10Be and 14C data provide insight on soil mass redistribution along gentle slopes and reveal ancient human impact

Abstract

Purpose Spatial and temporal patterns of past erosional events are a useful and needed information to explain observed soil patterns in different landscapes. Soil thickness reflects the overall expression of pedogenesis and erosion. Forested soils of Northern Germany exhibit varying soil thicknesses with thin soils on crest positions and buried soils at the footslope. The aim of this study is to reconstruct the complex soil mass redistribution and soil patterns of this forested area due to different periods of erosion and stability. Methods We explored the explanatory power of both 10Be (in situ and meteoric) on a hillslope and we 14C-dated buried horizons at different depths. Results The 10Be depth profiles did not show an exponential decrease with depth. They had a ‘bulge’ shape indicating clay translocation and interaction with oxyhydroxydes (meteoric 10Be), bioturbation and soil mass redistribution (in situ 10Be). The combined application of both 10Be and 14C dating revealed progressive and regressive phases of soil evolution. Although Melzower Forest is protected (same vegetation) since the past 250 years, both 10Be clearly indicated major soil mass redistribution along the investigated catena. Conclusion A strong erosion impulse must have occurred between 4.5 and 6.8 kyr BP indicating an earlier human impact on soil erosion than previously postulated (~ 3 kyr earlier). Our findings correlate in fact with the first settlements reported for this region (~ 6.8 kyr BP) and show their immediate effect on soils. The overall soil redistribution rates in this forest are surprisingly similar to those obtained from a nearby agricultural area.

Soil erosion rates during the Holocene continuity in a forest‐steppe landscape

“…Interestingly, meteoric 10 Be showed a weak negative correlation ( R 2 = 0.35, p < 0.05; Figure 7) with the dithionite‐extractable Fe (amorphous and crystalline forms); usually, a positive correlation is observed (Calitri et al, 2021; Wyshnytzky et al, 2015). Other studies found correlations of meteoric 10 Be with the oxalate‐extractable Fe (Calitri et al, 2019; Egli et al, 2010).…”

“…Site CJ‐4 had an accumulation of 10 Be in the clay‐rich Btg to C horizons. Therefore, clay translocation seemed to have contributed to the ‘bulge’‐type distribution (Calitri et al, 2021; Graly et al, 2010).…”

“…Latitude and longitude are in WGS84 coordinates. Shielding correction includes the effects caused by mountain topography, dip and strike of the boulder surfaces extractable Fe (amorphous and crystalline forms); usually, a positive correlation is observed (Calitri et al, 2021;Wyshnytzky et al, 2015). Other studies found correlations of meteoric 10 Be with the oxalate-extractable Fe (Calitri et al, 2019;Egli et al, 2010).…”

3–4D soil model as challenge for future soil research: Quantitative soil modeling based on the solid phase

“…Gradual changes in the soil inventory are often unaccounted for, such as, the input or output of solids by wind and tillage erosion (e.g., Calitri et al., 2019, 2020, 2021; Öttl et al., 2021), or by slow moving soil creep along hillslopes (Pawlik & Šamonil, 2018). Slow changes are also caused by the movement of dissolved and particulate organic matter in the soil profile (Lehmann et al., 2021), suffusion and internal soil erosion (Aboul Hosn et al., 2018; Huang et al., 2021), and particle detachment along preferential pathways (e.g., Michel et al., 2010), and within the soil matrix from the top into the subsoil (e.g., Rieckh et al., 2014, 2015).…”

“…The information remains valid only for those soil properties that most likely do not change within several decades or centuries such as texture and mineral content. For those properties that can change relatively fast (e.g., SOC stocks, bulk density), or for which the changes could not be identified with current technologies, there is a risk that soil maps provide Gradual changes in the soil inventory are often unaccounted for, such as, the input or output of solids by wind and tillage erosion (e.g., Calitri et al, 2019Calitri et al, , 2020Calitri et al, , 2021Öttl et al, 2021), or by slow moving soil creep along hillslopes (Pawlik & Šamonil, 2018). Slow changes are also caused by the movement of dissolved and particulate organic matter in the soil profile (Lehmann et al, 2021), suffusion and internal soil erosion (Aboul Hosn et al, 2018;Huang et al, 2021), and particle detachment along preferential pathways (e.g., Michel et al, 2010), and within the soil matrix from the top into the subsoil (e.g., Rieckh et al, 2014Rieckh et al, , 2015.…”