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An interrelationship between introduced and indigenous rhizobia focused on their competitiveness in nodulation was evaluated in a soil pot experiment. Clover seeds were inoculated by six different gradual concentrations of inoculum of two effective Rhizobium leguminosarum bv. trifolii isolates (inoculation strains 1/2 and 14/2). At the beginning of flowering, clover plants were removed from the pots, and nodules from each pot representing different degrees of inoculum level were taken for reisolate cultivation. The PCR technique was used for the identification of rhizobial reisolates, random amplified polymorphic DNA product patterns were acquired and analysed. Nodule occupation by inoculation strains or indigenous Rhizobium leguminosarum bv. trifolii strains was assessed by comparing the number of nodules formed by inoculation or indigenous strains and inoculation strains competitiveness was calculated. Nodule occupancy by the inoculation strain 1/2 increased sharply with the increase in inoculum dose, whereas in inoculation strain 14/2 more nodules were formed gradually starting from low inoculum level. Competitiveness of inoculation strain 1/2 was calculated as low and was documented by an absence of nodule occupancy in four inoculation levels. On the other hand, competitiveness of the inoculation strain 14/2 was considerably higher, and even in low inoculum dose this strain was more competitive than native rhizobia. Although both the inoculation strains 1/2 and 14/2 were found highly efficient in nitrogen fixation, only the strain 14/2 was able to manifest this characteristic due to the higher competitiveness when applied in lower doses.

Effect of sugar beet seed inoculation with a bacterium Pseudomonas fluorescens and treatment by fungicides Thiram 42-S and Dithane S-60 with and without seed inoculation aiming to control Aphanomyces cochlioides - root decay agent was studied. The trial lasted for three years on two soil types (Mollic Gleysols and Eutric Cambisols). The following parameters of sugar beet yield and quality were investigated: root yield, sugar content, sugar in molasses, sugar yield as well as percentage of the infected and decayed plants as a consequence of parasite fungus infestation. The highest average sugar beet root yield was obtained in the variant of the seed treated with fungicide Thiram 42-S and inoculated with bacterium P. fluorescens (85.15 t/ha). However, there were no statistically significant differences (P < 0.05) between the above-mentioned variant and the one with seed inoculated only with bacterium P. fluorescens (84.63 t/ha). The highest mean sugar content of 16.39% was also accomplished during the three-year investigation in the variant of the inoculated seed treated by fungicide Thiram 42-S. All other variants accomplished statistically very significantly lower values of this parameter. The same variant was characterized by the highest mean sugar yield value (12.79 t/ha) on both soil types. Namely, an average sugar yield of the variants inoculated with bacteria was 11.22 t/ha and by 44.22% higher compared to an average yield of non-inoculated variants. The highest percent of the infected and decayed plants (average value on both soil types in the three year investigation) was reported in the control variant (28.92% infected and 25.00% decayed plants) whereas the lowest one was detected in the variant of the seed inoculated with bacterium P. fluorescens in combination with low dose of fungicide Thiram 42-S (4.70% infected plants and 2.88% decayed plants). An average percent of the infected plants inoculated with bacterium P. fluorescens was 9.13% whereas the aforesaid value of the plants infected with parasitic fungus A. cochlioides in non-inoculated variants was by 146.00% higher being 22.42%.

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%).

The effect of three different growing methods, and plant age on the yield of purple coneflower (Echinacea purpurea L.) Moench., Asteraceae are described. The weight of fresh and dry mass of rhizomes increased significantly with the age of the plants. Independently of the age, the highest yield of rhizomes (1779 g/m² FW - 589 g/m² DW in the third year) was found in the plants grown from root cuttings and the smallest (385 g/m² FW - 108 g/m² DW in the third year) from seeds sown directly into the soil. A similar dependence was obtained in the yield of flower heads. No relation was noticed between the growing method and the flavonoids and polyphenol acids contents neither in the flower heads nor in the rhizomes. The polyphenol acids content was slightly higher in the flower heads (2.85% in the third year) than in the rhizomes (2.22% in the third year). The results demonstrate that the experimental factors can stimulate increased yield of rhizomes and flower heads of E. purpurea.

