cycles, which greatly affects their hydraulic properties. In the case of organic substrates, hydrophobicity during desiccation could be considered as one of the main factors leading to hysteretic behaviour. The purpose of this study was to estimate the influence of changes in wettability on the water retention properties, θ(ψ), of peat and pine bark during a drying/wetting cycle. Major differences in the hydraulic behaviour of the two organic materials studied were observed. For peat, hysteresis was found in the water retention curve (21%) and also in the contact angle/water potential relationship, (α(ψ), 20%), whereas in pine bark, this phenomenon was less pronounced in the water retention curve (10%) and even more limited in the α(ψ) curve (> 5%). Water retention hysteresis was successfully modelled using a modified van Genuchten-Durner approach (VGα model), which took into account the local hydrophobicity of each poral domain of the porous media, regardless of the extent of hysteresis. Incorporating the parameters of the VGα water retention model into a α(ψ) equation to characterize overall or average changes in the hydrophobicity of the material during desiccation resulted in values very similar to those of the contact angles calculated with the capillary rise method. These results indicate that water retention properties of these organic substrates are strongly influenced by hydrophobicity.
Databáze: OpenAIRE
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