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Hop purchasers impose still higher requirements on the quality of the final product, which is why hop granules have to be divested of all possible impurities. One of the places that are most at risk from the given point of view is the making of hop strings and the way they are attached to the hop-field supporting structure. Commonly used hop string attachments very often remain on the supporting structure after the harvest, spontaneously loosen in the following years, penetrate into the post-harvest processing stage of the technological procedure and negatively influence the output quality of the hops. The article summarizes the results of field experiments done during the pull-down of hop vines using a common hop string, but with various attachments with the aim of looking for the most suitable treatment which would exclude the risk of impurities penetrating from this stage of the technological procedure into the final product. The measurement carried out shows that so far the most advantageous treatment is hop string with simple attachment formed by twine 12 500. Breakage of hop strings occurred in 93% in twine, while with the rest of the vines only in wire.

The adverse effect of the application of phosphorus (P) on arsenic (As) adsorption by soils can result in increasing mobility and availability of As. However, in different soils, P might influence As adsorption differently. In this study, the arsenate [As^(V)] adsorption capacities of six soils with different properties and the effects of P application were studied. The results indicated that the adsorbed As^(V) contents all increased as a function of the As^(V) content in equilibrium. When analysed using the Langmuir and Freundlich equations, the maximum As^(V) adsorption capacity of 0.72 mg/g was found for an Alumi-Plinthic Acrisol, while the minimum capacity of 0.09 mg/g was observed for an Epigleyic Cambisol. The adverse effects of P application on As^(V) adsorption by the six soils were observed to be variable. When the P/As molar ratio in a culture experiment was increased from 0 to 10, the maximal and minimal decreases in the As^(V) adsorption capacity of 0.086 and 0.014 mg/g were found in the Alumi-Plinthic Acrisol and Epigleyic Cambisol, respectively. P was relatively more effective in competing for adsorption sites with As^(V) in the Alumi-Plinthic Acrisol and Luvi-Endogleyic Phaeozem due to their higher A/P values (decrease in adsorbedAs/added P) of 1.143 and 1.135, respectively. These results will help decrease the environmental risk of some As-contaminated agricultural soils through the controlled application of P.

Little information is available on how fertilizer application affects concentration of many elements in peeled potato (Solanum tuberosum) tubers and peels. We analyzed how long-term application of cattle slurry and mineral N, P and K fertilizers affects the yield of tubers, their dry matter content and concentrations of elements. In 2009, potatoes tubers were collected in control, cattle slurry (CS), mineral N₄P₂K₂ and combined CSN₄P₂K₂ treatment of the Ruzyně Fertilizer and Crop Rotation Experiment established on Illimerized Luvisol in Prague (Czech Republic) in 1955. Amount of N, P and K supplied by CS was 138, 30 and 172 kg/ha and the amount supplied by N₄P₂K₂ was 110, 31 and 186 kg/ha. Yield of fresh potatoes ranged from 20.6 in the control up to 31.2 t/ha in CSN₄P₂K₂ treatment. Dry matter content of unpeeled tubers, peeled tubers and potato peels was not significantly affected by fertilizer treatments probably because of not excessive N application. Normal cropping practices with application of CS and mineral N, P and K fertilizers did not significantly increase concentrations of trace elements in peeled tubers or potato peels on neutral soil with low trace elements availability. Concentrations of many elements (N, P, K, Ca, Mg, Cd, Cr, Cu, Mn, Ni, and Zn) were higher in potato peels than in peeled tubers, but the differences in the case of trace elements were relatively small.

Rumex obtusifolius is a troublesome weed widely spread in temperate grasslands and can be potentially used for detection of soils contaminated by trace elements. We asked how emergence and survival of its seedlings are affected by application of quick lime (Ca) and superphosphate (P) additives in soils contaminated by trace elements. We performed the pot seeding experiment with slightly acid Litavka soil contaminated by arsenic (As), cadmium (Cd), lead (Pb), and zinc (Zn) and alkaline Malín soil contaminated by As, Cd, and Zn. We used a control without any additives, Ca and P treatments in both soils. Higher and quicker emergence, together with substantially higher mortality of seedlings, was recorded in Litavka than in Malín. A positive effect of the Ca treatment on seedlings was recorded in Litavka, but a negative in Malín. Small seedlings with narrow and long leaves of reddish colour were recorded in Litavka in the control and in the P treatment both with high availability of Zn, Cd, and Pb. In the Ca treatment, leaves of seedlings were more elliptic and less reddish. In Malín, seedlings were green and substantially more vital in the control and in the P treatment than in Litavka. In the Ca treatment, small and unviable seedlings were recorded. Seedlings of R. obtusifolius are sensitive on high availability of Ca, Zn, Cd, and Pb in the soil.

