Methodenvergleich der Bodenfeuchtebestimmung und Messung der Infiltration in teilweise gefrorene Böden

Abstract

Fritz, H.; Ollesch, G.; Weigert, A; Schmidt, J.: Comparison of soil moisture estimation and measurement of infiltration into partly frozen soils. – Hercynia N.F. 40 (2007): 19–31.Until now field experiments to measure water infiltration into frozen or partially frozen soils are sparse. However, winter rainfall and snowmelt may cause increased surface runoff and lead to floods in northern and central Europe. Thus, in winter 2003/04 double-ring infiltration experiments were conducted on an untilled field to estimate and compare the hydraulic characteristics of frozen und unfrozen soil in situ. The cambisol at the experimental location in the eastern lower Harz mountains, which was characterised by a ploughing horizon with very high conductivity (1 · 10-3 m/s) and a low conductivity Bv horizon (2 · 10-4 m/s) did not show any differences in the experimental estimated saturated hydraulic conductivity. However, the saturation period at the beginning of the infiltration indicated a structural modification of the pore volume in the A horizon for the frozen soil conditions. Different methods to measure soil moisture at the experimental location were tested during the investigation period. It became clear that all applied methods (Watermark sensor, TDR probe, gravimetric soil moisture sampling) have a reduce suitability to precisely measure soil moisture in frozen or partly frozen soils.