Geodenna68(1995)67-78 Spatial variation and temporal persistence of grapevine response to a soil texture gradient Thierry Winkel lva, Serge Rambal aT*, Thierry Bariac b zyxwvutsrqponmlk a Centre d’Ecologie Fonctionnelle et Evolutive, Centre National de la Recherche Scientifque, BP 5051, F-34033 Montpellier, France b Laboratoire de Biochimie Isotopique, Universite' Pierre et Marie Curie, 4 place Jussieu, F- 75252 Paris, France Received 3 June 1994; accepted 9 March 1995 zyxwvutsrqponmlkjihgfedcbaZYXW Abstract Studying the water transport in the soil-plant system requires information on the spatio-temporal variability of both subsystems and the ability to assess the impact of the soil heterogeneity and of the biological responses on the coupling between vegetation and its substrate. This study was conducted for 2 years in a vineyard in the Aude Valley, France, by measuring the particle size distribution of the topsoil, the instantaneous isotopic ratios ( ‘sO/‘6O, ‘H/‘H) of leaf water, annual shoot biomass production, and interannual persistence of this biomass along a 360 m transect. The resultant spatial series were analysed for their correlations and converted to spectra. Changes in the isotopic ratios along the transect reflect the soil texture gradient, suggesting that the vines root deeper on the gravel layers than elsewhere. This could provide a mechanism for the partial decoupling between soil and vegetation, and thus explain ( 1) the strong temporal persistence of the vegetation pattern, (2) the low overall correlation between biomass production and soil texture. The spectra show that this correlation concentrates at specific scales which correspond to a minimum variability in the shoot biomass. In this case, therefore, soil texture plays only a minor role in determining the spatial heterogeneity of shoot biomass in grapevine. 1. Introduction Soil physicists and hydrologists have striven for several decades to apply the theoretical laws of soil water flow developed in the nineteenth century to natural watersheds and agricultural lands (see the review by Sposito, 1986). This has proved difficult because of extensive spatial variation in soil properties. Several authors have described such variation * Corresponding author. ’ Present address: O.R.S.T.O.M., BP 11416, Niamey, Niger. 0016-7061/95/$0.95 8 1995 Elsevier Science B.V. All rights reserved SX’IOO16-7061(95)00026-7