This study was undertaken in order to test whether the development of nodule density over the vegetation period is different in lucerne stands grown for 1, 2 or 3 years continuously. For rapidly assessing nodule density in the field, a modified profile wall method was applied. Nodules were counted on a vertical profile wall, after spraying away a 2 cm layer of soil. For validating this method nodule density was determined on roots washed from monolith samples. Field data indicate that there is a shift of nodulation towards deeper soil layers with increasing maturity of lucerne stands. In 1-year lucerne nodulation was limited virtually to the top 15 cm of soil. In the 15-30 cm soil layer and in the subsoil (30-80 cm), nodule density increased with the cropping duration (1 year < 2 years < 3 years). Temporal decreases in nodule density during the vegetation period associated with dry spells were more pronounced for 2-years as compared with 3-years lucerne.

The influences of arbuscular mycorrhizal (AM) fungus on growth, gas exchange, chlorophyll concentration, chlorophyll fluorescence and water status of maize (Zea mays L.) plants were studied in pot culture under well-watered and drought stress conditions. The maize plants were grown in a sand and black soil mixture for 4 weeks, and then exposed to drought stress for 4 weeks. Drought stress significantly decreased AM colonization and total dry weight. AM symbioses notably enhanced net photosynthetic rate and transpiration rate, but decreased intercellular CO₂ concentration of maize plants regardless of water treatments. Mycorrhizal plants had higher stomatal conductance than non-mycorrhizal plants under drought stress. The concentrations of chlorophyll were higher in mycorrhizal than non-mycorrhizal plants under drought stress. AM colonization significantly increased maximal fluorescence, maximum quantum efficiency of PSII photochemistry and potential photochemical efficiency, but decreased primary fluorescence under well-watered and droughted conditions. Mycorrhizal maize plants had higher relative water content and water use efficiency under drought stress compared with non-mycorrhizal plants. The results indicated that AM symbiosis alleviates the toxic effect of drought stress via improving photosynthesis and water status of maize plants.

Our objective was to determine which rhizome extract from Japanese knotweed, Giant knotweed or Bohemian knotweed has the most significant inhibition effect on the germinated seeds. The seeds of white mustard were incubated with the extracts for two days under laboratory conditions. We monitored differences in number of germinated seeds, length of radicles, hypocotyls and root/shoot ratio between the control and experimental seeds. Inhibitory effect of extracts from dried knotweed rhizomes was confirmed, but without differences among tested plants. A higher allelopathic effect was revealed in the case of extract from aboveground parts.

In order to investigate the effects of soluble chitosan on plantlets growth in vitro and increase of minituber yield in potato micropropagation, plantlets of Agria cultivar were treated in vitrowith soluble chitosan at different concentrations including 0, 5, 15, 50, 150, 500, 750 and 1000 mg/l added to the MS tissue culture medium. Plantlets were subsequently transferred to the greenhouse and minituber yield parameters were evaluated. At the concentrations of 750 and 1000 mg/l of chitosan the culture medium failed to solidify. Application of 500 mg/l of soluble chitosan increased the shoot fresh weight, but its lower concentrations did not significantly affect this trait (P < 0.05). The 5 and 15 mg/l of soluble chitosan led to a significant increase in root fresh and dry weight of in vitro plantlets, whereas, higher concentrations, especially 500 mg/l, significantly decreased root fresh weight of in vitro plantlets. Application of 500 mg/l chitosan in vitro resulted in improved acclimatization of plantlets in the greenhouse as expressed by significant (P < 0.05) increase in minituber number and yield, compared to the control. The tested lower concentrations had no effect on yield parameters. The present results indicate that soluble chitosan can be successfully incorporated into potato seed production from in vitro plantlets.

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).