This study was carried out to investigate the effect of treated wastewater on soil chemical and physical properties. Field experiment was conducted in Borkhar region in Isfahan province in central Iran with two water treatments of wastewater and groundwater under sprinkler and surface irrigation systems for three crops of sugar beet, corn and sunflower. Soil samples were collected to 120 cm depth to determine concentration of lead (Pb), manganese (Mn), iron (Fe), cadmium (Cd), nickel (Ni), cobalt (Co), copper (Cu) and zinc (Zn). Irrigation systems had no significant effect on extractable heavy metals in soil. The accumulation of Pb, Mn, Ni and Co in the soil increased significantly in the wastewater treatment as compared to the groundwater treatment. The accumulation of Pb, Mn, Ni, Co, Cu and Zn decreases with the soil depth. Treated wastewater showed no effect on the increase of Fe, Cd, Ni, Cu and Zn during growing season. The irrigation system had a significant effect on infiltration rate, bulk density and total porosity. Under sprinkler irrigation system the infiltration rate increased significantly

The effect of osmotic stress on oxidative injury, compatible solutes content and water relations was investigated in two maize cultivars (Zea mays L. cv. Ankora - drought-sensitive and cv. Nova - drought-tolerant). Relative water content in leaves of both cultivars decreased after drought treatment, leaf water loss of sensitive cv. Ankora was higher than that of cv. Nova. The 24 h water stress induced by 0.3M sorbitol (-1.4 MPa) resulted in a damage of cell membranes. Lipid peroxidation rose in all studied organs of cv. Ankora and electrolyte leakage in roots of cv. Ankora was much higher than in cv. Nova. Similarly, proline content increased significantly in all studied organs of cv. Ankora. Content of soluble sugars increased in all studied organs of both cultivars, but the mesocotyl of cv. Nova accumulated the highest amount of sugars. The electrolyte leakage was the highest in the roots of both cultivars. Osmotic stress had deep influence predominantly on the roots of both cultivars. It is apparent that stress impact on the drought-sensitive cv. Ankora was deeper than on the drought-tolerant cv. Nova.

In 1999-2001 sulfur and sulfate concentrations were studied in expanded young leaves of rapes of the line variety Lirajet and hybrid variety Pronto at the onset of stem elongation (DC 30), flowering (DC 64) and early maturity (DC 70) in different localities of the Czech Republic. Except the S-deficient site the concentration of total sulfur and sulfates in leaves considerably increased in higher growth stages. A less steep increase in S concentration in leaves was associated with rather humid growing season, especially with April precipitation. Great time variations in sulfur concentrations in leaves signal a possibility of diagnostic misinterpretation of plant analysis without exact definition of growth stage. The shape of trend of variations in S concentration in leaves indicates the S nutritive state of the site and the intensity of upward transport of sulfates with soil moisture in the crop nutrition with sulfur. Good yields of rapeseed were connected with minimum concentration of total sulfur 0.5%, and sulfate sulfur 0.2% in leaf dry matter at DC 30. The proportion of sulfates in total concentration of sulfur in rape leaves ranged from 30 to 60% at the onset of stem extension and it increased in higher phenophases. At flowering, sulfates accounted for 80% and more at sites where sulfate uptake from the soil environment was not problematic. Besides the S-soil test, the results of investigations indicate the importance of CEC value of soil for the preventive diagnosis of S-nutrient state of the site.

Seven cultivars of common buckwheat were tested in field trials under two levels of nitrogen fertilisation on two experimental sites during 1998-2000. The aim of the experiments was to evaluate the influence of cultivar, nutrition and year on main technological quality parameters (thousand achenes weight, volume weight, proportion of fractions on sieves 4.5 and 4 mm, proportion of husks and yield of groats). The differences were observed between buckwheat cultivars in all observed parameters of technological value. Nitrogen fertilisation before sowing (50 kg.ha^-1) did not influence any parameter. On the contrary, buckwheat technological value was influenced by sequence weather (particularly rainfalls) during flowering and achenes formation periods (July). The influence of year was manifested especially on development of endosperm and husks of achenes. Better growing conditions on experimental site Uhříněves caused lower values of volume weight, lower proportion of pericarp (husks) and considerably higher proportion of fraction over 4.5 mm.

