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The study analyses the growth of beech seedling fine roots and their development in the first five years. The research plots were established in 1997-2003 in community forests of Starý Plzenec (Western Bohemia, Czech Republic). The data are based on annual reviews of beech samplings extracted from surveyed plots. The whole root volume as well as the fine root volume is significantly (on a 95% significance level) growing during the first years after outplanting and there is not any disruption of growth immediately after outplanting.

In the locality Hnilé Blatá (the High Tatras Mts.), the structure was measured of root branches in the windthrown spruces (Picea abies [L.] Karst.). After cleaning the root plates, the number, diameter, and length of individual root branches were measured. Individual root branches were classified into twelve diameter classes - according to their diameters measured in the middle of the root branch length. We found out a high frequency of the root branches in the first three root-diameter classes; the values of the average frequency of root branches smoothly declined with their diameters increasing. We found out the lowest mean values of the root branch length in the first two root diameter classes. However, the values of total average length of root branches were the highest in the first root diameter class and these values continually decreased with increasing values of the root branch diameter. On the basis of the high values of root frequency and of total root length in the thinnest root-diameter classes, it seems that the spruce trees growing in gley soil form a similar root structure as those growing in podzolic brown soil.

The effect of 24-epibrassinolide and 28-homobrassinolide on seed germination and seedling growth of radish (Raphanus sativus L.) was studied under cadmium toxicity. The impact of brassinosteroids (BRs) on free proline levels and the activity of antioxidant enzymes catalase (CAT; EC 1.11.1.6), peroxidase (POD; EC 1.11.1.7), superoxide dismutase (SOD; EC 1.15.1.1), ascorbic peroxidase (APOX; EC 1.11.1.11) and guaiacol peroxidase (GPX; EC 1.11.1.7) in radish seedlings under Cd toxicity was evaluated. The effect of BRs on the activity of ascorbic acid oxidase (AAO; EC 1.10.3.3) and lipid peroxidation in radish seedlings challenged with Cd stress was also investigated. BRs supplementation alleviated the toxic effect of the heavy metal and increased the percentage of seed germination and seedling growth. Out of the two substances, HBL was found to be more effective than EBL in stress alleviation. HBL (3µM) alleviated the toxic effect of the heavy metal and increased the percentage of seed germination by 57% over Cd and 20% over unstressed control. Similarly supplementation of HBL (3µM) caused an increase of 156%, 78% and 91% in length, fresh weight and dry weight of seedling, respectively, over Cd treatment alone. The amelioration of seedling growth by BRs under metal toxicity was associated with enhanced levels of free proline. The activities of antioxidant enzymes CAT, SOD, APOX and GPX were increased in the seedlings from treatments with Cd along with BRs. Brassinosteroid treatment reduced the activity of POD and AAO in heavy metal stressed seedlings. Lipid peroxidation induced by Cd was found reduced with the supplementation of BRs. The results obtained in the study clearly indicated the ameliorative influence of brassinosteroids on the inhibitory effect of Cd toxicity.

Avian tuberculosis (ATBC) is a significant cause of morbidity and mortality in birds in zoos and breeding establishments. The primary sources of Mycobacterium avium subsp. avium (MAA) of serotypes 1, 2 and 3 are infected animals (esp. birds), who shed MAA in different ways and thus contaminate the environment. The first aim of this work was to compare the efficiency of the diagnostic methods that are routinely used for the diagnosis of ATBC (skin test, serology and culture of faeces and eggs) in naturally infected hens with different levels of infection. The second aim was to determine the excretion rate of MAA in faeces and eggs. The tuberculin skin test gave a positive result in nine (42.9%) infected hens of which four (57.1%) and one (14.3%) were heavily and slightly infected hens, respectively. A positive serological response to MAA-b antigen (water bird isolate of serotype 1) was observed in five (23.8%) and to MAA-p antigen (pig isolate serotype 2) in seven (33.3%) hens. No correlation between serological and skin-test data was found. The results show that both techniques, serological and skin-test data are inadequate for the diagnosis of ATBC. In consecutively euthanized hens, with heavy infection and tuberculous lesions, serological positivity was significant (P < 0.05) in comparison with slightly infected hens lacking tuberculous lesions. Faecal culture detected MAA in 50 (29.8%) of 168 samples collected for eight days before euthanasia. MAA excretion in faeces was intermittent, but significantly (P < 0.01) higher in heavily infected hens. No mycobacteria were detected in any of the 43 examined eggs, which implies that the shedding of MAAand/or transmission of ATBC through eggs may not be frequent events.