Biodegradation of triazole fungicide propiconazole was carried out in vitro by selected Pseudomonas strains isolated from tea rhizosphere. A total number of twelve strains were isolated and further screened based on their tolerance level to propiconazole. Four best strains were selected and further tested for their nutritional requirements. Among the different carbon sources tested glucose exhibited the highest growth promoting capacity and among nitrogen sources ammonium nitrate supported the growth to the maximum. The four selected Pseudomonas strains exhibited a range of degradation capabilities. Mineral salts medium (MSM) amended with glucose provided better environment for degradation with the highest degradation potential in strain MPR 4 followed by MPR 12 (72.8% and 67.8%, respectively).

The research project was carried out as a field experiment with application of the following crop rotation system: industrial potato, spring barley for fodder, winter rape and winter wheat, established in the random distribution of blocks in triplicate on gleyic luvisol formed of silty light loam. The aim of the research was to determine the influence of diversified organic fertilization based on composted wastewater sediments and farm manure on the community of soil fungi as compared to fields without fertilization and with NPK fertilization only. The fungi were cultured on the Martin medium and were counted and identified afterwards. As a result of three-year field experiments it was established that organic fertilization had a more determining effect on qualitative composition than numbers of soil fungi. Total number of fungal colony-forming units in the soil fertilized with Biohum at 10 t/ha and 5 t/ha was significantly higher than in soil with mineral NPK fertilization and without fertilization. Most frequently pathogens populated the soil in fields without fertilization and to a lesser extent the soil with mineral NPK fertilization. A positive influence of organic fertilizers on the fungal community structure was recorded. The number of pathogens was limited (to 1.2% in fields fertilized with farm manure) while the population of saprotrophic fungi possessing antagonistic properties increased.

Until recently, investigators had no idea how accurately cultivated microorganisms represented the overall microbial diversity. The cultivation-dependent approach is limited by the fact that the overwhelming majority of microorganisms present in soil cannot be cultivated under laboratory conditions. The development of molecular phylogenetics has recently enabled characterization of naturally occurring microbial biota without cultivation. There is a vast amount of information held within the genomes of cultivable and non-cultivable microorganisms, and new methods based on analysis of DNA allow to investigate this potential. In this work we show some aspects, advantages and disadvantages of classical and new approaches in taxonomical and functional description of bacteria present in natural microbial assemblages on the example of cultivable bacteria isolated from rhizosphere of plants, tobacco and black nightshade, planted in PCB contaminated soil. Biochemical analysis of isolates showed 8 different bacterial species. This identification was compared by discrimination using MALDI-TOF mass spectrometry and identity evaluation after sequencing of 16S rDNA. Six strains from original number of 8 were positively identified after 16S rDNA sequencing and their phylogenetic relations were compared. These analyses confirmed closed relations of all species (two of isolates exhibited the same characteristics and were discriminated as the same species Pseudomonas stutzeri) and also of Burkholderia xenovorans LB 400, a well-known PCB degrader. Nevertheless, only two isolates gave a positive reaction after amplification of the biphenyl dioxygenase gene and exhibited potential to degrade PCB. These results indicate that only a subset of the recovered molecular information, derived from active population based on molecular and functional analysis is relevant to microbial ecology.

Morinda citrifolia Linn. (family Rubiaceae) is a small tree occurring in tropical areas of the world. The plant contains several medicinally active components that exhibit the therapeutic effects such as antibacterial, antiviral and anticancer activities. Anti-genotoxic effects of aqueous extracts prepared using dried leaves of M. citrifolia was studied. Allium cepa root tip meristem cells treated with 7% hydrogen peroxide were used for eliciting anti-genotoxicity. For this purpose experiments were performed with A. cepa onion bulbs treated for 24 h with different concentrations (15 or 30 g/L) of aqueous extract with or without pre-treatment (1 h) with 7% hydrogen peroxide. A significant reduction in mitotic index was recorded in treatment groups over negative control. Chromosomal aberrations such as breaks, bridges, stickiness and polar deviations were observed in positive control and treatment groups. The highest (21.48) percentage of chromosomal aberrations was noticed in positive control. A significant reduction in chromosomal aberrations (9.39) was recorded in root tips treated with hydrogen peroxide followed by 15 g/L extract. H₂O₂ induced chromosomal aberrations were reduced due to leaf extract treatment indicates anti-mutagenic potential of the M. citrifolia. The observations suggest that M. citrifolia aqueous leaf extracts have anti-mitotic and anti-genotoxic effects; consequently oxidative stress induced aberrations due to H₂O₂ are efficiently restored in the extract treated A. cepa root meristem cells.

