IDW Interpolation of Soil Moisture Retention Curve Utilizing GIS

Abstract

This search aim to analyse the Soil Moisture Retention Curve (SMRC) by spatial interpolation mapping using Inverse Distance Weighted scheme (IDW). The SMRC is a Graphical Representation the mathematical relationship between the metric suction of soil (it represents the difference between the pore of air pressure (ua), and the pore of water pressure (uw) and either soil water contents (volumetric and gravimetric) or S (degree of saturation). The soil samples were obtained from three locations of Baghdad University by drilling pits of depth 0.5 to 1 m under the ground level. An extensive Laboratory Testing Program was performed on the studied samples. Rosetta program was utilized to estimate Unsaturated Hydraulic properties from the data of surrogate soil such as the data of soil texture and bulk density. After obtaining the properties for the three soil samples applying IDW spatial interpolation techniques by utilizing the Arc Map-GIS program on a satellite image of the Landsat-8 satellite with a high recognition accuracy for studding properties for the areas surrounding calculated points.