The present paper is the first contribution from the biomass quantification series which is realized by Forestry and Game Management Research Institute in the Krušné hory Mts. (Northern Bohemia). This study is aimed at blue spruce substitute stands. Research was done within the blue spruce experiment Fláje II in the Krušné hory Mts. (800 m above sea level in the spruce forest vegetation zone, acidic category). Results showed that the aboveground biomass of the investigated substitute blue spruce stand without thinning amounted to approximately 56 thousand kg of dry matter per ha at the age of 22 years. Wood and bark of branches are the most important parts of the aboveground biomass (ca 40%). Needles and stem wood accounted for approximately 26 and 28% and stem bark only for 6%. At the age of 22 years, the investigated substitute blue spruce stand accumulated: N - 336 kg, P - 28 kg, K - 138 kg, Ca - 159 kg, Mg - 28 kg per hectare. Thinning with the consequent removal of aboveground biomass (54% of trees, 40% of basal area at the age of 16 years) represented a loss of ca 8.7 thousand kg/ha of total biomass, which contained 53 kg of N, 5 kg of P, 22 kg of K, 26 kg of Ca and 4 kg of Mg. The removal of biomass in areas previously degraded by acid deposition may result in the deficiency of Ca and Mg because of their low content in forest soil. On the other hand, thinning supported the faster growth of trees left after thinning and consequently faster biomass and nutrient accumulation.

Microbial activities and counts of microorganisms were monitored as a part of research projects at 11 localities on arable land of different soil types during the years 2002-2006. The counts of microorganisms (total bacteria count, actinomycetes, micromycetes, Azotobacter, oligotrophic and spore-forming bacteria) and microbial activities (respiration, ammonification and nitrification tests) were evaluated using summary statistics, analysis of variance and correlation coefficients. The average counts of microorganisms corresponded with usual counts of microbes in arable soils. There were only some differences among localities in Azotobacter counts. Soil respiration is very often used as an indicator of soil microflora activity. Average values of basal respiration were slightly lower (0.45 mg CO₂ /h per 100 g dry soil) than usual values, potential respiration with glucose (G) or with ammonium and G (NG) responded to usual values (average G 4.27, NG 9.53 mg CO₂ /h per 100 g dry soil). All activities (except actual ammonification) were higher in spring season, but the differences were not significant. There were significant differences in correlation coefficients among the selected criteria; 66% from the total number of correlation coefficients were non-significant, 34% were significant (13% of them was at the significance level 0.05, 10% P < 0.01, and 11% P < 0.001).

In the present study and research work, land suitability evaluation (qualitative classification) was made for the Bilverdy research station of the Islamic Azad University in East Azarbaijan for wheat, barley, alfalfa, maize and safflower. The Simple Limitation Method (SLM), the Limitation Method regarding Number and Intensity (LMNI) and the Parametric Methods (PM) such as the square-root and the Storie methods were used. The landscape, climate and soil and characteristics that influence suitability of the land for particular crops have been combined according to the adopted methodology. Economic factors were excluded and moderate level of management was assumed. The results of different methods show that the most important limiting factors are climate, pH, organic matter (OM), gravel, salinity and sodicity, taken either alone or in combination. For safflower, the cation exchange capacity (CEC) can be added to these factors. Evaluation by the SLM and LMNI methods result in similar suitability classes, which confirms previous findings by other researchers for the same crops. However, in many cases the use of parametric methods, especially the square-root method, turned to be more realistic in distinguishing separate suitability classes. This study not only compares different methods and their results but also evaluates the suitability of the study area for particular crops. According to the square-root method, the area can be recommended as marginally suitable for cultivation of wheat, barley, alfalfa and safflower and is expected to yield about 40-65% of optimal production.

