Determining the Effect of Soil Properties on Runoff and Sediment at Suborder Level Using Principal Components Analysis (Case Study: Ardabil Plain)

Understanding the factors and processes affecting soil erosion and sedimentation in an area is an essential for providing a suitable strategy for soil conservation. In this research, the effect of soil characteristics on runoff and sediment yield was reviewed using a rain simulator in Ardabil plain. Principle component analysis (PCA) was used to show the effect of soil properties. Surface soil sampling was carried out at 77 points in the form of 3500 × 3500 m regular grids and runoff and sediment sampling using 40-point rain simulator. Some physical and chemical properties of soils (texture, saturation moisture, organic carbon, electrical conductivity, acidity, total nitrogen and potassium) were measured in the laboratory. In addition, the vegetation cover percentage was measured by plot at sampling points. Simulation of rain (intensity of 23.9 mm h-1 in 10 minutes) was carried out at 40 sampling points and runoff and sediment samples were taken and transferred to the laboratory. The representative soil profiles descriped to suborder level using Soil Taxonomy. The principal component analysis (PCA) results showed that nine factors of 13 investigated factors were located in first three principle component that contribute of 57.1% of total variation in erosion changes. According to the results, the highest amount of runoff (4.8 l m-2) and sediment (58 g m-2) was measured in Psamments because of low organic carbon content (0.78%) in this suborder which reduced soil permeability and amount of generated runoff increases. The lowest amount of runoff (2.4 l m-2) and sediment (21.84 g m-2) were observed at Xeralfs, where the amount of organic carbon (3.21%) and aggregate stability (6.59%) are high that increases permeability and reduces soil losses.