Fulltext search in archive

The interaction of manganese with cadmium (Cd) toxicity was studied on maize plants grown in hydroponics. Manganese supplied as MnSO₄clearly alleviated the toxic effect of cadmium on the root growth of maize seedlings. The magnitude of alleviation was dose dependant and total abolition of 10µM Cd toxicity on root growth was observed at Mn/Cd ratio of 20:1. The 12 h pre-treatment with 10μM Cd was generally toxic for nitrate uptake and reduction (both determined in Cd-free media). The beneficial effect of 100μM Mn on this toxicity was confirmed for the low-affinity nitrate uptake system, but on the other hand, Mn alone seems to be slightly toxic for high affinity nitrate uptake system and on the nitrate reductase activity.

This paper addressed the spatial distribution characteristics of organic matter, total nitrogen, extractable phosphorus and extractable potassium in agricultural soils of Northeast China. The related factors were explored using geostatistics and geographic information systems. The results showed that the log-transformed data of the four soil nutrients followed a normal distribution. Soil extractable phosphorus had a higher coefficient of variation. The experimental variogram of the log-transformed data of soil organic matter, total nitrogen and extractable phosphorus was fitted with an exponential model, while soil extractable potassium was fitted to a spherical model. Soil samples from smaller slope gradients had higher organic matter and total nitrogen. Soil type affected the four soil nutrients significantly. Soil samples from dry farming land had significantly higher total nitrogen and extractable potassium than soil from paddy fields, while the contrary was found for extractable phosphorus. Along the Yinma River, soil samples from the western part have statistically higher values for organic matter, total nitrogen and extractable potassium than those collected from the eastern part.

An incubation experiment with addition of EDTA and alfalfa into soils contaminated with heavy metal over 200 years was carried out in order to evaluate the EDTA effects on microbial properties. Alfalfa was added to soils together with EDTA to examine its abilities to improve microbial activities affected by EDTA. The obtained results showed that the addition of EDTA led to a significant decrease of microbial biomass C during the first 24 days of incubation. At the end of the experiment the microbial biomass C significantly increased quite close to the original level. The EDTA amendment caused, probably due to the toxic effects, a significant increase in respiratory activities and of the metabolic quotient qCO₂. An addition of alfalfa significantly improved the microbial biomass C contents in arable soils treated together with EDTA. Both, respiratory activities and qCO₂ significantly increased after the soil treatment with EDTA together with alfalfa. EDTA alone decreased the microbial biomass, alfalfa alone as organic substrate was mineralised and utilised by soil microorganisms for their metabolism.

Over 2004-2006, effects of mineral fertilisers (60 N + 30 P + 60 K kg/ha or 120 N + 30 P + 60 K kg/ha) and farmyard manure (12 or 24 t/ha) application on biological and chemical properties of soil were studied in seminatural grassland. The research trial was established at Radvaň site, central Slovakia (altitude 480 m, loamy to sandy-loamy Cambisol). These parameters were investigated during the growing seasons: CO₂ production, intensity of total N mineralisation (TMN), the rate of nitrification (NIT), total C content in microbial biomass (MB-C), C_ox, N_t, P, K, Mg and the humic acids to fulvic acids ratio (HA:FA). At the application of mineral fertilisers, the highest N rate significantly increased TMN and NIT, mainly in 2004 and 2005. The manure application showed the strongest effects on the biological parameters. The manure rate of 12 t/ha significantly increased the soil respiration in 2005 and 2006 as well as TMN and NIT throughout the research. The manure application increased also the soil pH, MB-C, N_t, Mg, P and C_ox.

The paper deals with the possibilities of arsenic analysis in the soil. The aim is the selection and verification of the methods for analysis of As in the soil, which seem to be suitable for risk evaluation based on the increased As soil load. Economical and analytical availability of the methods is an important criterion. A sample set of 6 heavily contaminated soils was used to compare application potential of prevalent as well as less common procedures for determination of arsenic forms in soils. The results showed that substitution of analytically more demanding As total content analysis and sequential analysis for simple extraction using one-off agents seemed to be promising in many cases. The comparison and evaluation of statistical correlation of used methods of As analysis in the soil was realised. The results suggested that using the combination of simple 1M NH₄NO₃ extraction and determination procedure for amorphous Fe forms in the soil (the Tamm method) was suitable for the risk assessment stemming from the As contamination without necessity of the application of more complicated sequential extraction procedures.

