Results of Medium-Term Soil Redistribution Rates in Cluj County, Romania, using 137Cs Measurements

Soil erosion represents a serious problem in Romania and there is an urgent need for better antierosional management practices, based on quantitative information about the erosion pattern and aggradation rates. The aim of the study was to quantify the medium-term soil redistribution pattern in a pasture land from the Prodaia Valley hydrographical basin, Cluj County, Romania using a theoretical conversion model for uncultivated soils. Five sampling points were considered for establishing the 137Cs concentration at the reference site and the average inventory result was 3 160 ± 247 Bq m-2 (mean ± 95% confidence interval), with a variation coefficient (CV) of 27.44%. Two downslope transects were established for sampling and cesium inventories for all sampling points ranged from 1 157 ± 101 Bq m-2 to 4 629 ± 210 Bq m-2. The spatial patterns of the 137Cs inventories showed a very good concordance with the soil redistribution rates. The net erosion rate obtained using the Profile Distribution Model was -5.8 t ha-1 yr-1 and the sediment delivery ratio was 81%. It has been obtained a lower value of the net erosion rate in the field than using conventional small erosion plots. The complex geomorphology of the study field appeared to have a significant influence on erosion or deposition rates and it could not be entirely represented by small erosion plots.