Relationship between Aggregate Stability and Selected Soil Properties in Taleghan Watershed

Aggregate stability is a fundamental property influencing upon soil erosibility and main hydraulic and physical characteristics. Knowledge of soil components controlling aggregate stability is very important for soil structure conservation. Also, identification of the critical soil properties affecting aggregate stability is central to understanding where erosion might be located within a catchment as a result of natural patterns in aggregate stability. The objective of this study, carried out in surface soils of Taleghan, was to investigate the relationship between aggregate stability and some selected soil properties. In this study, based on homogeneity in slope, aspect, and lithology work units were prepared, and then by relying on results of geostatistical studies in homogeneous work units in soils of Taleghan watershed, with an area of 3260 hectares, 84 points were selected as the soil sampling points. The applied indices of stability were the mean weight diameter (MWD) and wet aggregate stability (WAS). Correlation between mean weight diameter and measured properties were extracted using Pearson correlation coefficient and evaluated in terms of their statistical significance. Then, based on the results of correlation and using stepwise regression, models of aggregate stability prediction were developed. The unexpected results have been obtained from correlation between soil properties and aggregate stability so that the correlation between aggregate stability and the percentage of Caco3, clay and saturation were negative while that of fine sand and very fine sand were positive. Thus, the improvement of aggregate stability and soil erosion control in Taleghan watershed depends on management of these soil properties and soil conservation projects in order to adjust and optimize them.