Mercury (Hg) is one of the major pollutants in soils because of the annual import of toxic Hg into the agricultural lands. The aims of the present studies are to investigate the effect of Hg on chlorophyll content in winter wheat var. jinan No. 17. Moreover, calcium (Ca) levels and bioaccumulation of Hg in wheat leaves were studied with the technique of inductively coupled plasma sector field mass spectrometer (ICP-SF-MS). The study conducted a range of Hg concentrations from 0~500 mg Hg/kg in the dry weight soil. The soil was artificially contaminated with Hg as follows: 0, 100, 200, and 500 mg Hg/kg as HgCl₂. At early stages of the wheat growth, both low and high concentration of Hg stimulates chlorophyll content, but inhibits chlorophyll content at later stages of the wheat growth. Furthermore, the concentrations of Ca and Hg in wheat leaves increased with the increasing concentration of Hg on the thirty-fourth day with the technique of ICP-SF-MS. The results indicate that Hg can accelerate the absorption of Ca in winter wheat and Hg stress may affect Ca levels in wheat leaves.

Formerly arable luvic chernozem set aside for ten years (1997-2006) with different herbaceous cover (grass, legumes and their mixtures) and agronomical practices (mulching and cut/harvesting) was studied. The experimental plot was maintained as black, spontaneous and controlled fallows from 1997 until July 2003 (BD period). In July 2003 the plots were desiccated by glyphosate herbicide and were run as a black fallow until August 2004 (AD). The last period (AG) was characterized by monoculture of Italian ryegrass cut/harvested twice a year until October 2006. The experimental soils were characterized with 18 parameters. Mulched plots in all periods (BD, AD and AG) were evaluated as highly microbial active plots. The black fallow (BD) permanently maintained by glyphosate herbicide was the lowest in biological parameters. The desiccation caused a highly significant increase (P < 0.01) of nitrates in topsoil, but in following period (AG) their significant decrease was detected. Desiccation enhanced carbon immobilization into microbial cells especially on mulched and cut/harvested sites (BD, AD). Due to mulching accumulation of soil organic matter highly significantly increased (P < 0.01). This induced a highly significant (P < 0.01) increase in the basal respiration (AD, AG) as the soil organic matter accumulated in the period BD was intensively mineralized.

Producers in highland and semiarid regions have difficulty in increasing diversity in crop rotations due to unfavorable conditions imposed by cool temperatures, inadequate rainfall, and shorter growing periods. In such conditions, safflower appears as a promising alternative because it is cold and drought tolerant. The objective of this study was to determine the responses of the hybrid and open-pollinated safflower genotypes to irrigated and non-irrigated conditions in a highland environment. For this reason, the field research was performed during the years of 2001 and 2002 in eastern Anatolia, Turkey. According to the results of the study, safflower genotypes tested were well adapted to the cool and short-season conditions in this region. The response of seed yield to genotype varied depending on the growing seasons. The non-irrigated plants produced nearly the same seed yield as irrigated ones. Average seed yields of safflower genotypes tested were 914.3 and 928.0 kg/ha in 2001, and 1143.6 and 1139.9 kg/ha in 2002 years for irrigated and non-irrigated experiments, respectively. In general, the genotypes differed in all of the investigated traits. In both irrigated and non-irrigated experiments genotype × year interactions were very significant for all parameters. This research shows that in semiarid and highland environments safflower has a big potential value as an oilseed crop under dryland conditions.

The objective of this study was to determine the effect of foliar urea applications on quality, growth, mineral content and yield of broccoli under field conditions in 2003, 2004 and 2005. Broccoli cultivars AG 3317 and AG 3324 were treated with foliar urea applications at different concentrations (0.0, 0.4, 0.8 and 1.0%). Foliar applications of urea, especially 0.8 and 1.0% resulted in larger heads, weightier heads and plants as well as higher plants. Conversely, the greatest head and leaf dry matter contents were obtained with no fertilizer-nitrogen application. SPAD chlorophyll readings that were measured in the third year increased with elevated urea concentrations. In regard to the nutrient content, it can be interfered that soil nitrogen fertilization and foliar urea applications increased the content of almost all nutrients in leaves and heads of both broccoli cultivars in three experiment years. Generally, the greatest values were obtained from 1.0% urea application for both cultivars. It results from the study that for optimum yields 0.61 and 0.96% concentrations of urea sprays could be successfully used to obtain better growth and yield in broccoli cultivars AG 3317 and AG 3324, respectively.

