Template-Type: ReDIF-Article 1.0 Author-Name: R. Kodešová Author-Workplace-Name: Czech University of Agriculture in Prague, Czech Republic Author-Name: J. Kozák Author-Workplace-Name: Czech University of Agriculture in Prague, Czech Republic Author-Name: O. Vacek Author-Workplace-Name: Czech University of Agriculture in Prague, Czech Republic Title: Field and numerical study of chlorotoluron transport in the soil profile Abstract: The transport of chlorotoluron in the soil profile under field conditions was studied. The herbicide Syncuran was applied on a four square meter plot using an application rate of 2.5 kg/ha active ingredient. Soil samples were taken after 119 days to study the residual chlorotoluron distribution in the soil profile. HYDRUS-1D (Šimůnek et al. 1998) was used to simulate water movement and herbicide transport in the soil profile. Soil hydraulic properties and their variability were studied previously by Kutílek et al. (1989). The solute transport parameters, like the adsorption isotherm and the degradation rate, were determined in the laboratory. The Freundlich and Langmuir equations were used to fit the experimental data points of the adsorption isotherm, and the affect of each type of adsorption isotherm equation on the solute transport was studied. The chlorotoluron concentrations in soil water tended to be higher for the simulation performed with the Freundlich isotherm then that of the model using the Langmuir isotherm. In both cases, the solution did not pass a depth of8 cm. The simulated chlorotoluron concentrations in soil samples were higher then the observed concentrations when the chlorotoluron degradation was assumed to be in soil water only. Assumption of the solute degradation in both in the solid and the liquid phase significantly improved the accuracy of the solution. The different characters of the simulated and observed chlorotoluron distributions can probably be attributed to the preferential flow of water and solute in the soil profile and by variability of the transport parameters. Keywords: herbicide, chlorotoluron, adsorption isotherm, degradation rate, solution transport, field and numerical studies Journal: Plant, Soil and Environment Pages: 333-338 Volume: 50 Issue: 8 Year: 2004 DOI: 10.17221/4040-PSE File-URL: http://pse.agriculturejournals.cz/doi/10.17221/4040-PSE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/pse-200408-0001.txt Handle: RePEc:caa:jnlpse:v:50:y:2004:i:8:id:4040-PSE Template-Type: ReDIF-Article 1.0 Author-Name: L. Borůvka Author-Workplace-Name: Czech University of Agriculture in Prague, Czech Republic Author-Name: O. Drábek Author-Workplace-Name: Czech University of Agriculture in Prague, Czech Republic Title: Heavy metal distribution between fractions of humic substances in heavily polluted soils Abstract: Soil organic matter is important in controlling heavy metal behaviour in soils. This study aims to determine the distribution of organically bound Cd, Pb, and Zn between humic and fulvic acids in 20 samples of heavily polluted Fluvisols. Traditional procedure of alkaline sodium hydroxide/pyrophosphate extraction of humic substances with consequent humic acids precipitation by acidification was used. All of the three metals were bound predominantly on fulvic acids (mean share was 98.4, 82.0, and 95.7% of total organically bound Cd, Pb, and Zn content, respectively). Mainly the level of pollution controlled the amount of metals bound on fulvic acids. On humic acids, a limited amount of specific sorption sites for the metals is expected. Lead content bound on humic acids was negatively correlated with soil pH. The results suggest relatively high potential mobility of organic fractions of heavy metals in soils under this study. The selectivity of alkaline extracting agent is briefly discussed. Keywords: heavy metals, humic acids, fulvic acids, soil pollution, speciation Journal: Plant, Soil and Environment Pages: 339-345 Volume: 50 Issue: 8 Year: 2004 DOI: 10.17221/4041-PSE File-URL: http://pse.agriculturejournals.cz/doi/10.17221/4041-PSE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/pse-200408-0002.txt Handle: RePEc:caa:jnlpse:v:50:y:2004:i:8:id:4041-PSE Template-Type: ReDIF-Article 1.0 Author-Name: L. Mládková Author-Workplace-Name: Czech University of Agriculture in Prague, Czech Republic Author-Name: L. Borůvka Author-Workplace-Name: Czech University of Agriculture in Prague, Czech Republic Author-Name: O. Drábek Author-Workplace-Name: Czech University of Agriculture in Prague, Czech Republic Title: Distribution of aluminium among its mobilizable forms in soils of the Jizera Mountains region Abstract: Labile Al forms can be dangerous in acid soils due to their potential toxicity to plants. This paper deals with the distribution of exchangeable, weakly organically bound, and total organically bound Al forms in soils on 98 sites of the Jizera Mountains region. For the extraction of these Al forms, 0.5M KCl (AlKCl), 0.3M CuCl2 (AlCuCl2), and 0.05M Na4P2O7 (AlNa4P2O7) solutions were used, respectively. Aluminium concentrations in all extracts were determined by means of ICP-OES. Following mean concentrations of Al forms were found in the O and B horizons (mg/kg): AlKCl - 1236 and 832, AlCuCl2 - 4268 and 1945, and AlNa4P2O7 - 5043 and 8420. Basic soil characteristics were determined by commonly used methods. Their influence on Al forms distribution was assessed. Factor analysis showed that the most important soil factors controlling Al forms distribution were soil reaction and the total content of Ca (or Ca and Mg in the B horizon). Keywords: aluminium, labile Al forms, forest soils, soil acidification, Al extraction Journal: Plant, Soil and Environment Pages: 346-351 Volume: 50 Issue: 8 Year: 2004 DOI: 10.17221/4042-PSE File-URL: http://pse.agriculturejournals.cz/doi/10.17221/4042-PSE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/pse-200408-0003.txt Handle: RePEc:caa:jnlpse:v:50:y:2004:i:8:id:4042-PSE Template-Type: ReDIF-Article 1.0 Author-Name: V. Penížek Author-Workplace-Name: Czech University of Agriculture in Prague, Czech Republic Author-Name: L. Borůvka Author-Workplace-Name: Czech University of Agriculture in Prague, Czech Republic Title: Processing of conventional soil survey data using geostatistical methods Abstract: The aim of this study is to find a suitable treatment of conventional soil survey data for geostatistical exploitation. Different aims and methods of a conventional soil survey and the geostatistics can cause some problems. The spatial variability of clay content and pH for an area of 543 km2 was described by variograms. First the original untreated data were used. Then the original data were treated to overcome the problems that arise from different aims of conventional soil survey and geostatistical approaches. Variograms calculated from the original data, both for clay content and pH, showed a big portion of nugget variability caused by a few extreme values. Simple exclusion of data representing some specific soil units (local extremes, non-zonal soils) did not bring almost any improvement. Exclusion of outlying values from the first three lag classes that were the most influenced due to a relatively big portion of these extreme values provided much better results. The nugget decreased from pure nugget to 50% of the sill variability for clay content and from 81 to 23% for pH. Keywords: conventional soil survey, geostatistics, data processing, spatial variability Journal: Plant, Soil and Environment Pages: 352-357 Volume: 50 Issue: 8 Year: 2004 DOI: 10.17221/4043-PSE File-URL: http://pse.agriculturejournals.cz/doi/10.17221/4043-PSE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/pse-200408-0004.txt Handle: RePEc:caa:jnlpse:v:50:y:2004:i:8:id:4043-PSE Template-Type: ReDIF-Article 1.0 Author-Name: P. Dlapa Author-Workplace-Name: Faculty of Natural Science, Comenius University, Bratislava, Slovakia Author-Name: S.H. Doerr Author-Workplace-Name: Faculty of Natural Science, Comenius University, Bratislava, Slovakia Author-Name: Ľ. Lichner Author-Workplace-Name: Faculty