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Search Results: 1 - 10 of 190063 matches for " Mandi? Leka G. "
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Anthropogenic effects on soil micromycetes
?uki? Dragutin A.,MandiLeka G.,?umanov Vesna,Raketi? Svetlana
Zbornik Matice Srpske za Prirodne Nauke , 2007, DOI: 10.2298/zmspn0713179d
Abstract: This paper is a synthesis of long-term investigations based on the effect of different authropogenic pollutants (mineral and organic fertilizers, heavy metals, contaminated irrigation water, nitrification inhibitor and detergents) on the dynamics of soil fungi number. The investigations were performed at the Microbiology Department and trial fields of the Faculty of Agronomy in a ak on smonitza and alluvium soils in field and under greenhouse conditions. Maize, wheat, barley and red clover were used as test plants in these studies. The quantitative composition of the fungi in the soils investigated was determined by the apek selective agar dilution method. The study results show that the number of soil fungi was dependent on the type and rate of agrochemicals used, on the growing season, and the soil zone the samples were taken from for the analysis. Lower nitrogen fertiliser rates (80 and 120 kg x ha-1) and organic fertilizers stimulated the development of soil fungi, unlike the rate of 150 kg x ha-1. Heavy metals, mercury and cadmium in particular, as well as high rates of the N-serve nitrification inhibitor, inhibited the development of this group of soil microorganisms. Generally, the adverse effect of contaminated irrigation water on the soil fungi was recorded in both soil types, and particularly in the smonitza under red clover. Low detergent (Meril) concentrations did not have any significant effect on this group of microorganisms. In this respect, it can be concluded that the soil fungi number dynamics can be used in monitoring soils polluted by different toxinogenic substances.
The soil proteolytic activity and organic production of corn under the conditions of applying different nutrition systems
MandiLeka G.,?uki? Dragutin A.,Stevovi? Vladeta I.
Zbornik Matice Srpske za Prirodne Nauke , 2004, DOI: 10.2298/zmspn0417101m
Abstract: The effects of increasing amounts of mineral nitrogen (90, 120, 150 kg·ha-1) liquid (80 t·ha-1) and solid manure (45 t·ha-1) those of inoculation with Azotobacter chroococcum (the strain 84) on the soil proteolytic activity and corn yield grown in monoculture were surveyed over the 3-year-long research work. The research results indicated that proteolytic activity and corn yield depended highly on the fertiliser sorts, amounts and on the research year too. Over the first research year, the highest proteolytic activity was recorded on the variants with organic fertilisers, whereas the fertiliser stimulating effect markedly decreased, particularly with liquid manure over the following two years of the research. Mineral fertilisers were also found to remarkably stimulate the biological parameters we have been concerned above, particularly the mean N amount (120 kg · ha-1). While the highest corn yield could be obtained using 120 kg N · ha-1 throughout all the research years, its insignificant rise and barely altered soil proteolytic activity using corn seed inoculation with 84 Azotobacter chroococcum could be noticed.
The influence of mineral and bacterial fertilization on the number of fungi in soil under maize
Stanojkovi? Aleksandra B.,?uki? Dragutin A.,MandiLeka G.,Mili?i? Bogi? M.
Zbornik Matice Srpske za Prirodne Nauke , 2011, DOI: 10.2298/zmspn1120205s
Abstract: The aim of this study was to evaluate the influence of an application of different rates of mineral fertilizers and their combination with associative N-fixing Klebsiella planticola and Enterobacter spp., and sampling period on the number of fungi in Cambisol and grain yield of maize. The investigation was conducted on Mladenovac experimental station and in the Laboratory of Institute of Soil Science, Belgrade, during 2006. Unfertilized soil was used as the control soil. Each of the studied variants was carried out in three replications. The effect of the studied fertilizers was determined three times during the maize growing season, the number of fungi being determined by indirect dilution method on Czapek nutritive medium. The results of the study showed that all fertilization variants studied influenced, more or less, fungal growth in the study soil. However, the applied high content of mineral nitrogen, phosphorus and potassium, as well as their combination with bacterial inoculants brought about the highest increase in the number of fungi during all studied vegetation periods of maize. The highest increase in the number of soil fungi was registered in the second sampling period. The highest increase in the grain yield of maize was obtained by combined application of microbial inoculants and high rates of mineral NPK fertilizers.
