Combining 137Cs measurements and a spatially distributed erosion model to assess soil redistribution in a hedgerow landscape in northwestern France (1960–2010)

Abstract

Erosion is one of the main threats to soils and is associated with numerous environmental and economic impacts. At the landscape scale, soil redistribution patterns induced by water and tillage erosion are complex, and landscape structures play an important role in their spatial distribution. In this study, soil redistribution patterns, generated by both water and tillage erosion, were estimated in the vicinity of hedges in an agricultural landscape. Two complementary methods were employed to estimate soil redistribution from 1960 to 2010: 137Cs conversion models and a spatially distributed soil erosion model (LandSoil model). Both methods determined that hedges affected soil redistribution patterns, which led to soil deposition or limited soil erosion uphill from hedges, even though soil erosion rates were consistently higher than soil deposition rates. Depending on the method, mean soil redistribution rates ranged from −15.9 to −4.7tha−1yr−1 for all sampling points, from −4.8 to 2.2tha−1yr−1 in positions uphill from hedges and from −4.8 to −11.2tha−1yr−1 in positions located downhill from hedges. The impact of tillage on soil redistribution in the vicinity of hedges was found to be higher than that of water processes because 87% of net soil redistribution was linked to tillage. This confirmed the importance of including landscape structure and working at the landscape scale rather than at the plot scale to better estimate soil redistribution in agricultural areas.