Zur Bestimmung der ungesättigten Wasserleitfähigkeit im Felde

Abstract

Remarks on the determination of the unsaturated hydraulic conductivity based on field measurements In a previous paper hydraulic conductivity — moisture tension functions have been evaluated by a field method for various layers of a fallow loess soil (grey brown podzolic soil). The aim of the paper presented here, is to demonstrate the magnitude of error when the hydraulic functions are calculated in the presence of transpiring plants, as it was done elsewhere. The error arises, because the water uptake rates of roots are added to the capillary water flux through the soil matrix. From the present investigation it becomes clear that with advancing growing stages of winter wheat and the increasing water extraction ability the error becomes more and more pronounced. The conductivity values may then be overestimated by a factor of half the power of ten as compared to the results computed from the fallow soil.