Using Fallout 137Cs and 210Pbex to Estimate Soil Redistribution Rates atDifferent Temporal Scales in Iranian Semi-Arid Farm Land

The present study is the first investigation of using naturally derived 210Pbex toestimate soil redistribution rates in Iran. This research assessed the applicability ofcoupling 137Cs and 210Pbex measurements to document medium-term (~45 years) andlong-term (~100 years) soil redistribution rates under semi-arid climatic condition inKouhin, Qazvin. In the field, soil conservation operations i.e. broad-base terraces andcontour farming have been established around 40 years ago. The net soil lossestimated at 4.6 and 12.3t ha-1 yr-1 for 137Cs and 210Pbex approaches, respectively. Dataon soil redistribution estimated by the use of both radionuclides were not similarreflecting that soil erosion processes in the field changed considerably due to thechange of soil management during the last decades. The results confirmed thepotential for using 210Pbex in semi-arid environments. However, the 137Cs techniqueprovided more reliable results owing to its good gamma measurement precision incomparison with 210Pbex

Using Fallout 137Cs and 210Pbex to Estimate Soil Redistribution Rates atDifferent Temporal Scales in Iranian Semi-Arid Farm Land Keywords:

Soil erosion , Fallout Radionuclides , Mass Balance Models , Kouhin , Iran