THE Ca, K and Mg RATIO IN SOIL AND VINES UNDER EFECTS OF FERTILIZATION WITH DIFFERENT POTASSIUM FERTILIZER DOSES

The investigation was carried out in the vineyards of “Radmilovac” on the Faculty of Agriculture experimental station, with cv. Sauvignon blanc grafted to the rootstock Berlandieri x Riparia Kober 5BB. The aim of this research was to determine the effects of potassium fertilizer application on the Ca:Mg and K:Mg ratio in soil and vines organs. In this experiment the following treatments were used: control (without fertilization) and treatments with 50, 100 and 150 kg K2O/ha 50% KCl potassium fertilizer. The soil type was eutric cambisol. Treated soil was subjected to the detail agrochemical soil analysis, while the soil samples was collected from the depth of 0-30, 30-60, 60-90 and 90-120 cm. Leaves for analysis were collected in august and shoots after pruning. Potassium and magnesium analysis has been by AAS. The level of available potassium was (11,95-14,15 mg/100g of soil), magnesium (20,2-23,7 mg/100 g of soil) and calcium (354-464 mg/100 g of soil). During the first year, Ca:Mg ratio was 5,8-14,4:1, in the second year 5,4-18,5:1 and at third year 4,9-25,2:1. The K:Mg ratio ranged from 0,08-0,21:1 in the first, 0,13-0,29:1 in the second and 0,11-0,21:1 in the third year of study. The Ca:Mg and K:Mg ratio were mostly influenced by 100 and 150 kg K2O/ha potassium doses. The K:Mg ratio in the leaves and shoots did not change under influence of different potassium fertilizer doses, so that the antagonism between these two elements was not manifested

Electronic Conductivity in Zinc Iron Phosphate Glasses

The electrical properties of (40−x)ZnO-xFe2O3-60P2O5 (x = 10, 20, 30 mol%) glasses were measured by impedance spectroscopy in the frequency from 0.01 Hz to 4 MHz and the temperature range from 303 to 473 K. It was shown that the dc conductivity strongly depends on the Fe2O3 content and Fe(II)/Fetot ratio. The increase in dc conductivity for these glasses is attributed to the increase in Fe2O3 content from 10 to 30 mol%. With increasing Fe(II) ion content from 6% to 17% the dc conductivity increases. This indicated that the conductivity arises mainly from polaron hopping between Fe(II) and Fe(III) ions suggesting an electron conduction in these glasses. By applying scaling on conductivity data measured at different temperatures, single master curve was obtained for each glass. On the other hand, deviation from the master curve at high frequencies was observed for glasses with different compositions. This deviation originates from a various mobility of charge carriers in different glass structures. Raman spectra showed the change of structure, from metaphosphate to pyrophosphate, with increasing Fe2O3 content from 10 to 30 mol%

Electronic Relaxation in Zinc Iron Phosphate Glasses

The electrical and dielectric properties of 10ZnO-30Fe2O3-60P2O5 (mol%) glasses, melted at different temperatures were measured by impedance spectroscopy in the frequency range from 0.01 Hz to 3 MHz and over the temperature range from 303 to 473 K. It was shown that the dc conductivity strongly depends on the Fe(II)/[Fe(II) + Fe(III)] ratio. With increasing Fe(II) ion content from 17% to 37% in these glasses, the dc conductivity increases. Procedure of scaling conductivity data measured at various temperatures into a single master curve is given. The conductivity of the present glasses is made of conduction and conduction-related polarization of the polaron hopping between Fe(II) and Fe(III), both governed by the same relaxation time, τ. The high frequency dispersion in electrical conductivity arises from the distribution in τ caused by the disordered glass structure. The evolution of the complex permittivity as a function of frequency and temperature was investigated. At low frequency the dispersion was investigated in terms of dielectric loss. The thermal activated relaxation mechanism dominates the observed relaxation behavior. The relationship between relaxation parameters and electrical conductivity indicates the electronic conductivity controlled by polaron hopping between iron ions

Correlation between the microstructure and the electrical properties of ZrTiO₄ ceramics