We have tested the effect of water, methanol and dichloromethane extracts from the leaves of several species of Impatiens (I. noli-tangere, I. parviflora, I. glandulifera) on germination of seeds Leucosinapis alba and Brassica napus. All of the tested extracts had inhibitory effects to seeds of all studied plants (except the dichloromethane extracts). The highest activity revealed methanol extract and extract from I. glandulifera.

Influence of growth regulators chlormequat chloride, ethephon, trinexapac-ethyl, and a combination of chlormequat chloride and ethephon on decreasing sunflower height was examined in the years 2006-2009. Height was reduced by as much as 63 cm by double application of chlormequat chloride (915 g/ha) + ethephon (465 g/ha) at early and later growth stage (BBCH 32 and 50). Trinexapac-ethyl (375 g/ha) did not affect the height. One-time application of chlormequat chloride (1440-2160 g/ha), chlormequat chloride (458 g/ha) + ethephon (233 g/ha) (BBCH 30 or 50), or ethephon (480 g/ha) (BBCH 30) was sufficient for a ca 30 cm reduction during flowering, but this effect did not last until harvest. With double application (BBCH 30 and 50), reduction lasted until harvest. For ethephon (480 g/ha), application at BBCH 50 reduced height by as much as 35 cm and lasted until harvest. Combining a lower rate of ethephon with ammonium sulfate was effectively equivalent to using a full rate. Flower head diameter at maturity showed no significant negative influence compared to the control. In 2008 and 2009, a delay in flowering onset was observed after applying growth regulators.

Little is known about the effects of air-drying and freezing on the transformation of phosphorus (P) fractions in soils. It is important that the way in which soils respond to such perturbations is better understood as there are implications for both P availability and loss to surface waters from soils. In this study, the effects of air-drying and freezing were investigated using two soils, one being a forest soil (FS) high in organic matter and the other being a sterile soil (SS) low in organic matter. Soil P was fractionated using a modified Hedley fractionation method to examine the changes of phosphorus fractions induced by air-drying and freezing. Generally, there were no significant differences of total phosphorus among the three treatments (CV% < 10%). Compared with field moist soils, freezing the soil evoked few changes on phosphorus fractions except that the resin-P increased in FS soil. On the contrary, air-drying significantly changed the distribution of phosphors fractions for both soils: increased the labile-P (especially resin-P) and organic-P (NaHCO₃-Po, NaOH-Po and Con.HCl-Po) at the expense of NaOH-Pi and occlude-P (Dil.HCl-P and Con.HCl-Pi). Resin-P significantly increased by 31% for SS soil and by 121% for FS soil upon air-drying. The effect of air-drying seemed to be more pronounced in the FS soil with high organic matter content. These results indicated that drying seem to drive the P transformation form occlude-P to labile-P and organic-P and accelerated the weathering of stable P pool. This potentially could be significant for soil P supply to plants and P losses from soils to surface waters under changing patterns of rainfall and temperature as predicted by some climate change scenarios.

The root system of six-year-old winter jujube (Zizyphus jujuba Mill. cv. Zhanhua) trees were manually pruned at 3, 5 or 7 times trunk diameter distance along both inter-row sides, to study the effects of root pruning on physico-chemical characteristics and biological properties of winter jujube rhizosphere soil. The results showed that the root pruning of 3 and 5 times trunk diameter distance increased the available nitrogen, phosphorus, potassium^[concentrations and pH values in the rhizosphere soil and decreased organic matter concentrations, the contents of amino acids, organic acids and total sugars in the root exudates, the populations of bacteria, actinomyces and fungi, and inhibited the activities of catalase, invertase and urease enzymes in contrast to the control in early stage when root pruning was applied. The determined indexes presented a reverse trend as those in early stage after new roots appeared. Compared to the control, the trees by root pruning had higher pesticides residues of the rhizosphere soil in the whole experiment. No differences were noticed between 7 times trunk diameter distance and the control. It is proposed that root pruning had greater impacts on physico-chemical characteristics and biological properties of the rhizosphere soil depending on root pruning intensity.

