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Bogner, C; Borken, W; Huwe, B: Impact of preferential flow on soil chemistry of a podzol, Geoderma, 175-176, 37-46 (2012), doi:10.1016/j.geoderma.2012.01.019

Preferential flow paths are thought to affect the patterns of chemical properties of forest soils. However, little is known about their influence on podzols in coniferous forests. In our study we examined how soil chemical properties of a podzol in a Norway spruce stand are affected by preferential flow.We did three tracer experiments with Brilliant Blue FCF and analyzed soil chemical parameters (exchangeable cations, pH, total C, total N and C:N ratio) of preferential flow paths and soil matrix. For statistical analysis, we used mixed-effects models to account for a hierarchical sampling of our data. We found 5.0 g kg−1 more C, 0.24 g kg−1 more N, a C:N ratio larger by 2, smaller pH values (0.16 pH units), 32% more Ca and 57% more Mg in preferential flowpaths than in soil matrix. Compared to the adjacent soil matrix, the content of Al did not differ significantly. However, 67% more Fe were found in preferential flow paths. These distinct chemical properties are probably due to root exudates, transport of solutes and dissolved organic carbon and percolation of acid soil solution from organic horizons along preferential paths.We attribute the increase of Ca and Mg to their transport via preferential flow paths after the application of lime some years ago.We conclude that a lower pH might enhance the release of Fe (and possibly Al) and thus increase podzolisation. In addition, our results show that soil liming could affect both the topsoil and the subsoil via transport of basic cations along preferential flow paths.

last modified 2016-06-25