Water infiltration into the soil profile and runoff losses in arable lands are related to the condition of the top layer. The tillage treatment (included no-till) of the top layer plays a key role in changes of the hydro-physical properties, mainly saturated hydraulic conductivity (K) of the treated layer. This paper is focused on the influence of repeated tillage treatments in the same locality on K in a relatively homogeneous soil profile. The field experimental work was conducted in 1997 and repeated in 2000 after three years of repeated treatments in an experimental field of the Research Institute of Plant Production, Prague on Hapludalfs (US Classification)/Orthic luvisol (FAO). The whole experimental site was divided into four tillage treatment areas (TTA) that were maintained using different tillage treatments. A pressure ring infiltrometer (Matula and Kozáková 1997), mounted on the top of a single iron infiltration ring was used to run infiltration tests. The infiltration during the steady state flow (for a long time) was measured, evaluated and K values were calculated. Matula (2002) summarised the theoretical background for the pressure ring infiltrometer and described the final equations for evaluation of the infiltration test results. The conventional ploughing did not give any significant changes in K values after three years. Reduced till treatment and no-till treatment show a significant decrease in the infiltration rate v(t) after three years. The K value decreased approximately three times for reduced till and six times for no-till treatment. The decrease on this type of soil can cause several negative results from the aspect of surface soil hydrology and agriculture (surface runoff increase, water storage decrease, yield decrease, increase in soil compaction of surface layer, soil erosion increase).

The influence of accelerated ageing test (AAT), i.e. of higher temperature and humidity, on the content and composition of phenolic compounds in the grains of five cultivars of wheat (Triticum aestivum L.) was studied in the years 1998 and 1999. Total polyphenols were determined spectrophotometrically by Folin-Ciocalteau's phenolic reagent and free phenolic acids by an HPLC method in control samples and after deterioration treatment (AAT) in the Ebi, Estica, Nela, Samanta and Šárka cultivars. Statistical significance of deterioration treatment, cultivar, cultivation site, and harvest year was proved. Content of total polyphenols increased during deterioration and levels of the individual free phenolic acid changed depending on their structures. Mean contents of total polyphenols varied from 600 to 960 mg/kg of dry matter. The increase caused by the AAT ranged between 0-20%, the greatest mean increase was observed in the cultivar Nela (by 19%). Sinapic acid (as high as 540 mg/kg of dry matter), 3-hydroxy-benzoic acid and 7-hydroxycoumarin were determined as the major phenolic acids and coumarins. A decrease of free phenolic acids containing methoxy groups in their molecules (sinapic and vanillic acids) and an increase of phenolic acids with free hydroxy groups (caffeic and gallic acids) was observed after deterioration treatment. Statistically significant (P ≤ 0.05) effect of AAT on the content of free phenolic acids was observed.

The distribution of the size of wheat starch granules using the method LALLS (Low Angle Laser Light Scattering), followed by the evaluation of the effect of variety, experimental site and intensity of cultivation on the vol. % of the starch A (starch granules > 10 μm) was determined. The total starch content and crude protein content in dry matter of flour T530 in selected collection of five winter wheat varieties were determined. Vol. % of the starch A in evaluated collection of wheat varieties varied between 65.31 and 72.34%. The effect of a variety on the vol. % of starch A seemed to be more marked than the effect of site and intensity of cultivation. The highest vol. % of starch A reached evaluated varieties from the quality group C, i.e. varieties unsuitable for baking utilisation (except variety Contra with high total content of starch in dry matter of flour T530, but relatively low vol. % of starch A). A low vol. % of starch A was also found in the variety Hana (very good variety for baking utilisation). Certain variety differences followed from the evaluation of distribution of starch fractions of starch granules, forming starch A. In the case of varieties Hana, Contra and Siria higher representation of fractions up to 30 μm was recorded, while starch A in the varieties Estica andVersailleswas formed in higher degree by size fractions of starch granules over 30 μm and particularly size fraction > 50 μm was greatest in these varieties of all evaluated samples. With increasing total starch content in dry matter of flour T530 the crude protein content decreased; the vol. % of starch A not always increased proportionally with increasing total starch content.