The aim of the experiment was to test the capacity of NO to reverse harmfull effects of nickel on bean (Phaseolus vulgaris L.) seedlings. Bean seedlings were grown on culture medium and treated with NO-donor - sodium nitroprusside (0.3 mmol/L) and Ni (0.2 mmol/L NiCl₂). After 4 days, the parameters of antioxidative response were determined in roots and leaves, as well as the concentrations of essential cations and Ni. In the presence of Ni alone, soluble protein, proline and superoxide-dismutase activity were increased, while peroxidase and especially catalase activities were supressed. Also, Ni induced a depletion of K, Ca, Mg, Mn and Zn, while the contents of Cu and Fe in the roots were increased. In the presence of NO, Ni-induced stimulation of superoxide-dismutase activity, soluble protein and proline accumulations was decreased, while the inhibition of peroxidase and catalase activities was eliminated. Calcium and Zn concentrations were increased by Ni in NO-treated seedlings, suggesting specific activation of the uptake of these elements as part of the protective processes regulated by NO. However, NO had no effect on the impact of Ni on K, Cu, Fe, and Mn concentrations. In conclusion, exogenous NO efficiently attenuates oxidative stress in bean, but does not prevent Ni-induced ion leakage.

Soil tillage practices involving various depth, intensity, and different methods of loosening the soil and treating plant residues have changed significantly in recent years and have spread also due to technical advance. The reasons are not only in expected benefits for crop production economics but also in preserving and increasing soil fertility. Although the practices were known for decades, their greatest development and use was seen only in the last 15 years, when decreasing production costs, efficient technology and effective herbicides were the main reasons for their development. At present, they are regarded as important alternatives to conventional management practices with moldboard plowing. Minimum soil tillage practices can contribute to effective soil management, however, risks associated with using these practices in various farming conditions shall be regarded. For cereals, these risks also include disease severity that is conditioned by several circumstances, which change along with the crop management practice, variety assortment or weather in individual years. Diseases that can be of greater importance in relation to the conservation soil tillage practice are stem-base diseases, root diseases and Fusarium head blight. Our experiments did not demonstrate an increased demand for protection against Fusarium head blight, foot diseases and take-all in the given system (three-crop rotation where wheat followed white mustard). Individual years were an important factor.

This study investigated copper (Cu) and lead (Pb) enrichment factor (EF) and mobility factor (MF) as possible indicators of their uptake by spinach (Spinaceae oleraceae) and carrots (Daucus carota) grown on a sludge-amended luvisol (SAL). Sewage sludge was applied to luvisol at different rates and spinach and carrots planted. Enrichment of Cu and Pb in SAL was determined, and values regressed with those of Cu and Pb concentrations in spinach and carrots. Concentration of Cu and Pb in vegetables was calculated using the regression model obtained, and calculated values compared with actual values. Pb MF were higher than Cu MF but Cu and Pb EFsoil values were < 3.0, indicating minor enrichment from sludge addition. EF had 10% reliability in predicting Cu and Pb uptake in vegetables. MF was more than 70% reliable in predicting carrot Cu uptake and spinach Pb uptake. EF and MF are not effective as predictors of heavy metal uptake by vegetables. The role of other soil components including root exudates and by-products from microbial activities should also be investigated.

In five consecutive growth seasons from 2003 to 2007 a response of maize variety Eurostar (var. FAO 240) to supply of NPK fertilizer supplemented with magnesium or zinc was investigated. The aim of the study was to evaluate the role of zinc (NPK + Zn) or magnesium (NPK + Mg) in controlling nitrogen management by maize crop fertilized with 80 and 140 kg N/ha. In the course of the study, total grain nitrogen content did not show any response to both experimental factors and weather variability, as well. However, the obtained results indicate, that magnesium and zinc have significantly increased SPAD (chlorophyll index) indices of maize cob leaf at anthesis. A significant effect of both factors interaction on nitrogen accumulation in grain and cob covering leaves was noted, but limited to the 80 kg N/ha treatment. The physiological role of Mg and Zn in nitrogen management was most manifested throughout its greater recovery from nitrogen fertilizer applied at the rate 80 kg N/ha, amounting to 92 and 94% respectively; for the NPK, it was only 78%.

