HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Naasz, R. Articles by Charpentier, S. Search for Related Content PubMed Articles by Naasz, R. Articles by Charpentier, S. Agricola Articles by Naasz, R. Articles by Charpentier, S. Related Collections Soil Physics Hysteresis Laboratory Column Studies

Division S-1—Soil Physics

Measuring Hysteretic Hydraulic Properties of Peat and Pine Bark using a Transient Method

Unité Mixte de Recherche A_462 ‘SAGAH’ INRA/INH/Université d‘Angers, Sciences Agronomiques Appliquées à l‘Horticulture, 2 rue Le Nôtre, 49045 Angers Cedex, France

^* Corresponding author (remi.naasz{at}inh.fr).

The precise and continuous measurement of the hydraulic properties of growing media is of vital importance for the effective management of irrigation and fertilization. The main purpose of this study was to use a transient method to characterize the hydraulic properties of two horticultural substrates (peat and composted pine bark) and, second, to test the applicability of well-known hydraulic models commonly used on mineral soils. Substrate water retention and hydraulic conductivity curves were determined in the laboratory by the Instantaneous Profile Method (IPM), during a drying–wetting cycle. The results showed hysteresis for peat in the () curves (30% vol.) and in the K() curves [one order of magnitude in K()], whereas this phenomenon was very limited for pine bark [approximately 10% vol. in () and approximately a half-order of magnitude in K()]. The K() curves for both substrates considerably decreased after the considerable variation in water content observed in (), that is to say, after –5 and –3 kPa for peat and pine bark, respectively. Fitting the van Genuchten retention model to observed data resulted in a high correlation (0.96 R² 0.99) and fitting unsaturated hydraulic conductivity models (VGM and BC) resulted in a lower correlation (0.43 R² 0.64). Our results seemed to be in agreement with other hydraulic studies of substrates. These overall results implied that hydraulic properties of tested substrates widely fluctuate in a narrow range of water potentials that could therefore rapidly affect water and air availability to the roots. Knowledge of K() and K() curves, in addition to the () curve, could contribute to alleviating stress conditions.

Abbreviations: AC, air capacity • BC, Brooks and Corey • IPM, instantaneous profile method • PVDF, polyvinylidenfluoride • TDR, time domain reflectometry • VG, van Genuchten • VGM, van Genuchten-Mualem • WHC, water holding capacity

This article has been cited by other articles:

				K. Schwarzel, J. Simunek, H. Stoffregen, G. Wessolek, and M. Th. van Genuchten Estimation of the Unsaturated Hydraulic Conductivity of Peat Soils: Laboratory versus Field Data Vadose Zone J., May 26, 2006; 5(2): 628 - 640. [Abstract] [Full Text] [PDF]