Micromorphologic Study of Pores and Porosity of Some Saline-Sodic Soils in theWest of Urmia Lake using Image Analysis

Document Type : Research Paper

Authors

Abstract

Soil micromorphology is a branch of soil science which studies undisturbed soil samples using
microscopic methods and the image analysis technique can promote speed, accuracy and ability of
micromorphic studies. Soil pores due to their effect on the most of processes and properties of soils
and also on interaction between soil, water and plant, have spacial importance. In this study, soil
pores type and total porosity of saline-sodic soils were studied using micromorphic and Image
Analysis techniques in a transect composed of eight soil profiles in the west of Urmia Lake.
According to microscopic observations, pore types in these soils were vughs, channels and planar
voids but Voids size and frequency in different horizons of each profile and all eight profiles were
different. Average values of vughs, channels and planar voids in each thin section were about 45-
50%, 35-45% and 5-25%, respectively. Comparison between thin section description and Image
Analysis showed that frequency and the range of size of pores in Image Analysis technique was
greater than that of thin section description. The differences of measured total porosity between
Image Analysis and thin section description in profiles 1 to 4 were 10.7, 7.83, 6.7 and 9 percent
respectively. The reason of this difference is that, in thin section description technique, some of
voids are too small, so they cannot be seen and are not measurable, whereas, in Image Analysis
technique the measurement of size and frequency of voids were based on the number of pixels and
this leads to greater values in Image analysis technique.

Keywords

Main Subjects