Production of raw wood material and its regulation has a great ecological and economic importance in every country. The aim of the paper is to analyze the prospective production of raw wood with respect to the expected basic tree species composition and assortment structure on an example of long-term development of selected indicators of forest condition in Slovakia. For this analysis we used data on the area, growing stock and planned decennial timber felling in the forests of Slovakia in 1980, 1996 and 2003. The production potential of forests was evaluated on the basis of the annual perspective allowable cut by 2020, from which the prospective production of assortments was derived using the models of assortment yield tables of tree species. The results show that in the forests of Slovakia there is an about half proportion of coniferous and half proportion of broadleaved tree species, very good structure of growing stock as well as its trend in the last years. Production of raw wood assortments for industrial processing for the years 2010-2020 is limited by the volume 6.3-6.4 mil. m³. About one half of this volume comes from coniferous and the other half from broadleaved tree species. For coniferous tree species the proportion of spruce and fir is 87% and for broadleaved tree species the proportion of beech and oak is 80%. For coniferous tree species sawmill assortments have a decisive, almost 70% proportion. Regarding broadleaved tree species, pulpwood assortments with 47% proportion prevail, although with 11% the highest quality assortments for the production of veneer from beech and oak are also significant.

Wild potato species (genus Solanum, section Petota) represent a tremendously diverse gene pool which is traditionally utilized as a source of diverse traits for potato breeding. Abiotic and biotic stress tolerance and resistance belong to the most frequently utilized traits of wild species in potato breeding programs. This review provides an introduction to the taxonomy, centre of diversity, genetic characteristics, evolution and important tolerance and resistance traits of wild potatoes and their use for potato breeding. The review has been written for readers who are interested in the problems of finding and utilization of new resistance genes from the wild genetic resources.

The objective of this paper is to evaluate the contents of CF, NDF, ADF and ergosterol in the forage of Fistulolium, Dactylis glomerata and Arrhenatherum elatius from stands harvested at the end of the growing season. The contents of CF, NDF and ADF were analysed using the ANKOM Fibre Analyzer instrument. The ergosterol content was analysed by the HPLC method. The lowest CF content was in the Festulolium forage matter (26.8%). Conversely, the highest content was in the Arrhenatherum elatius forage (30.2%). The CF content gradually increased during autumn from 28.0% to 29.4%. Likewise, the NDF and ADF contents were lowest in Festulolium (58.3% and 32.3%, respectively). The highest NDF content was in Arrhenatherum elatius (60.5%). The ADF contents in Arrhenatherum elatius and Dactylis glomerata were comparable (35.9% and 35.1%, respectively). The NDF content increased during autumn from 56.4% to 62.0% and ADF content from 32.8% to 36.4%. The ergosterol content suggests a lower infestation of the Festulolium forage by fungi. While this content in the Festulolium forage was 94.9 mg/kg of dry matter (DM), in the Dactylis glomerata forage it was 136.7 mg/kg DM and in the Arrhenatherum elatius forage 139.9 mg/kg DM. Forage samples taken in December contained ergosterol on a level of 248.6 mg/kg DM. The species under study and the time of use in autumn exhibited a statistically highly significant effect (P < 0.01) on the contents of CF, NDF, ADF and ergosterol in the forage matter.

The results of research on the production of raw timber assortments for the stands of poplar clones Robusta and I-214 in Slovakia are presented in this paper. Models of assortment yield tables were constructed, separately for each clone, in dependence on the yield class and stand age. The construction was based on the models of yield tables, stand assortment tables, models of external quality and damage to stems. Robusta clone produces by about 15-20% higher proportions of the highest quality assortments than I-214 clone. I-214 clone produces faster and higher proportions of average- and below-average quality assortments.

The silver fir was planted under mountain conditions in order to reveal its response to the addition of finely ground rocks (limestone and amphibolite) mixed with soil into the planting holes. The results document that the increments of the plantations fertilised with amphibolite were higher by 25% on average than those of the control plantations while the increments of the plantations treated with dolomitic limestone were lower by 13%. Generally, as concerns both the plantations with the application of ground rocks and the control ones, the development of the fir plantations in 1994-2007 is considered successful. As the damage by climatic stresses has gradually diminished, the number of dead trees has been decreasing and the height increments have been increasing in the last years, therefore a positive development is to be expected also in future.

