Determination of soil loss by 137Cs fallout radionuclide in Ömerli watershed of İstanbul, Turkey

Abstract

Soil erosion and sedimentation in watersheds are usually part of the information to be considered for soil and water conservation measures. Soil loss is generally estimated with models or measured with plot studies. Although fallout radionuclides (FRN) methodology provides a powerful technique for predicting the impacts of proposed land management strategies on soil erosion and sediment yield within river basins and estimates erosion based on fallout radioisotopes (Cs-137, Pb-210, Be-7) radioactivity, it is rarely used in Turkey. The aim of this study was to determine soil losses from different land use types with FRN's methodology by using caesium-137 radionuclide in selected study sites around Paşaköy (shrub) and Esenceli (rangeland) villages in the environs of Ömerli watershed. Bulk and 2 cm-depth incremental soil core samples were collected from the reference and sloping areas in both study sites. Soil losses varied from 0.49 to 23.22 t ha-1 yr-1 for shrub-covered sites and from 0.44 to 7.23 t ha-1 yr-1 for rangelands. The data show that soil loss from shrub-covered site was greater than acceptable tolerance limit (10 t ha-1 yr-1) for soils of the sites. © TÜBİTAK.