Field experiments were carried out to study effects of zinc application on quality traits of barley in 1994-1996. The treatments were applied as 0 and 23 kg/ha of zinc sulphate and incorporated into soil before sowing. The experimental design was split plot with four replications. Barley genotypes responded differently to zinc application in relation to thousand grains weight, protein content and starch content. A significant increase was determined for thousand grain weight in cultivars Tokak 157/37 and Cumhuriyet 50, for protein content in Orza, Bülbül 89 and Anadolu 86, for starch content in Karatay 94 and Cumhuriyet 50, while a significant decrease has been found for thousand grain weight in Karatay 94 and Obruk 86 and for protein content in Karatay 94, Cumhuriyet 50 and Tarm 92. When feeding and malting quality are considered together, Karatay 94 and Cumhuriyet 50 are the most suitable cultivars for growing in zinc-applied soils of semi arid areas.

Analysis of spatial distribution and correlation of soil properties represents an important outset for precision agriculture. This paper presents an analysis of spatial distribution and mutual correlations, both classical and spatial, of soil properties in an agricultural field in Klučov. Clay and fine silt content, pH, organic carbon content (C_org), moisture (Q), total porosity (Pt), capillary porosity (P_c), and coefficients of aggregate vulnerability to fast wetting (K_v1), to slow wetting and drying (K_v2), and to mechanical impacts (K_v3) were determined. Semivariogram ranges from 206 m (clay content) to 1120 m (K_v3) were detected. Many relationships between soil properties were spatially based. Fine silt content and Corg proved to be the most important soil properties controlling all the three aggregate vulnerability coefficients, which was not clear for K_v2 from classical correlation only. Determined spatial correlations and similarities in spatial distribution may serve as groundwork in delineation of different zones for site-specific management.

A survey was made to evaluate sanitary status of grapevines in the Czech Republic with regard to occurrence of economically important viruses. Propagation material of 109 grapevine clones was tested for presence of Grapevine fanleaf virus, Arabis mosaic virus, Grapevine leafroll-associated virus 1, Grapevine leafroll-associated virus 3, Grapevine virus A, Grapevine virus B and Grapevine fleck virus. Dormant canes were collected and cortical scrappings were analyzed by DAS-ELISA. All seven viruses tested were found to be widely spread in Czech propagation material of grapevine. From 330 individual vines tested, 148 vines were found to be infected with at least one virus. From 109 clones tested, in 98 clones at least one vine negative for tested pathogens was found. Such vines were promoted as candidate plants into screenhouse in Faculty of Horticulture Lednice and will be further tested by other methods. Sanitation of infected grapevine clones is needed in near future.

N fertilization has a substantial influence on sunflower (Helianthus annuus L.) seed yield and quality. It was also well established that high-yielding sunflower hybrids had more N requirement than old cultivars such as open-pollinated ones. However, in Turkey, no sufficient information regarding the response of new developed oilseed sunflower hybrids to nitrogen fertilization under irrigated conditions. Therefore, a 2-year study was conducted to determine the effects of nitrogen application rates on the growth, yield, and yield components of two oilseed sunflower hybrids (AS-508 and Super 25) under irrigated conditions. In this study, all plant parameters were significantly influenced by applied nitrogen fertilizer rates. Yield response to nitrogen rates was positive and linear. Our research data indicated that under irrigated conditions N rate of 120 kg/ha was adequate for sunflower production in this region.