Seeds are the primary sinks for photosynthates during reproductive growth. Variation in light intercepted during and after seed initiation has been found a major environmental determinant of soybean [Glycine max(L.) Merrill] seed size. We investigated the influence of light enrichment and shading on seed growth rate, effective filling, cotyledon cell number, cell volume and endogenousABA concentrations of cotyledons/testas during seed filling of soybean. Evans, an indeterminate Group 0 soybean, was subjected to light reduction and enrichment treatments from the beginning of pod formation until final harvest for two years inMassachusetts. Higher rates of seed growth, greater seed dry weight, and higher cotyledon cell number were all observed with light enrichment. There was a reduction in seed growth rate and cotyledon cell number, along with a significant lowering of endogenousABA levels in testa and cotyledon with shade. The level ofABAin cotyledon during seed development was significantly correlated with seed growth rates only under shade treatments. Both the growth rates and seed filling duration were influenced by variation in light interception by the soybean canopy. The effects of varying light treatment on seed size, within one genotype, were most likely due to the differences in seed growth rate and cotyledon cell number.

The effect of three seedling treatments: T₀, normal germination; T₁, cotyledons removed; T₂, cotyledons removed 5 days earlier than in T₁; and two phosphorus levels (P₀ and P₃₀) on nodulation and nodule function in soybean [Glycine max (L.) Merr.] were investigated in nutrient solution culture. The number of nodules formed at P₀ was in the order T₂ > T₀ > T₁, but it was T₀ > T₂ > T₁ at P₃₀. Nodule dry weight per plant had the same tendency as the nodule number. Nodule size (dry weight per nodule) in seedlings ranged from 0.601 to 1.089 mg in the order T₀ > T₁ > T₂, regardless of P level. For example, nodule size in T₀ was larger by 86% and 52% than T₂ at P₀ and P₃₀, respectively. Furthermore, regardless of P level, a specific acetylene reduction activity (ARA, µM C₂H₄/h/g nodule) increased with P content in seedlings, but no significant difference was found (P < 0.05). Leghemoglobin (Lb) content was not significantly affected by P level; however, seedlings (T₀ and T₁) significantly affected the Lb content per unit plant biomass (P < 0.05). All these results suggest that seedling P content plays a key role in nodulation and nodule function of soybean.

In the present study the most outstanding anatomical findings of the heart of a giraffe are described. Two papillary muscles were found in the right ventricle, namely magnus and subarterial. There were no papillary parvi muscles. The supraventricular crest gave insertion to various tendinous chords. These chords fixed the angular cusp of the right atrioventricular valve. The pectinate muscles were better developed in the left auricle than in the right one. Within the left ventricle two big papillary muscles were found as well as a notorious septomarginal trabecula. The left coronary artery irrigated the majority of the heart's territory. It gave origin to the interventricular paraconal branch and to the circumflex branch. The latter gave off the branch of the left ventricular border and the interventricular subsinosal branch.

The Velvet Revolution in November 1989 in the former Czechoslovakia opened the way to the renewal of the democratic political system. One of the most visible aspects of the Czech political development consisted in the renewal of the essential functions of elections and political parties. On the local level, however, the political process - as well as in other post-communist countries - continued to be for a long time influenced by the remains of the former centralized system wherein the local administration used to be subjected to the central state power. Municipal elections took hold in these countries, however, the local government remained in the embryonic state and a certain absence of real political and economic decision-making mechanism on the local level continued to show. The public administration in the Czech Republic had to deal with the changes in the administrative division of the state, the split of the Czechoslovak federation as well as the fragmentation of municipalities whose number increased by 50 percent. Decision making mechanisms on the local and regional level were suffering from the incomplete territorial hierarchy of public administration and from the unclear division of power between the state administration and local administration bodies. Only at the end of the 1990s, the public administration in the Czech Republic started to get a more integrated and specific shape. Citizens participation in the political process represents one of the key issues of representative democracy. The contemporary democracy has to face the decrease in voter turnout and the low interest of citizens to assume responsibility within the political process. The spread of democratising process following the fall of the iron curtain should not overshadow the risk of internal weakness of democracy. The solution should be looked for in more responsible citizenship and citizens political participation. The degree of political participation is considered (together with political pluralism) to be the key element of representative democracy in general terms, as well as of democratic process on the local and regional level. The objective of this paper is to describe the specifics of citizens local political participation in the Czech Republic and to show the differences between rural and urban areas. The paper concentrates on voting and voter turnout but deals also with other forms of citizens political participation.

