Preliminary effects of fertilization on ecochemical soil condition in mature spruce stands experiencing dieback in the Beskid Śla̧ski and Żywiecki Mountains, Poland

In recent years, there has been the phenomena of spruce dieback in Europe. Significant areas of spruce low mortality now cover both sides of the Polish southern border. We evaluated ecochemical parameters influencing the heavy dieback occurring in mature spruce stands in the Polish Carpathian Mountains. Dolomite, magnesite and serpentinite fertilizers were applied to experimental plots located in 100-year-old stands in the autumn of 2008. The experimental plots were located in the mid-elevational forest zone (900-950 m) on two nappes of the flysch Carpathians: Magura (Ujsoły Forest District) and Silesian (Wisła Forest District). The saturation of the studied soils demonstrates moderate resilience of soils in Wisła Forest District in relation to acid load and high flexibility of the Ujsoły soils. After application of the fertilizers, an increase of Mg, Ca and Mb was noted in the soil solution, determined in the overlaying highly acidic organic horizons through the ion-exchange buffering mechanism of highly protonated functional groups with high buffering capacity. Magnesium concentration increased following fertilization, presenting a potential improvement of forest growth capacity without the hazard of adverse side effects of liming. Aluminium stress in old spruce is unlikely, while trees in the control plots in Wisła Forest District may already be sensitive to aluminium stress. Serpentinite fertilization improved the supply of soils in magnesium without causing significant changes in the pH of the soil. Such changes in the pH were found in dolomite and magnesite fertilizer. © The Author(s) 2014

Usability of enzyme activity in estimation of forest soil quality

Taking into account the progressive degradation of soils it is important to assess their quality. Soil quality depends on a large number of physical, chemical, biological and biochemical properties. In the publications available, there are presented three approaches regarding the use of soil properties to estimate soil quality: (1) the use of individual properties, (2) the use of simple indexes and (3) the use of complex indexes derived from combinations of different properties. The purpose of this study was to investigate the possibility to use enzymes as indicators of forest soil quality. Experimental plots (43) were located in central Poland. The study was carried out in a number of diverse fresh forest sites. To assess the quality of forest soils dehydrogenase and urease activity and the degree of base saturation were used. One of the final conclusions point out that enzymatic activity indicates current site condition as well as the changes that occur in soil better than soil physical and chemical properties. In other words, in comparison to soil enzymatic activity, soil physico-chemical properties constitute a less sensitive indicator of soil changes

Dehydrogenase activity of forest soils depends on the assay used

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

Effects of serpentinite fertilizer on the chemical properties and enzyme activity of young spruce soils

The experimental plots used in the study were located in the middle forest zone (elevation: 900-950 m a.s.l.) on two nappes of the flysch Carpathians in southern Poland. The aim of this study was to assess the effects of serpentinite in combination with nitrogen, phosphorus, and potassium fertilizers on selected chemical properties of the soil and activity of dehydrogenase and urease in the studied soils. All fertilizer treatments significantly enriched the tested soils in magnesium. The use of serpentinite as a fertilizer reduced the molar ratio of exchangeable calcium to magnesium, which facilitated the uptake of magnesium by tree roots due to competition between calcium and magnesium. After one year of fertilization on the Wisła experimental plot, the pH of the Ofh horizon increased, while the pH of the mineral horizons significantly decreased. Enrichment of serpentinite with nitrogen, phosphorus, and potassium fertilizers stimulated the dehydrogenase activity in the studied organic horizon. The lack of a negative effect of the serpentinite fertilizer on enzyme activity in the spruce stand soil showed that the concentrations of the heavy metals added to the soil were not high enough to be toxic and indicated the feasibility of using this fertilizer in forestry

Application of the Soil Trophic Index for the mountain areas (SIGg) in the assessment of the quality of the dying spruce stands sites

In recent years, we face a massive dieback of Norway spruce stands in Poland. The cause of this process may lay in the way of their monocultural silviculture. The correct assessment of the habitat conditions and soil properties in particular is the basis of the proper management of these forest areas. The aim of this study was to verify application of the trophic soil index for mountain areas (SIGg) in the assessment of site conditions for spruce stands with different health condition. Three types of spruce stands were distinguished: degenerated, weakened and stable. In total, 32 study plots were established in following forest districts in southern Poland: Ustroń, Wisła, Bielsko, Węgierska Górka, Jeleśnia, Ujsoły and Lądek Zdrój. The SIGg was calculated on the basis of <0.02 mm fraction content, the sum of exchangeable base cations, soil acidity and the total content of N and organic C in the humus−mineral horizon. These attributes are useful to determine the potential productivity of the soils did not differentiate visibly the analyzed stand variants. The soil in degenerated and weakened spruce stands showed higher degree of acidity and less the content of base cations compared to soils of stable spruce stands. Mountain trophic soil index can be applied in the assessment of the forest sites potential. Although it does not enable to monitor the disturbances in the nutrients circulation, the detailed analysis of its components allows for precise assessment of the forest sites status

Impact of aluminium sulphate fertilizer on selected soil properties and the efficiency and quality of pine seedlings in the forest ground tree nursery

The alkalization of soil is a common phenomenon in forest ground nurseries. Liming, inadequate fertilization and the use of hard water for irrigation are the main reasons for this alkalization. The aim of this study was to investigate the effect of fertilization with aluminium sulphate on soil pH, the activity of selected soil enzymes, efficiency as well as the growth parameters of pine seedlings. The study was conducted in a forest nursery, on a plot with soil pH 6.4 in water and 5.9 in 1MKCl. Such a pH is not conducive to the production of conifer seedlings, particularly pines. Two different doses of aluminium sulphate fertilizer were applied: 740 kg ha-1 and 1110 kg ha-1. Both doses significantly reduced the soil pH, whereas soil enzyme activity did not change. The lower dose had a positive impact on the growth parameters of pine seedlings, while the higher dose led to their deterioration. We observed statistically significant differences in average primary and lateral root lengths, number of short roots, and thickness of the neck root of seedlings. One- and 2-year-old seedlings did not show symptoms of nutrient deficiency and neither did concentrations of the investigated macronutrients and selected micronutrients in needles indicate such. After applying the higher fertilizer dose, we observed a favourable change in the composition of mycorrhizae. Out of the potential seedling pathogens we found Cylindrocarpon spp., Fusarium spp., Phytophthora spp., Pythium spp. and Rhizoctonia solani of which the most frequent were Fusarium oxysporum, Pythium spp. and R. solani. Their occurrence frequency differed between the treatments used in this experiment. This study confirms the positive effects of a low aluminium dose on the performance and growth parameters of pine seedlings. However, on the basis of the conducted experiments, it is difficult to say, whether this positive effect is due to a direct action of aluminium on the seedlings or rather an indirect effect caused by lowering the soil pH, which in turn impacts on mycorrhizae composition and hence pathogen development