By reference to the Eternal Rye trial in Halle, Germany, as an example, it is demonstrated that long-term trials provide indispensable information for contemporary and future land use research. These trials serve as tools for the examination of cultivation measures or the effects of climate on nutrient dynamics and mobilization, microbial biodiversity, mineral composition or soil formation processes. They are therefore essential for the evaluation of land-use strategies or climatic change and, because of that, can provide more accuracy in related political considerations.

In order to study the characteristics of element values in the cell of plants and soils and their relationships that would help to evaluate the biogeochemical effect of soil on the element contents in the cells of plants in the same environment of Southwestern China, the soil samples were collected for analysis and the weight and atom percentage of elements (WT% and AT%) in the leaves of two different species of Flos Lonicerae were analyzed by the electron probe (EDX-9100). The results of soil analysis show that the nutrient element contents in the soil are determined by the liable content of elements, which were arranged as: Ca > Mg > Cu > Mn > K > Na > P > B > SiO₂ > Zn > Fe, even though the total element values in soil of different horizons were arranged as: SiO₂ > Fe > Ca > Mg > K > Na > Mn > P > Zn > B > Cu. It indicates that karst environment is composed of soluble calcium-rich rock and soil scarcity. Moreover, the migratory velocity and availability of elements are also determined by their coefficient variability. According to statistical results, Ca, Mn and P in the soil have high coefficient variability, reflecting its background of karst soil. Based on the electron probe, it is shown that the content of Ca is higher while Mg is the lowest in the cell of two different species of Flos Lonicerae (r = -0.156, P < 0.05) and the content of P in the cell is inferior to Ca (r = 0.868, P < 0.01). By studying the relationship of soil and the plants, it can be seen that these results are probably caused by the characteristics of local biogeochemistry. Ca is mainly absorbed by plant with the help of transpiration and accumulated in the cell, and thus becomes a predominant element in the cell. The accumulation of Ca in cell of plant will affect the absorbency and the content of other elements in the cell of Flos Lonicerae, resulting in the different contents of other elements in the Flos Lonicerae through synergistic and antagonistic action, followed by the affected quality and officinal value of the Flos Lonicerae.

Basmati rice (Oryza sativa L.) cultivars viz. PRH-10 (pusa rice hybrid-10) and PS-2 (Pusa Sugandh-2) were grown under two different day/night temperatures (31/24°C, 35/28°C) at ambient (370 μmol/mol) and elevated (550 μmol/mol) carbon dioxide (CO₂) concentration, respectively, to characterize how an increase in CO₂ and temperature affects rice photosynthesis and carbohydrate metabolism. At elevated CO₂, the photosynthetic rates increased under both the temperature regimes, compared with plants grown at ambient CO₂. The photosynthetic rate, sucrose-P synthase (SPS) activity and accumulation of soluble sugars and starch were higher in PRH-10 (pusa rice hybrid-10), compared to PS-2 (Pusa Sugandh-2). Elevated temperature decreased the photosynthetic rates both under ambient and elevated CO₂ conditions. The SPS (sucrose-P synthase) activity and the accumulation of soluble sugars and starch were enhanced at elevated CO₂ under both temperature regimes compared with plants grown at ambient CO₂. The up-regulation of SPS (sucrose-P synthase) under elevated CO₂ and temperature would be beneficial for growth and productivity of rice plants for the future climatic conditions.

