Die Verlagerung physikalisch wechselwirkender Ionen in Böden - Modellentwicklung und -kalibrierung -

Leaching of physically interactive ions in soils - Model development and calibration - A deterministic approach is presented in order to describe vertical leaching of physically interactive cations (K⁺, Na⁺, Ca²⁺, Mg²⁺). Model calibration with undisturbed and disturbed Eutric Gleysol columns under quasi-stationary conditions shows good agreement between measured and simulated concentration profiles. Interaction with the soil matrix is measured on the base of exchange isotherms (Beckett, 1964). Gapon coefficients are derived directly from the slope of the Q/I relationships. In the case of non-linearity of the exchange isotherms it is necessary to use Gapon coefficients, variable in time and space. KCl application induces K⁺ fixation in every case, which can be described by a simple diffusion approach. Leaching phenomena in one of the undisturbed columns can only be explained on the base of a dual pore system.