Catchment-scale spatial variability analysis of soil hydro-physical properties in a semi-arid region of Iran

Document Type: Research Paper

Authors

1 M.Sc. student, Shahrekord University, Shahrekord, Iran

2 Associate professor, Shahrekord University, Shahrekord, Iran

3 Assistant professor, Shahrekord University, Shahrekord, Iran

Abstract

Soil hydrau-physical data are important for many hydrological modelings. They are the main variables controlling
the key processes such as water and chemicals movement and transport in the soil profiles. This study was conducted
in order to analyze the spatial distribution of selected soil hydrau-physcial characteristics including infiltration rate
(IR), saturated hydraulic conductivity (Ks), bulk density (BD), clay, silt, and sand content. The study area was
sampled on a pseudo-regular sampling scheme with initial grid spacing of 1 km during June and July 2007.
Maximum coefficient of variation (CV) was found for IR (72%) and Ks (67%). While, BD showed a minimum CV of
9%. Statistical analyses illustrated that there is a significant difference (P<0.05) in the mean values of IR in two
different landforms, i.e., plateaus and alluvial plains. However, different land uses including rangelands and dry
farming revealed no significant differences in the mean values of measured IR. The contrasting results were obtained
for Ks. Geostatistical analyses revealed that the spatially dependent stochastic component (structure) was
predominant over the nugget variance (noise). The developed and modeled variograms of each variable were used in
generating kriged maps. As expected, these maps exploited spatial similarities among soil properties.

Keywords