The determination of the soil water retention curve is a fundamental part of the characterization of soil hydraulic properties. Although soil water retention has been studied for a long time, many details on spatial variability of curves and experimental values are not well known. Knowing on this variability allows a better planning of experiments leading to simplification of sampling. The aim of the study was to explore the procedures for the analysis of the soil water retention curve in order to have a better description of their spatial variability. An experiment was conducted with undisturbed soil samples from a straight line transect using three replicates at every 2 m, from five depths. Each soil sample was submitted to 7 different tensions. The saturated soil water content was estimated based on bulk and particle density. Descriptive and exploratory analyses were carried out and it was found that the majority of data presented a normal distribution. The elimination of outliers improved normality without leading to a high data loss. Geostatistic analysis showed spatial dependency and at some tensions dependency structures occurred in two scales. An agreement analysis of curves as a function of distance showed significant differences among replicates at each location compared to their neighbors, though the decrease of agreement with distance was not significant.
soil-water relation; geostatistics; agreement analysis
