Soil Quality Analysis of the Shazand Watershed Ecosystem

Increasing knowledge and soil quality evaluation in different ecosystems is important to improve sustainable land use management and to decrease land degradation. Therefore, the present study was planned to analyse the effects of different land use (irrigated farms, rain fed farms, orchards and rangelands), texture and topography on soil quality of Shazand Watershed with an area of 1740 km2. For this purpose, 140 soil samples were taken from top layer of the soil (0 to 30 cm) from homogeneous units representing an area of more than one square kilometers. Hence, various soil properties such as electrical connectivity (EC), pH, bulk density (BD), gravel, sand, silt, clay, calcium carbonate (CaCO3), nitrogen (N), soil organic carbon (SOC) were analyzed. Consequently, the effect of land uses, textures, slopes, and elevation on the measured soil properties were examined using multivariate analysis of variance (MANOVA). The result of MANOVA indicated that the different land uses had no significant effect (P> 0.05) on different soil properties. Also, the minimum effective properties on soil quality were determined by the minimum data set (MDS) with the help of principal components analysis (PCA). Finally, soil quality index values were calculated using discriminant analysis (DA). The results of PCA and DS showed that the EC, OM, CaCO3 and pH were influenced by soil texture, slope and elevation, respectively. Then, the comparison of mean soil quality values using the least significant differences (LSD) indicated poor soil quality on slopes less than 15% and elevations above 2000 m. The results of this research could be used for choosing appropriate management practices to control land degradation and to achieve sustainable development goals in different ecosystems of Shazand Watershed.