The definition of soil water potential is based on the chemical potential of homogeneous medium. The assumption of homogeneity causes many difficulties to arise when such a definition is used for the description of highly heterogeneous soil medium. Another aspect discussed here is the basic of division of a soil water potential onto additive parts (pressure, gravitational, thermal etc.). It has been shown here that this division can be done when only one parameter of state changes, otherwise it is only approximation with possibly high error.
The aim of the research was to analyse the impact of soil water potential on the concentration of aluminium and selected mineral nutrients in soil solution. Soil acidification is a natural process accelerated by agriculture, and one of the most important factors limiting crop production worldwide. Concentrations of aluminium and selected mineral nutrients in solutions obtained from soil at initial pH 4.2 and after liming at various soil water potential were measured in centrifuged soil solution. Our results showed a significant gradual increase in the concentration of Al and most of mineral nutrients (Ca, Mg and P) with decreasing soil water potential from −3.5 kPa to −0.205 MPa. The results are important in the evaluation and interpretation of plant response to aluminium toxicity when accompanied by changes in water availability.
At present time there are materialized simultaneously two viable tasks in the area of water management in the European Union countries. The first is the realization of the tasks given in Water Framework Directive and the second one is the task of the process of evaluation and strategy of the expected inevitable climatic changes. The realization output of the first task will be presented by the water management plans which are being prepared and which are going to take into consideration influence of the climate changes on the water resources or the water balance in the catchment. On that account the balance of really measured and recorded data from the last ten years can evidently help to judge possible hydrologic cycle and balance of water management in the further decades. Taking everything this into consideration we are able to assess the role and responsibility of the participants in the balance of requirements to maintain sustainable water exploitation in the catchment areas in Slovakia in the period of time from 1995-2005.
The paper presents statistical, geostatistical and fractal analysis of variability of topsoil water pontent along a loess hillslope. Spatial dependence of topsoil water content was observed on studied sites. On a site with plants, the range of spatial dependence was smaller than on a site without plants. Fractal dimension showed that topsoil water on a site with plants was more randomized than on a site without, il.
The aim of the study was to examine the usefulness of simple pore shape indices for the classification of soil structure with respect to two main groups of soil macropores (fissures and cavities). The samples were taken from various soils of SE Poland: Mollic and Eutric Leptosols, Eutric Regosol, Haplic Phaeozem, Haplic and Stagnic Luvisols, and Sapric Histosol. The research was performed on 81 polished blocks using image analysis. First, the soil samples were classified into five structural groups: mixed, fissure, nearly fissure, cavity and nearly cavity. Morphometrical analysis provided shape indices CIRav, ELGav, and their coefficients of variation V(CIR), V(ELG). They enabled the group of fissure structures to be distinguished from the groups of mixed, cavity and nearly cavity structures. The research may contribute to the creation of an objective method for recognising soil structure in respect to the main soil structure types: mixed (fissure-cavity), fissure and cavity structures.
In the present study soil-water coefficients ksi were determined and evaluation of the influence of soil sucking pressure on the actual yield was carried out. Relations between these coefficients and soil sucking pressure in the root zone are used for the calculation of actual evapotranspiration or actual yield neglecting evaluation of the influence of evapotranspiration on yield.