Potentially pathogenic, pathogenic, and allergenic moulds in the urban soils
?uki? Dragutin A.,MandiLeka G.,Bo?ari? Lidija,Trifunovi? Bojana D.
Zbornik Matice Srpske za Prirodne Nauke , 2011, DOI: 10.2298/zmspn1121125d
Abstract: The dynamics of soil mould populations that can compromise the human immune system was evaluated in experimental plots located at different distances (100, 300, 500, 700 and 900 m) from the main source of pollution - the Podgorica Aluminum Plant. Soil samples were collected in July and October 2008 from three different plot zones at a depth of 0-10 cm. The count of potentially pathogenic, keratinolytic and allergenic (melaninogenic) moulds was assessed, which can significantly contribute to both diagnosis and prophylaxis. The count of medically important moulds was higher in the urban soil than in the unpolluted (control) soil. Their count decreased with increasing distance from the main pollution source (PAP). Their abundance in the soil was considerably higher in autumn than in spring.
Mineral fertilizers as a governing factor of the regulation of the number of fungi in soil
Pe?akovi? Marijana I.,?uki? Dragutin A.,MandiLeka G.,Raki?evi? Milan L.
Zbornik Matice Srpske za Prirodne Nauke , 2009, DOI: 10.2298/zmspn0916201p
Abstract: Over 2003-2005 period, a study was performed on the effect of different rates of NPK fertilizer of formulation 8:16:24 + 3% MgO (N1 - 400 kg ha-1; N2 - 600 kg ha-1; N3 - 800 kg ha-1; N4 - 1000 kg ha-1) on development of the soil fungi. The trial was set up in the experimental plum orchard established by Fruit Research Institute a ak, and the laboratory of Department of Microbiology, Faculty of Agronomy a ak. Unfertilized soil was used as the control soil. Each of the stated variants was carried out in three replications. The size of the basic plot was 68 m2. The effect of the studied mineral fertilizer rates was determined three times over the growing season, the number of fungi being checked by the indirect rarefaction method on Chapek nutritive medium. The results of the study inferred that the application of mineral fertilizers brought about the decrease in the number of fungi. Of all studied variants, the one with the highest nitrogen rate (variant N4) exhibited the strongest effect. The influence of the fertilizer was highest at the third sampling. Furthermore, the effect was highest in season 2003.
Microbial Characteristics of Vertisol Under Different Fertilization Systems
Leka MANDI,Dragutin DJUKI?,Marijana Pesaokvi?
Journal of Central European Agriculture , 2012, DOI: 10.5513/jcea01/13.1.1005
Abstract: The present study evaluates the effect of increasing rates of mineral nitrogen (90; 120; 150 kg×ha-1), liquid manure (80 t×ha-1) and solid manure (45 t×ha-1) on the microbial properties of vertisol (total number of microorganisms, numbers of actinomycetes and cellulolytic microorganisms) under maize. The research results showed dependence of the number of the test groups of microorganisms on the type and rate of fertilization, as well as on the date and zone of sampling. Namely, lower nitrogen fertilization rates (90 and 120 kg×ha-1) induced a significant increase in the total number of microorganisms, whereas the high rate (150 kg×ha-1) had a depressive effect, especially in maize edaphosphere. However, the numbers of actinomycetes and cellulolytic microorganisms were not reduced under these treatments. The organic fertilizers applied had a stimulatory effect on the above soil biological parameters.
Soil fungi as indicators of pesticide soil pollution
MandiLeka,?uki? Dragutin,?or?evi? Sne?ana
Zbornik Matice Srpske za Prirodne Nauke , 2005, DOI: 10.2298/zmspn0519097l
Abstract: Soil fungi, with their pronounced enzymic activity and high osmotic potential, represent a significant indicator of negative effects of different pesticides on the agroecosystem as a whole. In that respect, a trial was set up on the alluvium soil type with the aim to investigate the effect of different herbicides (Simazine, Napropamid, Paraquat), fungicides (Captan and Mancozeb) and insecticides (Fenitrothion and Dimethoate) on a number of soil fungi under apple trees. The number of soil fungi was determined during four growing seasons by an indirect method of dilution addition on the Czapek agar. The study results indicate that the fungi belong to the group of microorganisms that, after an initial sensible response to the presence of pesticides in the soil, very rapidly establish normal metabolism enabling them even to increase their number. The fungicides and insecticides applied were found to be particularly effective in that respect.
