Carpathian Journal of Earth and Environmental Sciences, May 2012, Vol. 7, No. 2, p. 93 - 100 SOIL EROSION MODELLING IN THE COMPLEX TERRAIN OF PIROT MUNICIPALITY Veljko PEROVIĆ 1 , Aleksandar ĐORĐEVIĆ 2 , Ljubomir ŽIVOTIĆ 2 , Nataša NIKOLIĆ 2 , Ratko KADOVIĆ 3 & Snežana BELANOVIĆ 3 1 Institute of Soil Science, Teodora Drajzera 7, 11000 Beograd veljko.s.perovic@gmail.com 2 University of Belgrade - Faculty of Agriculture, Nemanjina 6, 11080 Zemun, Serbia Corresponding author: ljubomirzivotic@yahoo.com 3 University of Belgrade - Faculty of Forestry, Kneza Višeslava 1, 11000 Belgrade, Serbia Abstract: This paper aims at assessment of soil erosion potential and its spatial distribution on the 1235 km 2 area of municipality Pirot located in south-eastern Serbia. The study was conducted by using well- known Universal Soil Loss Equation (USLE) model due to its modest data demand and transparent structure. The erosion factors of USLE were collected and processed through a GIS-based approach offering ease of elaboration and manipulation of erosive factors. All the erosive factors were determined on a 30 x 30 m cell basis and multiplied in order to obtain the map of potential average annual soil erosion. The average annual soil loss was estimated at 8.65 tha −1 yr −1 classifying the area of Pirot municipality under low erosion rate category. More than 80% of the municipality area was characterized by insignificant (< 3 tha −1 yr −1 ), and low erosion category (3-10 tha −1 yr −1 ). Around 7.8% of the area was found to be under moderate erosion category (10-20 tha −1 yr −1 ). High erosion category was found on 6.8% of the area (20-40 tha −1 yr −1 ), while there is around 5.2% of the area under very high erosion category (>40 tha −1 yr −1 ). It means that almost 15000 ha of the area of Pirot municipality are facing high and very high erosion. The analysis of vertical distribution of erosion processes pointed out that the zone between 500 and 800 m a.s.l suffers more from erosion than other elevation zones mainly due to land management. The results of this work are in agreement with the soil erosion map of Serbia, the sediment yield measurements in the basin and with other, more detailed, studies in the municipality. Therefore, the presented methodology could be applied as a framework for the evaluation of erosive factors on soil resources in Serbia when limited data are available. The outputs of these studies can be used for the identification of vulnerable areas on a cell-basis and for programming of protection measures. Keywords: USLE, GIS, Erosion, CORINE, Elevation zones Serbia 1. INTRODUCTION Soil erosion is one of the major causes of land degradation in Serbia. Problems caused by erosion are resulting in economic loss in agriculture and forestry sector, and may directly or indirectly pose a danger to persons or property. Prediction of erosion soil loss is important for the assessment of erosion risk and for the implementation of appropriate measures of land conservation. Nowadays, there is a number of erosion models that are empirically or physically based. Universal soil loss equation (USLE) is an empirical model developed by Wischmeier & Smith (1978) and it is a worldwide accepted method despite some limitations. In the municipality of Pirot USLE method was not used before. Inspite of this, Gavrilović model (1972) was used and some detailed studies on water erosion potential in Pirot district were conducted on smaller watersheds and tributaries of the River Nišava (Kostadinov 2003a, 2003b; Mustafić, 2008). Integration of USLE and GIS has led to a more easier and efficient soil erosion prediction and spatial distribution of soil erosion. There is a huge number of studies conducted with USLE through GIS environment (Lee 2004; Irvem et al. 2007; Dabral et al., 2008) on the different locations in the world. The advantages of GIS tools in USLE methodology are related to determination of topographic factor from DEM, use of geostatistics and to of remote sensing in determination of cover management factor. This work 93