Abstract

This study discusses advantages of combined application of radioactive soil redistribution tracer ¹³⁷Cs with other approaches for quantitative comparison of soil redistribution rates on conventionally cultivated arable slopes to morphologically similar slopes with forest belts on contour terraces. Three pairs of the case study slopes were selected all located within the territory of the Novosil experimental station (the Orel Region, central European Russia). Results of applications of soil-morphological and ¹³⁷Cs methods showed that slopes with forest belts are generally characterized by substantial reduction of soil redistribution rates. However, scatter of exact values of percentage decrease of net erosion rates between different pairs of slopes and quantification approaches was significant (11-82%). More consistent values (62-75%) were predicted by the USLE-based model. This substantial difference between predicted and directly measured values is attributed to a high degree of soil degradation prior to introduction of protective measures (reflected by the soil-morphological method) and lack of funding for maintaining the appropriate conditions of terraces and forest shelter belts after the collapse of the former Soviet Union (partly reflected by the ¹³⁷Cs technique). The ¹³⁷Cs technique overestimated soil redistribution rates as a result of high-magnitude erosion event prior to tillage mixing of a fresh fallout isotope unaccounted for by calibration models. The multi-technical approach allowed us to acquire much more detailed information on temporal and spatial variability of soil redistribution rates than is usually possible from single method-based studies.

Keywords: Soil redistribution rates, soil morphology, ¹³⁷Cs radioactive tracer, Chernobyl fallout.