Abstract
The effect of land use type on soil functioning within an ecosystem can be assessed and monitored using soil quality attributes. Such studies, which are carried out to create a balance between the biological production and the maintenance and improvement of land resource quality, provide a framework for land degradation control and also for identification of sustainable management. In this research investigated the effect of different land uses on soil physical quality indices. Three land uses including a natural pasture, dryland farming and irrigated farming were selected. From natural pasture 54 samples, dryland farming 40 samples and irrigated farming 17 samples were collected in the surface soil (0-15cm). Saturated hydraulic conductivity, infiltration rate, bulk density, soil distribution size, soil erodibility index, organic carbon and water aggregate stability (three classes) were determined for each land use. The results showed that mean, minimum and maximum of saturated hydraulic conductivity in irrigated farming land use is more than others land uses. Water aggregate stability index the macroaggregates (>2 mm) in irrigated farming land use is lower than others land uses. In the among studies variables, saturated hydraulic conductivity, clay percentage, soil erodibility index and water aggregate stability in macroaggregates in different land uses are significant differences in 5% level. Soil erodibility index and water aggregate stability for macroaggregates seems to be the most reliable soil quality indices for the area.

Keywords: Water aggregate stability, Soil quality index, Soil erodibility index