EFFECT OF NPK FERTILIZER ON THE GROWTH OF SAPROPHYTIC FUNGI IN ALLUVIAL SOIL
Marijana PE?AKOVI?,Dragutin ?UKI?,Leka MANDI,Rade MILETI?
Journal of Central European Agriculture , 2010,
Abstract: The influence of different NPK fertilizer rates on the developement of the saprophytic fungi of the alluvial soil planted with plum culture has been studied over the three-year period (2003 – 2005). The trial was set up in the experimental plum orchard established by Fruit Research Institute a ak (Serbia) and at the laboratory of Department of Microbiology, Faculty of Agronomy a ak (Serbia). The soil was treated with 8:16:24 + 3% of MgO mineral fertilizer in the following treatment variants: variant N1 – 400 kgha-1; variant N2 – 600 kgha-1; variant N3 – 800 kgha-1 and variant N4 –1000 kgha-1, all treatment variants being applied in three replications. Unfertilized soil served as the control. The size of the trial plot was 68 m2. The effect of the studied mineral fertilizer rates was determined three times over the growing season. It was checked by identification of the number of saprophytic fungi by the indirect rarefaction method on Czapek nutritive medium. The results of the study suggested that the number of the saprophytic fungi varied by different fertilizer rates, periods of sampling and years of study. The application of fertilizers brought about increase in the number of the saprophytic fungi. Of all studied treatment variants, the one with highest nitrogen rate (variant N4) exhibited the strongest effect. The influence of the applied fertilizer was highest over the third sampling period. Furthermore, the effect thereof was highest in 2003. The application of 600 kgha-1 of mineral fertilizer resulted in the highest plum yield.
Modelling and Interpreting The Effects of Spatial Resolution on Solar Magnetic Field Maps
KD Leka,G. Barnes
Physics , 2011, DOI: 10.1007/s11207-011-9821-7
Abstract: Different methods for simulating the effects of spatial resolution on magnetic field maps are compared, including those commonly used for inter-instrument comparisons. The investigation first uses synthetic data, and the results are confirmed with {\it Hinode}/SpectroPolarimeter data. Four methods are examined, one which manipulates the Stokes spectra to simulate spatial-resolution degradation, and three "post-facto" methods where the magnetic field maps are manipulated directly. Throughout, statistical comparisons of the degraded maps with the originals serve to quantify the outcomes. Overall, we find that areas with inferred magnetic fill fractions close to unity may be insensitive to optical spatial resolution; areas of sub-unity fill fractions are very sensitive. Trends with worsening spatial resolution can include increased average field strength, lower total flux, and a field vector oriented closer to the line of sight. Further-derived quantities such as vertical current density show variations even in areas of high average magnetic fill-fraction. In short, unresolved maps fail to represent the distribution of the underlying unresolved fields, and the "post-facto" methods generally do not reproduce the effects of a smaller telescope aperture. It is argued that selecting a method in order to reconcile disparate spatial resolution effects should depend on the goal, as one method may better preserve the field distribution, while another can reproduce spatial resolution degradation. The results presented should help direct future inter-instrument comparisons.
Creating conditions for cooperative learning: Basic elements
?evku?i?-Mandi? Slavica G.
Zbornik Instituta za Pedago?ka Istra?ivanja , 2003, DOI: 10.2298/zipi0335094s
Abstract: Although a large number of research evidence speak out in favor of cooperative learning, its effectiveness in teaching does not depend only on teacher’s and students’ enthusiasm and willingness to work in such a manner. Creating cooperative situations in learning demands a serious preparation and engagement on the part of teacher who is structuring various aspects of work in the classroom. Although there exist a large number of models and techniques of cooperative learning, which vary in the way in which students work together, in the structure of learning tasks as well as in the degree to which cooperative efforts of students are coupled with competition among groups, some elements should be present in the structure of conditions irrespective of the type of group work in question. Potential effects of cooperation are not likely to emerge unless teachers apply five basic elements of cooperative structure: 1. structuring of the learning task and students’ positive interdependence, 2. individual responsibility, 3. upgrading of "face to face" interaction, 4. training of students’ social skills, and 5. evaluation of group processes. The paper discusses various strategies for establishing the mentioned elements and concrete examples for teaching practice are provided, which should be of assistance to teachers for as much successful cooperative learning application as possible in work with children.
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