The present investigation was conducted to know the impact of bio-inoculants in low input field conditions on the magnitude and direction of gene effects and mean performance of some morphological and productivity traits in three wheat cultivars WH 147 (medium mineral input), WH 533 (drought tolerant), Raj 3077 (drought tolerant) and six generations namely P₁, P₂, F₁, F₂, BC₁ and BC₂ of three crosses i.e. WH 147 × WH 533, WH 533 × Raj 3077 and WH 147 × Raj 3077. The experiment was conducted in randomised block design with three replications and three treatments i.e. control (C, without inoculation), inoculation with arbuscular mycorrhiza fungi (AMF, Glomus fasciculatum), and AMF + Azotobacter chroococcum (Azc). Mineral fertilizer (80 kg N/ha + 40 kg P/ha + 18 kg ZnSO₄/ha) was applied in all the three treatments. The application of bio-inoculants, AMF and AMF + Azc had a positive effect on plant height, peduncle length, grain yield, biological yield and harvest index in various populations of all the crosses. However, in some of the generations the impact of bio-inoculants was insignificant. The joint scaling test revealed that additive-dominance gene effects were mainly operative in governing expression of peduncle length, tillers per plant, plant height, grains/spike, grain yield and all traits except days to flowering and harvest index in crosses WH 147 × WH 533 and WH 533 × Raj 3077. The application of bioinoculants influenced gene effects for days to flowering, days to maturity, flag leaf area, spike length, grains/spike, 1000 grain weight and harvest index where complex genetic interactions were changed to simple additive-dominance gene effects in the cross WH 147 × Raj 3077. Likewise, additive-dominance gene effects were altered and digenic interactions exhibited for days to maturity, flag leaf area in WH 147 × WH 533 and days to flowering, plant height, flag leaf area in WH 533 × Raj 3077. Flag leaf area and plant height were governed by additive gene effects while for days to maturity and 1000-grain weight both additive and dominance gene effect were important. Duplicate epistasis was important in all the three crosses for days to flowering and harvest index and in the cross WH 147 × Raj 3077 for grain weight grains per spike and flag leaf area.

High yielding varieties of rice (Oryza sativa) cultivars were tested for their tolerance to different levels of molybdenum (Mo) (0.1µM - control, 0.2, 0.4, 0.8 and 1.6µM) in nutrient solution at pH 6.8. Seeds of rice were germinated and grown in presence of molybdenum under controlled environmental conditions. Standard growth parameters such as root length, shoot length, root/shoot dry biomass and root/shoot tolerance index were tested as markers of molybdenum toxicity. Measurements as early as 48 hours after the germination did not yield consistent results. However, root measurement on 3^rd, 6^th and 9^th day after root emergence showed significant differences among cultivars of rice. Rice cultivars Annapurna, Kusuma, Deepa and Vaghari developed better root system while, Paridhan-1, Pusa-2-21 and Ratna showed poor growth of the roots in presence (0.8µM) of molybdenum. The root tolerance index (RTI) and the shoot tolerance index (STI) in Annapurna, Kusuma and Deepa in rice were high indicating their tolerance to molybdenum; Paridhan-1 and Ratna, however, showed low RTI and STI. Based on the growth parameters, twenty cultivars of rice were ranked in respect of their tolerance to molybdenum: Annapurrna > Deepa > Kusuma > Vaghari > Hamsa > Vikram > Bharati > Paridhan-2 > Aswathi > Subhadra > Sankar > Sakti > Nilgiri > Rudra > Hema > Pragati > Pusa-2-21 > Ratna > Paridhan-1, respectively. Molybdenum toxicity was correlated with increased peroxidase and catalase activity in different cultivars of rice. This method can be employed for quick screening of rice cultivars for molybdenum tolerance in breeding programmes.

As, Cd, Pb and Zn accumulation in the aboveground biomass of seven clones of Salix spp. and changes in element uptake by plants after element addition to soil were studied in a pot experiment. Unpolluted Chernozem (Suchdol) as a control and soils with addition of As (100 mg/kg), Cd (40 mg/kg) and either Pb (2000 mg/kg) (Suchdol-Pb) or Zn (2000 mg/kg) (Suchdol-Zn) were used for the experiment. Significant differences were found in the accumulation of elements between willow clones and also between different element additions to the soil. Although As and Cd uptake slightly increased in Suchdol-Zn soil compared to Suchdol-Pb soil, the element removal from soil was significantly higher in Suchdol-Pb soil due to a significant reduction of aboveground biomass yield in Suchdol-Zn soil caused by Zn phytotoxicity. The yield reduction decreased the uptake of plant-available elements by biomass, thus higher plant-available portions of As and Cd were found in Suchdol-Zn soil. Element removal from soil was more dependent on element contents in willow tissues in Suchdol-Pb soil than in Suchdol-Zn soil, where willow plants exhibited physiological symptoms of phytotoxicity.

