A BRIEF OVERVIEW OF SCIENTIFIC RESEARCH CAURRENTLY CARRIED OUT BY FOREST SOIL HYDROLOGISTS ASSOCIATED WITH THE CENTRE FOR SCIENTIFIC TOURISM IN SLOVAKIA

1. Measurement of Saturated and Unsaturated Hydraulic Conductivity Through Solute Transport Experiments (in co-operation with the UC Riverside)

Transport of chemicals through soil may be accurately predicted only if the hydraulic properties of the soil are thoroughly understood. Models range from those based on the physics of flow to those which essentially are curve-fitting algorithms with empirical coefficients. Deterministic approaches to the problem have repeatedly failed; a user-friendly, accurate model of these properties which is applicable to a wide variety of soils remains an elusive goal. This paper presents the results of experiments designed to test a new model which predicts hydraulic conductivity as a function of the velocity distribution of a solute moving through a soil system at saturation. Presently this model is applicable in the gravity flow regime. Laboratory experiments were performed to establish the range of validity of the model in its current form, as well as that of the stochastic-convective hypothesis underlying the method. Numerical methods will be used to demonstrate the relationship between theory and experimental results.

Stochastic-convective vs. Convective-disperive models (Jury et al. 1991)

2. Monitoring of physiologically available soil water in sub-mountain beech forests

Distribution of matrix potentials under a beech forest over a three-year period

Project has been based on the monitoring of soil matrix potential in a beech forest over a period of 36 months. The results indicate that the transpiration decrease had been conditioned by low matrix potential values around -700 hPa.

3. Interactions between soil and plants in forested areas

Project deals with the interaction between plants as parts of forest ecosystems and the changing environmental conditions in the forested areas. As the majority of such interactions include forest soils as a medium where important processes play out, special attention is being paid to new areas of research, such as water flow irregularities and instabilities, chemical instabilities and ground flora response to extreme weather patterns and its influence on soils.

Different courses of soil water content under beech stands featuring various densities

4. Transpiration of the ground flora

Comprehensive soil physical analyses and field measurements were carried out at the Ecological Experimental Stationary Station Kremnické Vrchy Mts. from 1994 till 1995 with the objective to quantitatively assess the share of soil moisture potentialy available from deeper soil layers on the tranpiration of the herbal layer consisting mainly of sedge Carex pilosa. The maximum upward flux measured during the two consequitive years was 0.03 mm per day from the depth of 50–70 cm to the topsoil. That amount covered just some 5–10 % of the daily volume of water transpired by the ground flora.

Experimental station Kremnické Mts. where the relevant research has been carried out in areas with reduced stand densities

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