Tracing erosion rates in loess landscape of the Trzebnica Hills (Poland) over time using fallout and cosmogenic nuclides

Aleksandra Loba,Marcus Christl,Jarosław Waroszewski,Fancesca Calitri,Markus Egli,Marcin Sykuła,Dmitry Tikhomirov

doi:10.1007/s11368-021-02996-x

Abstract

PurposeLoess landscapes are highly susceptible to soil erosion, which affects soil stability and productivity. Erosion is non-linear in time and space and determines whether soils form or degrade. While the spatial variability of erosion is often assessed by either modelling or on-site measurements, temporal trends over decades to millennia are very often lacking. In this study, we determined long- and short-term erosion rates to trace the dynamics of loess deposits in south-western Poland.Materials and methodsWe quantified long-term (millennial) erosion rates using cosmogenic (in situ 10Be) and short-term (decadal) rates with fallout radionuclides (239+240Pu). Erosion processes were studied in two slope-soil transects (12 soil pits) with variable erosion features. As a reference site, an undisturbed soil profile under natural forest was sampled.Results and discussionThe long-term erosion rates ranged between 0.44 and 0.85 t ha−1 year−1, whereas the short-term erosion rates varied from 1.2 to 10.9 t ha−1 year−1 and seem to be reliable. The short-term erosion rates are up to 10 times higher than the long-term rates. The soil erosion rates are quite consistent with the terrain relief, with erosion increasing in the steeper slope sections and decreasing in the lower parts of the slope, while still maintaining high values.ConclusionsSoil erosion rates have increased during the last few decades owing to agriculture intensification and probably climate change. The measured values lie far above tolerable erosion rates, and the soils were found to be strongly imbalanced and exhibit a drastic shallowing of the productive soils horizons.

Highlights

The increase in soil erosion is a direct consequence of agricultural exploitation and threatens soil stability, quality and its productivity (Rickson 2014; Guzmán et al 2015; Alewell et al 2017; Golosov et al 2021)
Where E is the erosion rate (t ha−1 year−1), t is the year of sampling, t0 is 1963, X is the % reduction in total inventory with regard to the local reference value and h0 is a profile shape factor; and
The short-term erosion rates are distinctly higher than the long-term rates. This finding fits very well with the results presented in Kołodyńska-Gawrysiak et al (2018), proving that, since prehistoric times, soil erosion rates (0.39–0.57 t ha−1 year−1) have increased by a factor of almost 10 compared to the time span between the Middle Ages and Modern Times (3.7–5.9 t ha−1 year−1)

Summary

Introduction

The increase in soil erosion is a direct consequence of agricultural exploitation and threatens soil stability, quality and its productivity (Rickson 2014; Guzmán et al 2015; Alewell et al 2017; Golosov et al 2021). One of the materials most susceptible to erosion are loess deposits (Licznar et al 1981; Yang et al 2006; Zhang et al 2018; Poręba et al 2019). Loess materials are widely distributed across the world (Muhs 2013; Schaetzl and Attig 2013; Pasquini et al 2017).

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Discussion

Conclusion