Analysis of the matrix potential - water-content curves obtained in situ during an irrigation experiment

The follow-up of an irrigation experiment may afford an opportunity to learn more about the water behaviour of a soil and its characteristics when neutron and tensiometric measurements are performed simultaneously. Thus, on the basis of measurements of water diffusion in the soil during localized irrigation in an orchard using water from the Bas-Rhone-Languedoc system, the primary objective of which was to analyse the variation in time of the soil moisture content and water potential as a function of different treatments, it was possible, by relating these two types of data, to correlate the curves for the matrix potential versus soil humidity in situ. In spite of certain approximations stemming from the practical measurement conditions, analysis of the curves obtained shows a variability associated with the heterogeneity of the various soil layers and the intensity of the drying and rewetting phenomena. The possible practical consequences (monitoring of irrigation) of these observations are considered. (author)