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Kazimierz Januszek, Joanna Długa and Jarosław Socha

Abstract

Dehydrogenases are exclusively intracellular enzymes, which play an important role in the initial stages of oxidation of soil organic matter. One of the most frequently used methods to estimate dehydrogenase activity in soil is based on the use of triphenyltetrazolium chloride as an artificial electron acceptor. The purpose of this study was to compare the activity of dehydrogenases of forest soils with varied physicochemical properties using different triphenyltetrazolium chloride assays. The determination was carried out using the original procedure by Casida et al., a modification of the procedure which involves the use of Ca(OH)2 instead of CaCO3, the Thalmann method, and the assay by Casida et al. without addition of buffer or any salt. Soil dehydrogenase activity depended on the assay used. Dehydrogenase determined by the Casida et al. method without addition of buffer or any salt correlated with the pH values of soils. The autoclaved strongly acidic samples of control soils showed high concentrations of triphenylformazan, probably due to chemical reduction of triphenyltetrazolium chloride. There is, therefore, a need for a sterilization method other than autoclaving, ie a process that results in significant changes in soil properties, thus helping to increase the chemical reduction of triphenyltetrazolium chloride.

Open access

Grzegorz B. Durło, Stanisław Małek and Jarosław Socha

Abstract

An increase in frequency of weather phenomena in the Western Beskids that are disadvantageous for natural environment caused an upset of ecologic balance, especially within the scope of water management and retention. Concerns referring to forest groups maintaining their stability are fully justified, regarding that in many areas of the Beskids, there is an intensive reconstruction of stands of trees in the lower subalpine region. In turn, young generations of trees are continuously stresses, which arise from periodic shortages of precipitation within the course of the whole vegetation process. The presented work encompasses characteristics of extreme rainfall events that might have a negative impact on growth and development of Norway spruce stands in the Silesian Beskid in recent decades.

The article makes use of meteorological data from a multiannual period (1951–2010), gathered in 26 meteorological stations of the Polish Institute of Meteorology and Water Management (IMGW) in Silesian Beskid one station located in the Carpathian regional gene bank and two under canopy posts located in Wisła forestry inspectorate area. Special attention was devoted to the presence of extreme phenomena and their repeatability. The analysis of parameters of rainfall sequences was complemented with indexes determining ecological requirements of spruce, such as: Schmuck moisture indicator, Vogel-Daniels habitat dryness index and abundance of rainfall indicator developed in this study.

Results of climatological analysis confirmed that weather phenomena with, especially dynamic course may lead to destabilisation of even a properly formed and adequately developed forest ecosystem, and as a consequence, disturb stability in the natural environment. Diminishment of the index of precipitation size, which has been observed in recent years, may be one of the most crucial causes that limit the number of spruces in the stands of trees of the lower subalpine region in Silesian Beskid. The climatological analysis confirmed that during 60 years in Silesian Beskid, there were over 20 extreme weather (precipitation) episodes of different courses, intensity and surface reach, out of which at least 9 played a key role in lowering the health condition of the trees, as a consequence, it influenced destabilisation of the spruce stands in the lower subalpine region, regardless of their age or location within the area.