The apparent uptake of mineral nitrogen (N_min) from top- and subsoil layers during the growth of winter wheat (Triticum aestivum L.) was studied in Prague-Ruzyne on clay loam Chernozem soil in years 1996-2003. Two (N0, N1) and three treatments, unfertilized (N0), fertilized with 100 kg (N1) and 200 kg (N2) nitrogen per hectare were observed in years 1996-2000 and 2001-2003, respectively. The apparent uptake of nitrogen from soil layers was calculated from the changes of N_min content between sampling terms. Most of available mineral N in the soil down to 90 cm was almost fully depleted between tillering and anthesis in treatment N0. The uptake from subsoil layers was delayed and it continued during the period of grain filling in fertilized treatments. Nitrogen fertilization reduced utilization of N from subsoil. The apparent uptake of N from the zone 50-120 cm ranged from 21 to 62 kg N/ha in N0 and from 15 to 60 kg N/ha in N1 in years 1996-2000. In years 2001-2003 the corresponding values (50-130 cm) were 24-104 kg, 43-130 kg and 29-94 kg N/ha in treatments N0, N1 and N2, respectively. The uptake from 120 (130)-150 cm was around zero in a half of experimental years, and it reached at maximum 12 kg/ha in N0 in 1997. There was a strong linear relation between the amount of N_min in spring and the depletion of nitrogen from the zone 50-120 (130) cm, R² = 0.94, 0.91 and 0.99 in N0, N1 and N2, respectively.

The influence of mycorrhizal fungi on field pea green mass yield, dry matter yield, grain yield, number of pods per plant, number of grains per pod, average number of plants per m², grain concentration of nitrogen, phosphorus and potassium were studied in the greenhouse during two investigative years. The best results with all parameters were obtained in both investigative years by seed inoculation with the mycorrhizal species G. mossae. The exceptions were mean green mass yield, dry matter yield and the number of grains per pod in the second investigation year (irrigation rate - 240 mm/m²) where better results were achieved by seed inoculation with species G. intraradices. The highest green mass yield obtained by seed inoculation with mycorrhizal species Glomus mossae was 671.45 g/m², dry matter yield 59.40 g/m², grain yield 346.20 g/m² whereas grain nitrogen concentration was 4.08%. Far better results of all yield and quality indicators of this plant compared to non-mychorrized variants were accomplished by mycorrized variants in water lacking conditions.

Four conservation methods were compared on grassland unused for 30 years: 1. control (unused grassland); 2. one cut, herbage mass was spread for mulch; 3. one cut, herbage mass was removed; 4. two cuts, herbage mass were removed. Experiments were carried out during 1996-2000 at the Kaltinenai Research Station of the Lithuanian Institute of Agriculture in a hilly region of the Zemaiciai Uplands of West Lithuania, on a hilltop and hill slope. During the experimental period an increase in the number of shoots of each botanical group (grasses, legumes and forbs) were identified in all treatments. The highest increase in the total number of grass shoots was characteristic of the controlled treatment on both parts of the hill. At the end of the conservation period, 38 herb species were identified in the trial. Treatments 1 and 2 were richer in floristic diversity (27-33 species) compared with treatments 3 and 4 (20-25 species). The treatments on the hill slope had a more diverse species composition than those on the hilltop. During the grassland conservation period the content of legumes in the herbage mass increased from 0 to 27.7% in the swards where cut herbage was removed.

Malt barley production requires a technology increasing nitrogen use efficiency, because of a high sensitivity of barley total grain yield and quality parameters to external growth factors. In the conducted study an effect of two P fertilizers on the background of N application on total and technological grain yields were studied. The highest total grain yield was harvested on plots fertilized with 60 kg N/ha, irrespective of the P fertilizer type. However, the technological grain yield showed a high year-to-year variability; the highest was recorded in 2001 on the plot fertilized with 60 kg N/ha and the P-PAPR fertilizer. The N and S concentrations and N:S ratios in immature grains at harvest were used to evaluate both yield types. Nitrogen concentration in the final total yield allowed making yields prognosis with the highest probability. The maximum yields of technological malt barley were attainable provided that total S concentration in immature grains at harvest was above 0.23% and the N:S ratio was narrower than 8.0.

