© by PSP Volume 20 – No 8. 2011 Fresenius Environmental Bulletin 1910 ASSESSMENT OF SOIL EROSION POTENTIAL BY THE USLE METHOD: CASE STUDY, REPUBLIC OF SRPSKA - BiH Radislav Tosic 1 , Slavoljub Dragicevic 2, *, Stanimir Kostadinov 3 , and Nada Dragovic 3 1 Faculty of Natural Sciences, M. Stojanovića 2, 78000 Banja Luka, Republic of Srpska 2 University of Belgrade, Faculty of Geography, Studentski trg 3/3, 11000 Belgrade, Serbia 3 University of Belgrade, Faculty of Forestry, Kneza Viseslava 1, 11030 Belgrade, Serbia ABSTRACT Soil erosion is a global problem, with severe conse- quences for the environment, human society and economy. In most cases, this process is caused by natural forces, but some human activities also contribute to soil erosion. The USLE is an erosion model which estimates average soil loss that would generally result from splash, sheet and rill erosion. Use of USLE has been extended as a useful tool for predicting soil losses and planning control practices by the effective integration of GIS-based procedures for esti- mation of factor values on a grid cell basis. In this paper, as a result of GIS layers-overlapping is a map of soil erosion for the study area of Republic of Srpska, and estimation soil erosion rate. The results will be taken into considera- tion during analysis of choosing the simple and efficient erosion prediction model for agricultural resources man- agement and land planning which would be used in Re- public of Srpska. We obtained an average of 5.13 t/ha/year of potential erosion in the study area, and 52.46 % of the territory had an erosion rate of <2 t/ha/year. The estima- tions of soil loss of >15 t/ha/year are inherent in 7.28 % of the study area. The basic objective of this paper was to provide a regionalisation of the territory of Republic of Srpska according to the level of the soil erosion risk. This is the first version of the soil erosion risk map with the USLE methodology in Republic of Srpska. KEYWORDS: Soil erosion, erosion potential, USLE, GIS, mapping. 1. INTRODUCTION Soil erosion is a global problem with severe conse- quences for the environment, soil degradation, water qual- ity [1], agricultural production, and human sustainability [2]. Many models for soil erosion estimation have been devel- oped, and empirical models are still widely applied in many countries. In a previous research in the Republic of * Corresponding author Srpska, the intensities of erosion processes were estimated on the basis of Erosion Potential Method [3], still in use in all countries originating from the former Yugoslavia. The computational and data requirements for such models are usually lower than for conceptual and physically based models, and empirical models are often criticized [4]. In practice, the Universal Soil Loss Equation (USLE) has been the most widely used model for soil loss predic- tion. Indeed, it was initially developed for usage in agri- cultural context [5, 6]. Recently, the USLE has been suc- cessfully used at national, regional and watershed level [7, 8]. Using USLE for a greater scale than the field scale re- quires the usage of GIS-based procedures to determine the factor values for predicting soil erosion in a grid cell [9]. When used in conjunction with raster-based GIS, the USLE model can isolate locations of erosion on a cell by cell basis, determine the role of individual variables on the rate of erosion, and identify the spatial patterns of soil loss within a watershed [10]. This method is the most effective way to predict soil erosion processes and their effect by using GIS, but USLE is limited to estimating gross ero- sion rates, deposition along hill slopes, depressions, val- leys or in river channels. The study presented here is the first version of the soil erosion map with USLE methodology in Republic of Srpska. This analysis is especially important as an attempt to categorize countries according to their levels of soil erosion risk and natural hazards [11-13]. 2. MATERIALS AND METHODS 2.1. Study area The Republic of Srpska is a political and territorial subject (Entity) of the internationally recognized state of Bosnia and Herzegovina. The study area is located in South-East of Europe within a location of 42°33'19" and 45°16' 34" N and 16°11'06" and 19°37'44" E; its area is 25,053 km 2 , having around 1400000 inhabitants. The whole area of Republic of Srpska belongs to the large mor- phologic clusters: Panonic region, Mountain – valley re- gion and Adriatic region. The terrain is ranging from 80 to 2368 m above sea-level.