The experiment was carried out to observe the influence of the CULTAN method (controlled uptake long term ammonium nutrition) on grain yield and yield formation of spring barley cultivar Jersey. In four-year small-plot experiment under conditions of the Czech Republic, two methods of nitrogen fertilization were used: conventional surface fertilization and local fertilizer injection rich in ammonium into soil during vegetation at BBCH 29-30 stages. Furthermore, the impact of sulphur amendment in fertilizer and increased dose of fertilizer were observed. Basic dose of nitrogen was 80 kg N/ha, increased dose 130 kg N/ha. At CULTAN treatment, same or significantly higher grain yields were obtained compared to conventional nitrogen fertilization. Grain yield at CULTAN fertilization is formed mainly on the main stem because of reduced tillering; it has the impact on significantly higher percentage of grain retained on 2.5 mm sieve. A tendency to lower protein content in grain was recorded at local injection of fertilizer compared to conventional fertilization. CULTAN-treated plants showed a lesser dependency of qualitative parameters on fertilizer dose and sulphur amendment in fertilizer. A positive influence of the CULTAN method on yield and quality of grain was observed mainly at the less fertile site.

Overgrazing affects typical steppe community in ways similar to grasslands in other areas. Exclusion of livestock grazing is one of the main management practices used to protect grasslands. However, it is not known if long-term exclusion of livestock grazing has positive effect on above- and belowground community properties in typical steppe of the Loess Plateau. We studied the long-term (20-year) cumulative effects of exclusion of livestock grazing on above- and belowground community properties compared with that before exclusion of livestock grazing in a typical steppe of the Loess Plateau, NW China. Our results show that twenty-year exclusion of livestock grazing significantly increased above- and belowground biomass, species richness, cover and height for five different communities. Most of belowground biomass was in the 0-20 cm horizon and grazing exclusion increased biomass especially at the depth of 0-10 cm. Our study suggests that long-term exclusion of livestock grazing can greatly improve community properties of typical steppe in the Loess Plateau.

In arid and semiarid regions of northern China, there is an increasing interest in using water-saving superabsorbent polymer (SAP) for field crop production. Experiments were conducted during 2009 and 2010 to study the growth and yield characteristics of summer corn (Zea mays L.) under different (control, 0; low, 10; medium, 20; high, 30 and very high, 40 kg/ha) rates of SAP in a drought-affected field of northern China. Corn yield increased slightly following SAP application at low and medium rate, but significantly at high and very high rates by 22.4 and 27.8%. At the same time, plant height, stem diameter, leaf area, biomass accumulation, harvest index and relative water content as well as protein, sugar and starch contents in the grain increased significantly following SAP treatments. The optimum application of superabsorbent polymer for corn cultivation in the study area would be 30 kg/ha as it best increased the grain yield and quality and maintained higher levels of soil nutrients. Lower rates (10 and20 kg/ha) or higher (≥ 40 kg/ha) rates would neither be sufficient nor economical. We suggest that the application of SAP at 30 kg/ha could be an efficient and economic soil management practice for summer corn production in the drought affected regions of northern China or other areas with similar ecologies.

Members of Brassicaceae have been frequently cited as allelopathic crop. The toxic effect of Brassica spp. may be caused by hydrolysis products of glucosinolates that occur in substantial amounts in the vegetative parts of Brassica spp. This study investigated the allelopathic potential of Brassica napus, B. rapa and B. juncea on the sunflower seed germination and seedling growth. Aqueous extracts of three species from two stages (full flowering and straw) of sampling were separately made with 0 (distilled water), 10, 20, 30 and 40% concentrations. This experiment was conducted in 2 × 3 × 5 factorial arrangement based on completely randomized design with five replications. There was a highly significant difference among different concentrations of extracts and also between two stages of extraction. All aqueous extracts significantly affected sunflower germination, germination rate, seedling root and hypocotyl length, fresh and dry matter weight when compared with distilled water control. The greatest concentration showed a stronger inhibitory effect. Root length was more sensitive to extracts than hypocotyl length.