More than 1,300 seedlings of European plum originating from crossing combinations with at least one parent showing hypersensitivity resistance against PPV were analyzed for their reaction to artificial inoculation with PPV using the double grafting method with virus infected interstem. It was shown that the hypersensitivity resistance against the virus is a phenotypically quantitative trait. The different kinds of symptoms observed in the test system, which contribute to the hypersensitivity resistance, range from weak necrosis on the leaf blade and on the stem to the death of the whole young shoots. A hypersensitivity index was developed which helps to determine the degree of hypersensitivity resistance of an individual genotype. Its use is strongly recommended as selection tool in breeding for hypersensitivity resistance.

Humus forms dynamics and characteristics of different forest sites were studied in the area of Smrčina Mt. in the Šumava National Park territory. The study was performed in vital Norway spruce forest, dead Norway spruce forest (bark beetle Ips typographus infestation) and on a clear-cut area (site conditions were comparable for all three plots). The amount of surface organic matter was not affected by forest decline or by clear-cut (95.5 t/ha, 73.1 t/ha and 100.2 t/ha, respectively), pH being comparable (between 2.3 and 3.2 pH KCl). A slight favourable effect of grass litter on pH increase was obvious; higher leaching of bases occurred in lower horizons. Nitrogen losses were detected from the L + F horizons, falling from 1.93-1.83% (living stand) to 1.73-1.83% (clear-cut area). Higher ammonia production was documented in substrates (F and H horizons) from the living stand (from 263 and 103 mg/kg before incubation to 610 and 248 mg/kg after incubation - nitrogen content in ammonia form), and higher nitrification rates (nitrogen content in nitrate form) were recorded on the clear-cut area (103 and 80 mg/kg to 153 and 87 mg/kg) and especially in the dead stand (160 and 93 mg/kg to 216 and 139 mg/kg). Respective values for the living stand increased from 52 and 61 mg/kg to 119 and 84 mg/kg. Respiration activity, both potential and basic, was more balanced, indicating more intensive dynamics in the case of dead stand and clear-cut area.

The paper summarizes the results of long-term measurements of soil temperature. The measurements were performed at two depths: 5 cm and 20 cm, on a series of five experimental plots with different stocking. The temperature of soil in the submontane beech forest at the Ecological Experimental Site (EES) Kremnické vrchy Mts. reached maximum values in August, minimum ones in February. The obtained data were processed using t-test and regression analysis - to evaluate the influence of soil temperature at the discussed soil depths on the biomass production in plants. An important influence of this factor was confirmed at both depths.

This paper deals with large-scale mountain forest decline in the Šumava National Park. The changes in biotic and abiotic properties of forest sites follow the tree layer disintegration. Changed microclimatic conditions such as intensity of irradiance, moisture and temperature of the top holorganic layers together with altered development of ground vegetation could strongly affect the values of microbiological respiration activity and the rates of nitrogen mineralization and nitrification. Soil substrates, built of organic mater, located on stony locations, are endangered by introskeletal erosion. This paper compares these features in pairs of research plots, consisting of dead or cut forest and of living stand. According to the results of this study, higher rates of organic matter decomposition, transformed dynamics of nitrogen and other nutrients and possible nutrient leaching from soil solutions were demonstrated in the forest floor under declined spruce stands. The extent and seriousness of these adverse processes for forest soils are strongly site dependent.

The objective of the paper is to assess the effects of amphibolite powder (waste from a dust removing process in a rock pulveriser) and Silvamix slow release fertiliser on Norway spruce plantation in the harsh physical environment of the Jizerské hory Mts. The plantation characteristics such as mortality, annual height increment, stem base diameter, crown diameter and nutrient analyses are evaluated. A nine-year-long period of observation is summarised. The effects of both the forms of chemical amelioration seem to be positive and statistically significant. The benefits of the amelioration expressed in absolute figures have been easily observable until now. Recently, the importance of these benefits has decreased after the adaptation of planted trees to the mountain site and natural acceleration of their annual increment.

