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Agriculture, as one of the most important branches of economy, depends on climate conditions and has a significant contribution to climatic changes process, primarily by releasing greenhouse gases (GHG). It is estimated that agriculture directly emits about 9% of the total amount of GHG, of which 5% originates from soil and about 4% from livestock production (ruminants). Emissions of carbon dioxide into the atmosphere from cultivated soil are 27% to 90% higher compared to natural grasslands. For greater climate neutrality of agriculture, two-way action is necessary: towards the reduction of GHG and towards the sequestration of carbon in the soil. Recommended measures and practices in the management of organic carbon content in soil include a wide range of agronomic, biological, technical and technological procedures, management and structural practices on agricultural soil. By encouraging organic plant production, which should contribute to maintaining and increasing the natural fertility of the soil, as well as preserving and improving biodiversity and stabilizing the structure of the soil, it can contribute to mitigating climate change.

Simple Summary The study evaluated the effects of the application of microbial inoculants (N-fixing Klebsiella planticola and Enterobacter spp.), two rates of composite mineral fertilizers, and their combination on microbial biomass carbon, dehydrogenase and proteinase activity in acid Lessivated Cambisol and yield-related properties of maize and wheat grains in a two-year trial. The results indicated that mineral fertilizers are not, in general, negative for soil microbiota when used in the context of sustainable agriculture without monoculture. It was found that the combined application of microbial inoculants and lower doses of mineral nitrogen, phosphorus, and potassium (NPK) fertilizers, increased the yield of maize and wheat compared to the use of only NPK fertilizers in our case study. The highest values of the examined parameters of soil fertility were determined in the period with better precipitation distribution during the vegetation period of the studied year due to the optimal values of soil moisture and air temperature. Concluding, the authors point out the task of science to offer the producer a solution for conducting intensive agricultural production, which must be economically and ecologically safer. Abstract This study evaluated the effects of the application of microbial inoculants (N-fixing Klebsiella planticola and Enterobacter spp.), two rates of composite mineral fertilizers, and their combination on microbial biomass carbon (MBC), dehydrogenase (DHA), and proteinase activity (PTA) in Lessivated Cambisol and yield-related properties of maize and wheat grains in a two-year trial. Unfertilized soil was used as a control variant. MBC was measured using the chloroform fumigation-extraction method, DHA was determined spectrophotometrically by measuring the intensity of the formed red-colored triphenyl formazan, while PTA was determined using a titration method by measuring the degree of gelatine decomposition. In grain samples, P was determined spectrophotometrically, K—by flame emission photometry, N—on an elemental carbon/nitrogen/sulfur (CNS) analyzer, and crude proteins—by calculation of N content. Measuring both crops’ yield was carried out at the end of the vegetation. The results indicated that mineral fertilizers are not, in general, negative for soil microbiota when used in the context of sustainable agriculture without monoculture. There is a significant increase in the values of soil MBC, DHA, and PTA in the variants with combined application of bacterial inoculants and lower rates of mineral fertilizers. The highest values of these parameters were determined in the period with a better distribution of precipitation during the vegetation period of the year. The mentioned combination also resulted in a higher grain yield of maize and wheat comparing to the application of lower rates of the NPK nutrients solely. The combined application of high rates of mineral fertilizers and bacterial inoculants resulted in significantly increased N, P, K, and protein content in the grains of crops, and the same applied to yield. Concluding, studied bacterial inoculants can be used to specify the replacement of nitrogen fertilizers, stimulating the microbial biomass and enzyme activity in the soil, helping to ensure that the supply of nutrients contributing to an optimized yield of crops is maintained.

Summary Pseudomonas sp. and Bacillus sp. belong to plant growth promoting rhizobacteria which are able to colonize the plants roots and stimulate growth. In this study, the effect of two indigenous plant growth promoting rhizobacterial strains Pseudomonas sp. Q4 and Bacillus sp. Q10 and their mixture (mix Q4+Q10) on content of the main chemical growth parameters (nitrogen, phosphorus, potassium, calcium and magnesium) and the yield of dry biomass of radicchio (Cichorium spp. var. rossa di treviso) aerial parts and root, was investigated. The study was carried out with stagnosol type of soil in pot experiments under semi-controlled conditions in the Institute of Soil Science (Belgrade), in the period from July to October in 2013. Phosphorus was determined by spectrophotometer, potassium - by flame emission photometry and total nitrogen and carbon - using elemental CNS analyzer, while calcium and magnesium were determined by AAS. The data on yield of both aerial parts and root dry biomass of radicchio showed that its treatment with Q4 and Q10 strains, as well as with their mixture, caused noticeably increase in this parameter in relation to the control, whereby the strain Q4 was more effective for aerial parts, while mix Q4+Q10 - for roots. The obtained data on the studied chemical parameters of radicchio root and aerial parts were in total accordance with their yield. Concluding, studied strains have a potential in promoting the biomass yield and main chemical growth parameters of both aerial parts and root of radicchio.