The aim of the present paper was to determine the impact of gypsum treatment of soils on initial growth and nutrient uptake by spring barley. Topsoil from 36 different farmed fields was used for the research. Two variants were established for each soil: control - without gypsum application, and response variant - with the application of 3.3 ppm CaSO₄.2 H₂O. Barley was grown on these soils for 21 days in a plant growth chamber under controlled conditions of cultivation. Concentrations of nutrients (N, NO₃^-, P, S, K, Mg, Ca, Na, Fe, Mn, Zn, Cu, B and Mo) were determined in the yield of barley shoot biomass. Paired t-test was used for the evaluation of results. After the gypsum treatment the yield of barley shoot biomass was significantly higher (by 15% on average) and nitrogen utilisation was better on all soils. The concentration of sulphur increased five times on average and Ca concentration increased by 22%. Significant increases were measured in Mg, Mn and Cu. Insignificant differences were recorded in K, Na, Fe and Zn. The uptake of anion nutrients (P, B and Mo) was influenced significantly. The concentration of P and Mo decreased on average by 28% and 31%, respectively. B concentration was higher by 10% on average.

A pot greenhouse experiment was performed to determine the effect of contamination with nickel interacting with other heavy metals on the microbiological properties of soil. The study was conducted on samples of soils classified under natural conditions as typical Eutric Cambisol developed from heavy loamy sand and typical Eutric Cambisol developed from light silty loam. Soil material was contaminated with nickel in the amount of 50 and 200 mg Ni²⁺/kg. The treatments with 200 mg Ni²⁺/kg were additionally contaminated with other heavy metals (Zn²⁺, Cu²⁺, Pb²⁺, Cd²⁺, Cr⁶⁺), in the amount of 50 mg/kg soil. The following treatments, in which the soil was contaminated with heavy metals applied alone or in combinations, were compared in the study: Ni, Zn, Cu, Pb, Cd, Cr, NiZn, NiCu, NiPb, NiCd, NiCr, NiZnCu, NiZnPb, NiZnCd, NiZnCr, NiZnCuPb, NiZnCuCd, NiZnCuCr, NiZnCuPbCd, NiZnCuPbCr, NiZnCuPbCdCr. The experiment was carried out in four replications. A microbiological analysis was performed on days 28 and 56. The tested crop was oat. It was found that the impact of particular heavy metals on microbiological properties of soils depended on their type, interactions between nickel and zinc, copper, lead, cadmium and chromium (VI), date of analysis and soil species. Soil contamination with heavy metals reduced the population size of Azotobacter spp. The counts of other microbial groups, i.e. copiotrophic bacteria, spore-forming copiotrophic bacteria, oligotrophic bacteria, spore-forming oligotrophic bacteria, ammonifying bacteria, nitrogen immobilizing bacteria, cellulose-decomposing bacteria, Arthrobacter spp., Pseudomonas spp., actinomyces and fungi, showed varied susceptibility to heavy metals.

Changes in the zinc content in the meadow sward were studied in a long-term fertiliser experiment set up on a mountain meadow (20°54'E, 49°24'N) in 1968. The experiment is localized at 720 meters above sea level on the soil which belongs to Dystric Cambisols and comprises 8 fertiliser treatments in two series: 0Ca and + Ca (Table 1). In the course of the experiment the Zn content in the sward decreased and the time factor was of greater consequence than fertilization, P content in the sward or soil and acidification. In mountain meadow communities shaped by a long-term (over 30 years) NPK treatment and at yields between 6.7 and 7.1 t/ha the annual quantity of absorbed Zn ranged between 233 and 256 g Zn/ha dry weight. During the experimental period the biggest amount of Zn removed with the sward yield exceeded 500 g Zn/ha annually. In the limed series at slightly bigger yields the quantity of Zn removed with the yield was over 10% lower in objects receiving NPK fertilization than on the same treatments in the unlimed series. Liming is able to reduce soil Zn abundance.

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 objective of this study was to examine and demonstrate how harvesting age (flower age) contribute to the variations in the quality of Echinacea purpurea (L.) Moench. The effects of different flower developmental stages on caffeic acid derivatives and isobutylamide content are described. These phytochemicals were extracted from fresh plants with 60% ethanol and quantified by the HPLC analysis. The results revealed that the quality of Echinacea is strongly influenced by the flower developmental stages. The highest content of both hydrophilic and lipophilic components in the anthodium of Echinacea plants were found in the third (mature) developmental stage, which is regarded as the optimum one for the harvest to obtain optimum yield levels.

