LUTFI MIFTARI1*, FRAN GJOKA2, ELVIN TOROMANI2
1Directorate of Forests, Bulqiza Municipality Tirana, Albania
2Department of Agri-environment and Ecology, Agricultural University of Tirana, Kodër Kamëz, Tirana, Albania
2Department of Forestry, Agricultural University of Tirana
*Corresponding author e-mail: firstname.lastname@example.org
Soil erosion is a serious threat to soil productivity and water quality in central part of Albania, where agriculture is applied on sloping land. In some sub-watersheds of Ulza watershed soil erosion has changed the soil chemical properties, particularly phosphorus and potassium levels. About 26% of agricultural land is cultivated with maize and 18% of local farmers conduct tillage along the slope direction. Estimation of soil loss is useful in planning and conservation actions at the basin or watershed level. This study aims to compare estimated and measured soil loss values at sub-watershed level in Ulza watershed (Bulqizë). This was performed using soil loss data obtained by integrating RUSLE and GIS tools with C-factor values computed experimentally using monitoring erosion plots installed under different land cover and slope categories. The estimated rainfall erosivity (R), soil erodibilty (K), topography (LS) and land use/land cover (C) factors ranged from 135.6 to 177.3 MJ mm ha-1 h-1 y-1, 0.39 to 0.56(t ha h)/(ha MJ mm), 0.029-339.7) and 0 to 0.075, respectively. Preliminary results indicated that the estimated potential mean annual soil loss is 24.12 t· ha-1 y-1 or aproximately 17% lower than soil loss measured on the erosion plots. This means that the RUSLE model applied to Ulza watershed conditions provides an underestimation of soil loss when is applied at small scale (sub-watershed level). Therefore, in the RUSLE model is better to use the K and R factors obtained from experimental measurements instead of using emprirical models developed in other studies.
Keywords: Soil loss; RUSLE model; GIS; experimental erosion plot; Ulza watershed.