The paper compares the quality of Festulolium, Dactylis glomerata and Arrhenatherum elatius at the end of the growing season over three years with the contrasting weather in the Czech Republic. The effect of pre-utilisation dates in June or July on the quality of grass forage in October, November and December (harvest dates) was investigated. In the first two years, Arrhenatherum elatius exhibited higher yields (P < 0.05) than Festulolium and Dactylis glomerata. In all treatments, differences between the species and between the years were inconsistent for organic matter digestibility (OMD) and neutral detergent fibre (NDF) but Festulolium showed the lowest crude protein (CP) in all years and crude fibre (CF) in the first 2 years. The longer re-growth time due to earlier final cut in summer increased the yield and decreased the nutritive value in winter. Yields of DM, OMD and CP content generally declined and the CF content increased with the delay of winter harvest. Significant species harvest date interactions in some years were due to the steep increase of CF and NDF in Festulolium. Based on DM yields and nutritive value, all species have some merits as forage for use in possibly extended grazing season. Festulolium and Dactylis glomerata could be used to extend the grazing period in continental conditions. Arrhenatherum elatius had sufficient quality at both dry and warm end of the growing season due to the fact that Arrhenatherum elatius was a representative of drought-resistant species; however, intense grazing could suppress it.

In this work, the effects of double, triple and quadruple combinations of gibberellic acid, kinetin, 24-epibrassinolide and polyamines (cadaverine, putrescine, spermidine, spermine) on the stomata movements in the leaves of barley seedlings grown under saline conditions were studied. In the control seedlings, the stomata number, stomata index and stomata length increased in the upper surfaces of leaves in comparison with their lower surfaces. In addition, the epidermis cell number in the leaves of control plants were fewer in the upper surface than that in the lower surface, but the stomata were statistically in the equal width in both surfaces. As for the applyings, they generally decreased stomata number, stomata index, stomata length and epidermis cell number, while they increased the stomata width in the upper and especially in the lower surface according to the control. The growth regulators used may have served to adaptation of barley seedlings to saline conditions by causing a decrease in most of the mentioned parameters.

Soil compaction heterogeneity and water content are supposed to be decisive factors influencing plant growth. Our experiment focused on simulation of two soil moisture levels (0.16 and 0.19 g/g) plus two levels of clod proportion (30 and 60% volume) and their effects on root and leaf variables of maize (Zea mays L.). We studied number of primary and lateral roots as well as primary root length at the particular soil depths. Statistical tests showed that the decrease rate of the number of roots versus depth was significantly affected by the two studied factors (P < 0.01). Soil moisture and clod occurrence, interactively, affected leaf biomass (P = 0.02). Presence of clods modified root morphological features. Particularly, the diameter of primary roots in the clods was significantly higher than of those grown in fine soil (P < 0.01). For primary roots, which penetrated clods, branching density decreased considerably for the root segments located just after the clods (P = 0.01). Regarding their avoidance to clods and tortuosity, large differences were found between primary roots grown in the contrasting soil environments.

The accumulation of heavy metals in the tissues of earthworms is a helpful indicator of environmental contamination. The degree of substrate contamination can be additionally evaluated on the basis of survivability, reproduction and body mass of earthworms. In this study Eisenia fetida Sav. earthworms were exposed to a series of increasing concentrations of cadmium and mercury. The numbers of animals and their body mass were checked after 4 and 8 months. The strongest impact of substrate contamination was exerted upon the number of young individuals and cocoons. The cadmium contamination did not affect adversely the mass of earthworms, whereas in the mercurycontaminated group the decline in body mass was evident. After 8 months of experiments, the content of heavy metal in the bodies of earthworms was determined. An evident relationship between the cadmium and mercury contents in the substrate and their accumulation in earthworms' tissues was found. The concentration in the bodies exceeded the level in the substrate.

The effect of mineral and organic fertilization on grain yield and quality of winter wheat in crop rotations and in continuous cropping was investigated. The study was conducted in Borovce (near Piešťany) on Luvi-Haplic Chernozem in the years 2002-2004. Mineral and organic fertilization of winter wheat growing in monoculture was more effective than mineral fertilization in crop rotations. In the case of winter wheat growing in monoculture, statistically higher grain yield (5.10 t/ha) was obtained in the variant with straw and green manure incorporation compared to the control variant (4.73 t/ha) and the variant with straw incorporation (4.75 t/ha). In the Solara variety, statistically higher number of plants before harvest was recorded in the variant with straw and green manure incorporation (194 plants per 1 m²) than in the variant with straw incorporation only (149 plants per 1 m²). As for the winter wheat grain in the sequence 2, based on the wet gluten content (30.3%) the Solara variety was classified in the elite class E in the variant with straw and green manure incorporation, and in the improving class A in the control variant.