of Natural Science, Comenius University, Bratislava, Slovakia Author-Name: M. Šír Author-Workplace-Name: Faculty of Natural Science, Comenius University, Bratislava, Slovakia Author-Name: M. Tesař Author-Workplace-Name: Faculty of Natural Science, Comenius University, Bratislava, Slovakia Title: Effect of kaolinite and Ca-montmorillonite on the alleviation of soil water repellency Abstract: The effects of adding 1-3% (weight) kaolinite or Ca-montmorillonite on the wettability of silica sand, made highly water repellent with stearic acid, was studied during wetting and prolonged drying phases at 50°C. The persistence of water repellency was estimated with the water drop penetration time (WDPT) test. After wetting water repellency disappeared in all the samples. During the drying phase, water repellency re-appeared in all samples (untreated and clay-treated) as the water content decreased below 1%. Repellency did, however, not reach pre-wetting levels. The effect of clay additions on water repellency differed strongly between the two clay types. Kaolinite reduced WDPT, while Ca-montmorillonite caused an increase in WDPT in the already highly repellent sand. Potential mechanisms for the alleviation effectiveness of kaolinite are proposed, with key factors being the high adhesion forces between water and clay mineral surfaces, and the ability kaolinite to disperse. In the case of Ca-montmorillonite, its lower affinity for water may lead to a displacement of water molecules at mineral surfaces by amphiphilic organic compounds, which may result in increased repellency. This phenomenon clearly requires further investigation. Keywords: water repellency, kaolinite, Ca-montmorillonite, stearic acid Journal: Plant, Soil and Environment Pages: 358-363 Volume: 50 Issue: 8 Year: 2004 DOI: 10.17221/4044-PSE File-URL: http://pse.agriculturejournals.cz/doi/10.17221/4044-PSE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/pse-200408-0005.txt Handle: RePEc:caa:jnlpse:v:50:y:2004:i:8:id:4044-PSE Template-Type: ReDIF-Article 1.0 Author-Name: M. Stránská Author-Workplace-Name: Czech University of Agriculture in Prague, Czech Republic Title: Successional dynamics of Cynosurus pasture after abandonment in Podkrkonoší Abstract: Between 1996-2002, successional dynamics on an abandoned pasture in Přední Ždírnice (lat. 50°32'N, long. 15°40'E) was examined. A 7-year study was performed on the abandoned mesotrophic pasture classified as Cynosurion Tüxen 1947 at the start of the study. Two permanent plots (100 m2) were established and sampled three times a year; changes in plant species composition (species cover) and plant species diversity (species number) were studied. Species assemblages of the Cynosurus pasture were described, E1 (herb layer) and E2 (shrub layer) covers were calculated and a secondary succession in the plant community was evaluated. Abandonment caused the decrease in the cover of the species sensitive to shading - e.g. Taraxacum sect. Ruderalia, Trifolium repens, Lathyrus pratensis, Plantago major, Stellaria graminea, Vicia cracca. Contrary to this, the cover of Calamagrostis epigejos, Rubus sp., Galium album, Galium verum, Knautia arvensis, Veronica chamaedrys increased, probably due to their ability to spread by clonal growth and as a result of the competitive relationships in the plant community. A big production of Calamagrostis epigejos litter may be the outcome of a significant decrease (by 9%) in E1 cover (P = 0.04). Although the grassland was invaded by ruderal and weedy species (Apera spica-venti, Myosotis arvensis, Veronica arvensis) and by shrubs Crataegus sp. and Rosa sp. (an increase by 16%), an increase in species number was not significant. Phytosociologically, the Cynosurion Tüxen 1947 community came closer to the Arrhenatherion Koch 1926 alliance. Keywords: grassland, successional dynamics, Cynosurus pastures, land use, abandoned meadows, Podkrkonoší Journal: Plant, Soil and Environment Pages: 364-370 Volume: 50 Issue: 8 Year: 2004 DOI: 10.17221/4045-PSE File-URL: http://pse.agriculturejournals.cz/doi/10.17221/4045-PSE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/pse-200408-0006.txt Handle: RePEc:caa:jnlpse:v:50:y:2004:i:8:id:4045-PSE Template-Type: ReDIF-Article 1.0 Author-Name: P. Fuksa Author-Workplace-Name: Czech University of Agriculture in Prague, Czech Republic Author-Name: J. Hakl Author-Workplace-Name: Czech University of Agriculture in Prague, Czech Republic Author-Name: D. Kocourková Author-Workplace-Name: Czech University of Agriculture in Prague, Czech Republic Author-Name: M. Veselá Author-Workplace-Name: Czech University of Agriculture in Prague, Czech Republic Title: Influence of weed infestation on morphological parameters of maize (Zea mays L.) Abstract: The influence of various ways of regulation in weed infestation of silage maize stands was studied in 1999-2001. Four variants of stands were compared: 1. without weed eradication (check), 2. mechanically weeded throughout the whole vegetation period, 3. mechanically weeded from the beginning of vegetation till the phase of 5th leaf and later on without protection, 4. chemical weeding. The yield of dry mass and morphological characters (height of plants, stem diameter, number of ears per plant etc.) show the substantial negative effect of weed infestation upon the studied parameters. The yield from the check variant reached 8.09 t/ha, from the 2nd variant 13.24 t/ha, from the 3rd variant 11.46 t/ha and from the 4th variant 12.34 t/ha. The decrease of mass in individual parts of plants were observed but their percentage portions were not affected by the level of weed infestation. A high dependence ( = 0.01) between the mass of the whole plant and the ear mass (r = 0.98) was proved. The total number of leaves was not affected by the level of treatment. The results show that the mechanical cultivation of stands at the beginning of vegetation cannot prevent the yield depression cost by weed infestation and the studied parameters cannot reach the level of fully weeded variants. Keywords: maize, weed infestation, chemical treatment, mechanical treatment, yield, morphological parameters Journal: Plant, Soil and Environment Pages: 371-378 Volume: 50 Issue: 8 Year: 2004 DOI: 10.17221/4046-PSE File-URL: http://pse.agriculturejournals.cz/doi/10.17221/4046-PSE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/pse-200408-0007.txt Handle: RePEc:caa:jnlpse:v:50:y:2004:i:8:id:4046-PSE Template-Type: ReDIF-Article 1.0 Author-Name: M. Rohošková Author-Workplace-Name: Czech University of Agriculture in Prague, Czech Republic Author-Name: M. Valla Author-Workplace-Name: Czech University of Agriculture in Prague, Czech Republic Title: Comparison of two methods for aggregate stability measurement - a review Abstract: Soil structure is a very important soil property, which influences many processes in the soil. There are many methods for aggregate stability measurement varying in the energy applied in the treatment. The aim of this paper is to compare two aggregate stability measurement methods on a set of reclaimed dumpsite soils. Method proposed by Le Bissonnias (1996) is composed of three tests, which allow distinguishing the particular aggregate breakdown mechanisms. Results can be expressed by a coefficient of vulnerability (Kv). Results of the second method, assessment of water stable aggregates, can be expressed by WSA index. WSA indexes mainly correspond to the results of the first test, which qualify the aggregate breakdown during the fast wetting. A strong statistically significant relationship was found between WSA and Kv for each test. Correlation coefficients were -0.767, -0.806, and -0.741 for linear models. Our conclusion is that results of both methods are comparable. Keywords: soil structure, aggregate stability, soil reclamation, soil analysis Journal: Plant, Soil and Environment Pages: 379-382 Volume: 50 Issue: 8 Year: 2004 DOI: 10.17221/4047-PSE File-URL: http://pse.agriculturejournals.cz/doi/10.17221/4047-PSE.html File-Format: text/html Handle: RePEc:caa:jnlpse:v:50:y:2004:i:8:id:4047-PSE