The Cd and Zn accumulation and phytoextraction potential of seven willow clones was investigated in a pot experiment for two vegetation periods. Heavily polluted Fluvisol-Litavka, moderately contaminated Cambisol-Pribram, and unpolluted control Chernozem-Suchdol were used. Significant differences were found in Cd and Zn accumulation between the willow clones. Cd and Zn were transferred from roots to aboveground tissues and all tested clones confirmed higher Cd and Zn accumulation in leaves than in twigs. Cd and Zn amounts removed by willow leaves were the highest from the most polluted soil (up to 83% Cd and 71% Zn of total removal). Therefore the harvest of leaves is necessary if willows are planted for heavy metal phytoextraction. Although the extremely high Zn contamination of Fluvisol-Litavka significantly reduced biomass production, willows planted in this soil showed the highest Zn removal because of extremely high Zn accumulation (max. 5061 ppm in leaves). Clones planted in moderately contaminated soil achieved the highest Cd removal. Clones showed different abilities to remove Cd and Zn, which was dependent on soil type and contamination level. Remediation factors were determined less than 1% for Zn in the heavily polluted soil and also unsatisfactory for Cd. However, it was shown that willows were suitable phytoextractors of moderately contaminated soil. About 20% of Cd and 4% of Zn were removed by harvested biomass from the total content of soil after two vegetation periods.

Problems concerning total dry weight and distribution of underground phytomass were studied in a pasture trial at Rapotin near Šumperk, the CzechRepublicin the period 1995-1999. The total weight of dry underground pasture phytomass (DUP) was 976 g/m² (5-year average) in a soil layer of 0-200 mm (both live and dead roots). The DUP was significantly increased by mineral fertilizers (90 kg N/ha, 30 kg P/ha a 90 kg K/ha). The weight of DUP was not significantly influenced by a grazing system, renewal or resowing of the original grassland. In unfertilized plots, DUP weight amounted to 989 g/m², i.e. 92 g/m² (8.6%) less than in fertilized plots in the period 1996-1999. In the same period, under the grassland exploited by rotational grazing 1142 and under continuous grazing 1082 g/m² DUP were determined, i.e. by 60 g/m² (5.5%) less. The highest DUP weight in the period 1996-1999 was found in autumn 1997 (1222 g/m2) immediately before achieving the maximum forage yield in May 1998. In a layer of 0-20 mm, 54.6% of the total DUP was found. In this surface layer, significant increase in the DUP weight was found in fertilized plots. In 1999, some 88.5 and 90.2% of DUP were concentrated in unfertilized (903 g/m²) and fertilized (952 g/m²) plots, respectively in a layer of 0-100 mm.

The observations were conducted on chernozem soil in a sugar-beet production region in 1971-2002. Six variants of organic amendment were examined: l - straw harvest, 2 - straw harvest + green manuring, 3 - straw incorporation, 4 - straw incorporation + green manuring, 5 - straw burning, 6 - straw burning till 1977 + intercrop, incorporation of farmyard manure at 10 t/ha since 1978. The effect of organic amendment on winter wheat continuous cropping was statistically significant. On average of the whole period (32 years), the highest yields were produced in variants with straw burning (var. 5) - 6.04 t/ha and with green manuring (var. 2) - 6.03 t/ha, and lower yields in variants with straw incorporation into soil (var. 3) - 5.65 t/ha, (var. 4) - 5.67 t/ha. The smallest differences between variants were found in the first decade of the experiment. Over time (in the second and third decades), the differences increased and positive effects of green manuring and straw burning and adverse effects of straw incorporation into soil increased. The yield level of winter wheat continuous cropping was high under the given conditions. The yield for the whole period of the experiment averaged 5.85 t/ha, the yields 5.19, 6.54 and 5.76 t/ha were obtained in the first, second and third decade, respectively.