Restoration of forest soil character after the change of agricultural land use has not been studied yet despite the large areas reforested since the late 40ies of the last century. This process takes place throughout Europe to an increasing extent at present. The reformation of forest soils was studied in the area of Český Rudolec town: Natural Forest Area 16 - Czech-Moravian Uplands, altitude 600-630 m a.s.l., bedrock is built of granites and gneisses, soil type is Cambisol, forest site type 5K1. The process of restoration of a new humus form was analysed in plantations of American red oak (Quercus rubra), Swedish birch (Betula pendula), European larch (Larix europea) and Norway spruce (Picea abies), the site was homogeneous. The particular tree species accumulated 12.81, 13.81, 46.57 and 44.76 t/ha of surface organic matter during the last 30-40 years, these values are typical of forest sites at lower and middle altitudes and corresponding tree species composition. The effect of broadleaved species and conifers was markedly different, in the first case pH in KCl ranged 3.8-3.9 (mineral soil) and 3.5-5.2 (holorganic horizons), being 3.5-3.8 (mineral soil) and 3.1-5.1 (holorganic layers) for the conifers. Visible effects of the particular tree species were also evident in the soil adsorption complex and in the contents of plant available and total nutrients. The results can be summarised and generalised: - the forest soil character is reformed at lower and middle altitudes in a relatively short time from the aspect of surface humus accumulation and basic soil chemistry (30-40 years), - birch exhibited the best revitalisation effect among the studied species, - American red oak and Norway spruce humus accumulation potentials were different although the soil chemistry was comparable, - Norway spruce did not show a remarkable degradation effect until now, - on the contrary, European larch appeared as a site degrading species.

Forest management in the Czech Republic (CR) was not shaped in the environment of natural forests but in the territory that was influenced by unregulated felling and animal grazing for a long time. Hence the fear for sustainable and balanced benefits from forests endangered by long-term uncontrolled exploitation was legitimate. Almost after three centuries of application of the sustainability principle, forests are considered not only as a source of renewable wood raw material but also as a tool of the environment formation. Mountain forests are an important landscape component of this country. They are an object of specific importance from the aspect of natural environment conservation, stabilization of natural processes and general landscape homeostasis. In addition, they fulfil a number of production and non-production functions. Cardinal elements of sustainable forest management in the CR conditions are as follows: management of the forest as an ecosystem, i.e. transition from exclusive care of forest tree species and their stands to care of the whole forest ecosystems; restructuring (conversion, reconstruction) of damaged and declining forests; optimum (species, genetic, spatial, age) structure of forest ecosystems differentiated according to site conditions and management targets; differentiated transition from general management to group or individual methods; utilization and support of spontaneous processes such as natural regeneration, competition and other principles of self-regulation. The above cardinal elements of sustainable forest management are applicable to forests of the CR in general, but their importance considerably increases in mountain forests where many species survive on the margin of subsistence. Moreover, mountain forests of CR have been heavily destroyed by anthropogenic factors, especially air-pollution ecological stresses, during the last three or four decades.

The paper proposes a method of assessing the potential risks of the future development of stands in relation to a climatic change. To assess risks of the future development of a stand simple point scales have been worked up based on primary properties of a site and a stand according to data of the forest management plan (FMP). In assessing the health condition, the risk of damage to stands by Armillaria sp. in the felling age was evaluated on the basis of a present attack by Armillaria sp. and also defoliation of the crown primary structure assessed during a simple field examination. The evaluation was carried out in the region of the Křtiny Training Forest Enterprise (TFE) Masarykův les, ranger district Proklest, in 2002. The study was conducted in 118 Norway spruce stands aged more than 20 years. The majority of evaluated stands ranked among the category of high and medium risk from the viewpoint of site and stand risks and among the category of high Armillaria sp. attack.