Soils were sampled from the plots with four variants of fertilisation: Nil - without fertilisation, NPK - mineral fertilisation, FYM - farmyard manure, FYM + NPK - farmyard manure with mineral fertilisation, and two variants of crop rotation: field IV - classical 9-year crop rotation, field B - 2-year rotation of alternative growing. Determination of urease, CFU of Azotobacter spp. and potential nitrogenase activity was conducted during the period 1999-2004. The urease activity was positively affected by manure fertilisation (FYM) and by the combination of FYM + NPK. The statistically significantly highest counts of Azotobacter spp. and the highest nitrogenase activity were determined on field B in variants FYM and FYM + NPK. The results show that there was a higher amount of accessible nitrogen present on field IV than on field B. This might explain the lower counts of Azotobacter spp. and therefore the lower nitrogenase activity. According to our results, activity of urease, CFU of Azotobacter spp. and potential nitrogenase activity are very closely connected with N inputs.

In the paper yield of dry matter and some morphological features of four fast growing willow coppice genotypes harvested in one, two, three and four years harvesting cycles are presented. In the experiment an average yield amounted to 16.79 t/ha/year. The highest yield was recorded for Salix viminalis × S. viminalis lanceolata (22.89 t/ha/year). Genotype Salix triandra gave a yield lower by factor 3 compared to Salix viminalis × S. viminalis lanceolata. For the following genotypes: Salix viminalis × S. viminalis lanceolata, Salix viminalis var. gigantea and Salix viminalis var. regalis it was found the yield increased as harvesting cycle increased from one to four years while the opposite was found for genotype Salix triandra. It can indicate that Salix triandra is not suitable for intensive growing on arable lands, especially in two, three or four years harvest cycles. Mean plant height amounted to 4.63 m and stem diameter 20.48 mm. The tallest plants (769 cm) with the thickest stem (diameter of 37.43 mm) were found for genotype Salix viminalis × S. viminalis lanceolata harvested quadrennially. At harvest water content amounted to 49.87% and the highest value was found for the shortest harvesting annually.

The influence of various forms of farming on unmanaged grasslands was monitored with regard to the accumulation of the above-ground biomass (litter + mulching) and its influence on the leakage of rainfall and the amount of elements in lysimetric waters. In 2001-2005, the highest accumulation was observed in variants 1× mulched in the later term and on green fallow (on average 2.11-1.13 t of dry matter/ha). In comparison with the control site, a conclusive increase always occurred. An interannual increase of dry matter amounted to 0.4-5.2% of the total above-ground biomass. A negative correlative dependency on rainfall leakage on this material was discovered; at a depth of 0.4 m 4-10% of the rainfall leaked, but it had a significant influence on the wash out of Ca, Mg and S. The leakage of water affected a wash out of N_min, P, K, Ca, Mg and S more than the weight of dry matter of the above-ground biomass. With the exception of P, the elements showed a downward tendency over five years. The above-mentioned forms of farming annually increased the accumulation of the above-ground biomass by 0.05-0.16 t of dry matter/ha; however, they do not endanger underground waters by washing out minerals. After a five-year period, a disturbance of the ecological stability of grassland did not occur.

Soybean cultivation in many zones of India shows occurrence of native rhizobia besides other exotically adapted strains. In the current study, 22 rhizobial isolates (recovered from 12 different soybean growing sites) and 8 reference strains were selected for biochemical and metabolic characterization. Of 22 isolates, 18 were recovered as fast growing isolates while the rest were slow growing based on bromothymol blue (BTB) test. Unlike earlier belief that rhizobia have no ability to grow on glucose peptone agar medium, in this study, some isolates and some reference strains grew well on this medium. Similarly, when all the isolates were subjected to ketolactose test, some of the isolates were found to show growth on the medium. In contrast, based on C-utilization pattern (15 carbohydrates) a remarkable metabolic diversity was observed among the rhizobial isolates recovered in the study. The clustering and matching analysis showed that most of isolates were matching with slow growing reference strains, a few were with fast growing reference strains and some were found to be unique and hence not matching with any of reference strains. Such analysis suggests the occurrence of metabolically distinct types of rhizobia besides commonly known types (B. japonicum, B. elkanii and S. fredii) of soybean rhizobia and further validation is suggested through 16SrRNA gene sequencing technique.