Four kinds of cereal crops were grown without farmyard manure application. The effect of farmyard manure was supposed to be replaced by post-harvest residues (PH treatment) or by ploughing the total by-product, i.e. straw (PZ treatment) into soil. After seven years of application, this soil farming system did not influence the contents of Cox and Nt in soil. The amount of organic carbon had declined after the first year, but in the following years it remained at the same level (1.2%). The total nitrogen content increased from 0.143 to 0.166% without any considerable difference between the treatments. The amount of microbial biomass (C_mic) in PH treatment had been varying and in 2000 it decreased approximately by a half (from 215.96 to 132.00 mg C/kg of soil dry matter). The input of organic matter due to ploughing the whole by-product (PZ treatment) into soil acted favourably and the value of C_mic in 2000 was quite comparable with the average values of the individual years of 1994-1997. This land management and cereal growing caused a reduction of the ratio of microbial biomass carbon to soil organic carbon (C_mic/C_org). In the year 2000, the values decreased from 2.59 to 1.09% and from 2.88 to 1.82% in PH and PZ treatments, respectively. The amount of the biologically releasable nitrogen (Nbiol) and the intensity of nitrification were the highest in the year 2000. There was a moderate negative correlation (r = -0.474) between the N_biol values and biomass amount values in PZ treatment, and a very close negative one (r = -0.972) in PH treatment. This relation became strong in both treatments when the values Cmic/Corg and Nbiol were compared, i.e. r_PH = -0.863 and r_PZ = -0.921. The results confirmed that the amount and the quality of organic matter influence microbial biomass and its activity which is responsible for the nutrient release.

Changes in N-NO3- content and N-NO3- increase after incubation were studied in 1992-1998 in soils of two farms situated in identical soil and climatic conditions (in spring and autumn seasons). The two farms produce sugar beet and grain crops, but since 1991 they have used different types of organic fertilizers. Farmyard manure has regularly been applied to root crops on Dobrá Voda farm; since Chvalina farm does not have animal production, green manure and plowing-in of beet tops and straw are used for organic fertilization. Soils with regular applications of farmyard manure show a trend of lower N-NO3- content than the soils of the farm without animal production. At Dobrá Voda N-NO3- content was about 12 ppm N in spring and 9 ppm N in the autumn season while the respective values for Chvalina were 14 and 10 ppm N. On the hand, N-NO3- increase after soil incubation (12-14 ppm N) was higher in Dobrá Voda soils than in soils from Chvalina farm (5-8 ppm N).

The Pb, Zn and Cd phytoextraction potential of 14 different plants was assessed in a chelate induced phytoextraction experiment. In the used soil heavy metals mainly reside in carbonate, organic matter, and residual soil fractions. The addition of a chelate, 5 mmol/kg ethylenediamine-tetracetic acid (EDTA), increased the proportion of phytoavailable Pb, Zn and Cd in the soil (dissolved in soil solution and exchangeable from soil colloids), and also their uptake by tested plants up to 48 times (Sinapis alba), 4.6 times (Raphanus sativus oleiformis), and 3.3 times (Amaranthus spp.), respectively, compared to the control. The biodegradable chelate ethylenediamine-disuccinic acid (EDDS) was generally less effective (tested on a selection of 4 plant species), except for Cannabis sativa. In a treatment with 10 mmol/kg EDDS, Pb, Zn and Cd concentrations of 1053 ± 125, 211 ± 16 and 5.4 ± 0.8 mg/kg, respectively, were measured in the biomass of Cannabis sativa and were 105, 2.3 and 31.7 times higher, respectively, than in the control treatment. The calculated Pb phytoextraction potential of Cannabis sativa amounted to 26.3 kg/ha.

Pea (Pisum sativum L.), sunflower (Helianthus annuus L.) and maize (Zea mays L.) plants were cultivated for 10 days in hydroponics at 1mM and 7mM nitrate or ammonium concentrations at regulated pH 6 and ambient CO2 level. Plant growth, content of total N and both ions in plant tissues, uptake of water and both N ions were evaluated, N uptake related to transpiration mass flow and to diffusion supply was calculated. Pea and sunflower preferred nitrate nutrition while maize plants used both N ions. The content of total N as well as of both N ions in plant tissues increased with N level with some exceptions. The uptake of both N ions related to transpiration mass flow was dependent on transpiration rate and N ion concentration. At a 1mM N concentration the uptake of N ions related to transpiration mass flow was low and reached in maize up to 16 times, in sunflower 11 times and in pea 2-3 times lower values in comparison with diffusion supply. At a 7mM N concentration N uptake in pea plants was totally supplied by transpiration mass flow, in sunflower plants the ratio of N supply related to transpiration mass flow amounted to 50% and in maize plants N supply through diffusion prevailed, amounting to 70-80%. These results explicate N starvation at low N supply that can intensify at elevated CO2 causing decreased stomatal diffusion.

