COMPARISON OF INTERPOLATION METHODS FOR EDAPHIC WATER VARIABLES

Abstract

In this paper a comparison of three interpolation methods: Kriging, Thin Plaque, and Square Inverse Distance, is presented. Water variables of the soil, saturated hydraulic conductivity (SHC), field capacity (FC), and permanent wilting point (PWP) were utilized in order to determine which method is more accurate in terms of their estimated variance. In addition, two alternative forms to the method of classical statistics were proposed to define the minimum amount of SHC determinations to be carried out in order to obtain its average value with a certain accuracy. The field work was carried out at the Campus Tabasco located in Cárdenas, Tabasco; on the C-7 plot a grid with equal distant points was drawn every 25 m, having 204 points. SHC determinations were carried out by the hole method; samples for the determination of FC and PWP were collected. Results indicated that the best method was Kriging followed by the Square Inverse Distance. The most unaccurate was the Thin Plaque. The two forms proposed for the determination of the average value of SHC were more efficient than the method based on classical statistics.