Deoxynivalenol (DON) is the most prevalent Fusarium toxin in Czech wheat samples and therefore forecasting this mycotoxin is a potentially useful tool to prevent it from entering into food chain. The data about DON content in wheat grain, weather conditions during the growing season and cultivation practices from two field experiments conducted in 2002-2005 were used for the development of neural network model designed for DON content prediction. The winning neural network is based on five input variables: a categorial variable - preceding crop, and continuous variables - average April temperature, sum of April precipitation, average temperature 5 days prior to anthesis, sum of precipitation 5 days prior to anthesis. The most important input parameters are the preceding crop and sum of precipitation 5 days prior to anthesis. The weather conditions in April, which are important for inoculum formation on crop debris are also of important contribution to the model. The weather conditions during May and 5 days after anthesis play only an insignificant role for the DON content in grain. The effect of soil cultivation was found inferior for model function as well. The correlation between observed and predicted data using the neural network model reached the coefficient R² = 0.87.

The risk of Pb contaminated soil after treatment with different remediation techniques was assessed. Soil vitrification (microwaves) reduced Pb orally available from the stomach and intestinal phase measured by a physiologically based extraction test. Solidification of Pb (Slovakite) did not reduce the concentration of orally available Pb and increased the Pb uptake by Thlaspi goesingens for 2-times compared to plants grown on the original soil. Soil extraction with 40 mmol/kg EDTA removed 57.6% of Pb. However, the concentration of orally available Pb and Pb uptake by T. goesingens increased. The concentration of mobile soil Pb also increased for 14-times measured by a toxicity characteristic leaching procedure. Soil leaching with 10 mmol/kg biodegradable chelator [S,S] ethylenediamine disuccinate and using a horizontal permeable reactive barrier for Pb accumulation from the washing solution removed 17.8% of Pb, but increased Pb uptake by T. goesingens by 3-times and slightly increased the concentration of Pb in the intestinal phase. Leaching did not significantly effects Pb availability from the stomach phase or Pb mobility.

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.

The aim of the study was to determine the effect of soil contamination with diesel oil (3, 6, 9, 12 and 24 g/kg soil) on the yield and the content of macroelements in oat and maize cultivated in soil supplemented with nitrogen and sawdust. The correlation between the content of macroelements in the crops and the soil enzymatic activity was also determined. High doses of diesel oil had a definite negative effect on the content of all macroelements in oat, excluding phosphorus. The presence of diesel oil had a favourable effect on the accumulation of most of macroelements in the above-ground parts of maize. Nitrogen application to the soil caused an increase in the content of nitrogen and in the accumulation of calcium and magnesium in the above-ground parts of both crops as well as an increase in sodium content in maize. Sawdust applied to the soil had a considerably lower effect (several to less than 20%) on the content of macroelements in plants. A correlation between the activity of urease and acid and alkaline phosphatase in the soil and the content of macroelements in plants cultivated in diesel oil contaminated soil was observed. This correlation was positive only in the case of alkaline phosphatase activity and phosphorus content in oats.

An endophytic fungus of soyabean (Glycine max) roots, Fusarium oxysporum, was used to study its activity under heavy metals (Cd²⁺, Mn²⁺ and Zn²⁺) stress and the role of rock phosphate (RP) in alleviation of the stress. F. oxysporum growth, amino acids and protein were increased by increasing RP concentration (1-6 g/l) after 8 and 14 days. Heavy metals (HM) have a stressing effect on F. oxysporum - a significant decrease of amino acids, protein and accumulation of sugar at 1mM/l follows a descending order of Cd²⁺ > Mn²⁺ > Zn²⁺. RP is altering the stressing effects of metal on F. oxysporum by a significant growth improvement at 3 and 6 g/l RP, increase of amino acids, protein and decrease of sugar. The solubilization of RP increased under HM application, which may be attributed to an increase of the adsorption of HM by increasing RP concentration. RP has the highest adsorption affinity for Cd²⁺ (81%) followed by Zn²⁺ (71%) and Mn²⁺(55%).