This study aims to investigate the changes in isotope ratios in foliage and soils of the two spruce forests [Picea abies (L.) Karst.] differing greatly in their atmospheric N deposition and climatic conditions. As expected, both N concentrations and ¹⁵N values in both needles and litter were found to be significantly higher in the Solling stand (N-saturated) compared to the Hyytialä stand (N-poor). For the N-limited site (Hyytialä plot), a typical vertical gradient of the soil ¹⁵N-enrichment (both in organic and mineral soil) was observed. The N-saturated site (Solling) differs from the N-limited site (Hyytialä) with respect to the ¹⁵N abundance trend in organic layer. In the upper organic layer up to O-f horizon, i.e. mor layer (0-3.5 cm depth) of Solling plot, there is almost a trend of slight soil ¹⁵N-depletion with increasing depth, and then there is a ¹⁵N-enrichment from O-h horizon (humus layer) of organic layer to mineral soil horizons. This is explained by the presence of prominent NO₃^- leaching at this plot

Precision farming is a very fast developing form of the Farm Management System, especially in crop production, in whole world and in our country as well. There, it is adopted since the second half of the 90s of the 20th century. The system of data collection, analysis, presentation and application of information in precision farming is reaching over the possibilities of their use by common farmers or agricultural companies. Service companies in this case play a very important role as an executor of exacting analysis, data collection and their presentation. Management zones present simplification of the difficult operations and recommendations including economic calculations for the common user involved in the precision farming management.

The development of fish assemblage in a restored river backwater (Kurfürst backwater, Morava River, Czech Republic) was monitored over a six-year period from its restoration. The structure of fish assemblage remained similar throughout the years. Species richness of adult fish increased from twelve species during the restoration to 20 after it. Initially steady fish abundance (mean 52.3-98.1 inds/ha) and biomass (mean 5.8-7.6 kg/ha) increased significantly in 1999 five years after restoration (576.9 inds/ha and 23.3 kg/ha, respectively). The main resident species were pike Esox lucius, roach Rutilus rutilus, rudd Scardinius erythrophthalmus and perch Perca fluviatilis. High abundance of bleak Alburnus alburnus and chub Leuciscus cephalus was related to their spring spawning period. The structure of the 0+ fish assemblage was similar throughout the years, with chub and bleak prevailing during the restoration, and roach, chub and rudd after it. The number of 0+ species increased from seven to 17. The monitoring documented that the restoration could be considered as beneficial for the fish assemblage. Habitat development of the backwater is likely to influence its current value as a refuge, spawning site and nursery for local fish populations.

This study aims to investigate the changes in isotope ratios in foliage and soils of two Norway spruce (Picea abies [L.] Karst.) forests greatly differing in their atmospheric N deposition and climatic conditions. As expected, both N concentrations and δ¹⁵N values in needles and roots were found to be significantly higher in the Solling stand (N-saturated) compared to the Hyytialä stand (N-poor). For both stands a typical vertical gradient of the soil ¹⁵N-enrichment was observed. As expected, the soil of N-polluted site (Solling) was ¹⁵N-enriched significantly more than that of N-limited site (Hyytialä) and this is explained by the presence of marked NO₃^- leaching at the Solling site. Although the annual trends (1990-1994) of N concentration in the foliage of spruce trees remained almost constant, their δ¹⁵N values significantly decreased with the increasing years of sampling. The ¹⁵N-depletion in spruce needle litter from 1990 to 1995 was by 2.0‰. This is explained by a slight decrease in N deposition at Solling site during this period.

The priority of this study was to investigate how selenium influences toxicity of Cd, Zn, Cu and Pb when the metals appear in the hydroponic solution in pairs. As a model subject mustard seedlings (Sinapis alba L.) were used. Except phytotoxicity of individual metals and Se-metal combinations determined through photosynthetic pigments content (chlorophyll a, b, total carotenoids) also metal accumulation in the roots and shoots was determined by the AAS method. Se in all metal combinations reduced the unfavourable effect of other metals tested for chlorophylls content, however, for carotenoids primarily the opposite effect occurred. For metal accumulation in the roots and shoots it was confirmed that Se stimulated only Cd (about 24%) and slightly Cu (about 9%) accumulation in the roots, while in the shoots there was inhibited accumulation of all metals tested. The strongest inhibition was observed in Pb accumulation (84.9%). This fact indicates that Se generates some barriers for metal transfer from the roots to the underground plant parts. In contrast, Cu, Zn, Pb and Cd increased Se accumulation in the roots in the range of 4 (in combination with Cu) to 68% (in combination with Cd) and in the shoots in the range of 11 (in combination with Pb and Zn) to 44% (in combination with Cd). In the shoots only Cu inhibited Se accumulation (about 67%).