A series of ZrTiO4 (ZT) ceramics were prepared by sintering ball-milled precursor powders. Ceramics with homogenously dispersed micropores containing both low-temperature (ordered) and high-temperature (disordered) ZrTiO4 phases were achieved by sintering at 1400°C. The porosity and the morphology were modified by changing the sintering time. The impedance spectra followed the observed changes in the ceramics' microstructure. The grain boundaries' shape, rather than the grain size, has the major influence on the conductivity. The lowest value for electrical conductivity, 8.1 × 10−10 (Ω·m)−1, was obtained in the ceramics sintered at 1400°C for 4 h. This confirms the blocking effect of the imperfect grain boundaries; i.e., the defects of the grain boundaries, which were formed during the grain growth, were followed by an almost complete loss of pores

An outbreak of haemorrhagic fever with renal syndrome linked with mountain recreational activities in Zagreb, Croatia, 2017

Abstract In 2017 Zagreb faced the largest outbreak of haemorrhagic fever with renal syndrome (HFRS) to date. We investigated to describe the extent of the outbreak and identify risk factors for infection. We compared laboratory-confirmed cases of Hantavirus infection in Zagreb residents with the onset of illness after 1 January 2017, with individually matched controls from the same household or neighbourhood. We calculated adjusted matched odds ratios (amOR) using conditional logistic regression. During 2017, 104 cases were reported: 11–81 years old (median 37) and 71% (73) male. Compared with 104 controls, cases were more likely to report visiting Mount Medvednica (amOR 60, 95% CI 6–597), visiting a forest (amOR 46, 95% CI 4.7–450) and observing rodents (amOR 20, 95% CI 2.6–159). Seventy per cent of cases (73/104) had visited Mount Medvednica prior to infection. Among participants who had visited Mount Medvednica, cases were more likely to have drunk water from a spring (amOR 22, 95% CI 1.9–265), observed rodents (amOR 17, 95% CI 2–144), picked flowers (amOR 15, 95% CI 1.2–182) or cycled (amOR 14, 95% CI 1.6–135). Our study indicated that recreational activity around Mount Medvednica was associated with HFRS. We recommend enhanced surveillance of the recreational areas during an outbreak

Changes in soil carbon stock under the wheat-based cropping systems at Vojvodina province of Serbia

The aim of this study was to assess the changes in soil organic carbon (SOC) stock in relation to the carbon (C) input from nine wheat-based cropping systems and untilled grass. The SOC pool ranged from 32.1 to 49.4 Mg ha(-1) at 0-20 cm and from 94 to 171 Mg ha(-1) at 0-100 cm for the arable soil, while in untilled grassland, it was higher (54 and 185 Mg C ha(-1), respectively). SOC stock was observed to be lower at the unfertilized 2-year rotation and higher at the 4-year rotation with manure and mineral fertilization. The study showed a winter wheat yield decrease of 176.8 kg ha(-1) for a 1- Mg ha(-1) SOC stock change in the 0-20-cm soil depth. The estimated C input for SOC stock maintenance was from 266 to 340 g C m(-2) year(-1) for winter wheat and rotations, respectively. Additional C input did not increase the SOC pool, suggesting that arable plots had a limited ability to increase SOC. These results provide guidance for the selection of management practices to improve C sequestration

Impact of a severe flood on large-scale contamination of arable soils by potentially toxic elements (Serbia)

Extreme flooding in May, 2014 affected the sub-catchments of six major rivers in Serbia. The goal of the study was to evaluate the contents of potentially toxic elements (PTEs) As, Cd, Pb, Cr, Ni, Cu, and Zn in flood sediments and arable soils within the affected sub-catchments using regulatory guidelines and BACKGROUND: levels. The sub-catchment of West Morava was selected to assess the degree of sediments and soils contamination and environmental risk [using the Pollution index (P-i), Enrichment factor, Geo-accumulation index, and Potential ecological risk index (PERI)] as well as to identify main PTEs sources by Principal component (PCA) and cluster analysis. Contents of Ni, Cr, As, Pb, and Cu above both guidelines and BACKGROUND: levels, and of Zn and Cd above BACKGROUND: levels were detected in the sediments and soils from all the sub-catchments. P-i indicted that about 95% of the soils and sediments were extremely polluted by Ni and about 65% slightly polluted by Cr, whereas about 90% were not polluted by As, Cd, Pb, Cu, or Zn. E-f indicated minor to moderate enrichment of the soils and sediments by Ni, and Cr. PCA differentiated a geogenic origin of Ni, Cr, As, and Pb, a mixed origin of Cd and Zn, and a predominantly anthropogenic origin of Cu. PERI of the soils and sediments suggested a low overall multi-element ecological risk. The ecological risk of the individual elements (E) for soils was Zn lt Cr lt Pb lt Ni lt Cu lt As lt Cd