A morphometric study of Amaranthus cruentus, A. retroflexus and their hybrid, A. × turicensis based on 75 plant samples (750 inflorescences), collected throughout the Olomouc-Holice area (Czech Republic), is presented. Using multivariete methods (including cluster analysis and canonical discriminant analysis), the existence of three groupings of plants was proven. The hybrid exhibited intermediate values of the width and length of female tepals, length of awl-shaped bracts, and seed size when compared with parental species. A germination experiment showed that dark seeds of A. × turicensis as well as dark seeds of A. retroflexus germinate scarcely and independently on the day length while light seeds of A. cruentus germinate promptly and markedly better under a short day regime. The chromosome analysis showed that A. retroflexus, A. cruentus, and A. × turicensis have the same chromosome number 34.

Zinc distribution in the main soil fractions and zinc accumulation in potatoes, maize, wheat and barley after different soil treatments (basic sludge rate, triple sludge rate, NPK, NPK + inorganic Zn) were investigated in a field experiment conducted at five localities of the Czech Republic (Červený Újezd, Hněvčeves, Humpolec, Lukavec, Suchdol) with different soil and climatic conditions. Three soil types were investigated in the experiment: clay-loamy Chernozems, loamy Luvisols, clay-loamy Luvisols and two loamy Cambisols. Sequential analyses provided an overview of soil Zn distribution in the following fractions: exchangeable, Fe-Mn oxide, organic and residual ones. The sludge and inorganic Zn addition supported Zn mobility growth and higher Zn retention in Fe-Mn oxides in all tested soils. The influence of the above-mentioned treatments on higher Zn association with soil organic compounds was not explicitly found. Potatoes, wheat and barley accumulated more Zn after its addition into the soils by sludge and inorganic salt. By contrast, Zn content in maize decreased with higher input of Zn into the soil. The highest Zn concentrations were usually observed in plants grown on both Cambisols.

In the experiment conducted in the greenhouse, the different doses of UV-B radiation applied to the two species Avena fatua and Setaria viridis induced changes in leaf and plant morphology. It was a decrease of plant height, fresh mass of leaves, shoots and roots as well as leaf area. Besides, it caused the leaf curling in both of the species. The significant differences between Avena fatua and Setaria viridis in the studied traits were mainly due to the tillering ability of the species. The content of chlorophyll varied considerably. The average values of leaf greenness (SPAD units) for oats were about 43 while for green foxtail 32, respectively. U-VB did not reduce leaf weight ratio, shoot dry matter, shoot to root ratio and leaf area ratio.

Two methods were developed and tested for the measurement of the mowing machine material feed rate (based on the conditioner power input measured by a torque-meter, and/or on the material change in momentum measured by a curved impact plate). The measurements carried out in the year 2001 proved that a very good linear relationship existed between the conditioner power input, output frequency of the apparatus measuring the impact force by means of the impact plate, and the material feed rate through the mowing machine. The calculated R-Squared values were about 0.95. In the year 2002, the impacts of material and condition (parameters) changes on the mowing machine material feed rate measurement accuracy were measured under laboratory conditions. It was evident from the statistical evaluation that changing crop variety, crop maturity, and intensity of conditioning can have a statistically significant influence on the measurement based on the torque-meter. As concerns the impact plate measurement, it was found that it is not possible on the basis of our measurements to determine statistically the influence of the factors tested.

This paper deals with the recent sissoo (Dalbergia sissoo Roxb.) decline in the plain land (locally called as terai) of Nepal. This study has made an attempt to find the possible causal factor of this decline. The study has made some initiative in this aspect and has made a comparative study of 30 different sissoo forest (both natural and plantation) stands. The symptoms of the sissoo decline were found to be varied. But in most of cases, the top dying of crown was found to be the most prevalent. The top dying starts from the top of the tree and progressively proceeds downwards to the stem. The leaves become yellow. Until now, it has been assumed that only the plantation forests have been affected but this study observed the sissoo decline also in natural forest sites. We analysed various components of physical soil characteristics and we did not find any correlation between the physical soil factors and the sissoo decline. We concluded from this study that the soil is not the sole responsible factor involved in the sissoo decline Furthermore, this paper discusses various aspects of the sissoo decline and possible causal factors concerned. Finally, future management strategies regarding the sissoo management are suggested.