The effects of plant growth promoting (PGP) bacteria on soybean growth and yield were tested in field conditions using four treatments: (A) Bradyrhizobium japonicum strain 526, combined with cell-free supernatants (CFS) of Bacillus sp. strain Q10 and Pseudomonas chlororaphis strain Q16; (B) B. japonicum 526 + Bacillus sp. Q10; (C) B. japonicum 526 + P. chlororaphis Q16 and (D) commercial fertilizer containing B. japonicum , which served as a control. The average values of dry weight per nodule and shoot dry weight had the maximum values in the B treatment. In dry shoots collected at the flowering stage, nitrogen and carbon content was similar across all treatments, while that of sulphur decreased in treatment A. Relative to the control (D), all treatments showed positive effects on pods number and grain mass per plant, with the best results yielded by treatment A. Nitrogen and sulphur content in grain were significantly higher in treatment C, whereas maximum carbon content was measured in treatment B. In the control, it was obtained the yield of 4,000 kgha -1 , which was in accordance with data reported by the seed producer for the same growing conditions (the maximum value). The yields of 4,229, as well as 4,286 and 4,400 kg ha -1 were measured for variants C, B and A, respectively, which were statistically significant higher (5.73 to 10%) than the commercial fertilizer (D). The improvement in soybean growth and yield in the field trial achieved by addition of PGP strains Bacillus sp. Q10 and P. chlororaphis Q16 to B. japonicum 526 can result in more productive agricultural practices.

The bioavailability of trace elements (TEs) is one of the major factors for successful plant production and environmental protection. The aim of this study was to determine the extent to which TEs are bioavailable and which of the basic soil parameters affect bioavailability. The survey included agricultural soil samples taken from 240 locations on the territory of the Republic of Serbia, where the soil analytics were carried out. On the basis of the analyzed data the prediction models were derived based on the Freundlich model, showing the dependence between trace elements (TEs) extracted using the DTPA buffer solution in relation to the trace elements extracted using an aqua regia, the organic matter content (SOM), the clay fractions content, and soil pH. On one part of the samples, the prediction models were separated on the basis of a suspension for determining the pH in H2O and 1M KCl. The model was applied for the following TEs: Mn, Ni, Pb, Zn, and Cu. The content of the pseudo total forms of TEs statistically significantly influenced the bioavailability of TEs in all prediction models for all studied elements. The pH value statistically significantly affected the bioavailability of Ni, Mn, Pb, and Cu also in all prediction models. The impact of SOM and clay varied depending on the model and TEs. Multiple linear regression showed that the prediction models for TE Cu (R2 = 0.763&ndash, 0.848) were the most reliable and that the bioavailability of Cu was significantly influenced by all the studied soil parameters except clay. Reliable results were also shown by the prediction models for TE Pb, but the values of the determination coefficient and investigated parameters that influenced the bioavailability varied depending on the model. The derived models for TE Mn, Zn, and Ni were less reliable (R2 is approximately 50% or less), and the effect of the tested parameters on bioavailability varied depending on the model and TEs.

The assessment of the weed infestation effect on biomass yield of Miscanthus x giganteus in the first year of its commercial yield was conducted on two types of soil with different productive ability Luvic Chernozem and Calcic Gleysol. The formed mass of weeds was higher on Luvic Chernozem and the infestation had grown according to the stages of Miscanthus growth. The biomass of weeds depended on the planting density of Miscanthus as well as on the weather conditions during the studied years. Weed infestation of crops very significantly influenced the formation of aboveground biomass of Miscanthus, so that the yields in the first year of commercial harvesting in the control where the weeds were removed manually were significantly higher compared to the crops in which weeds were not removed. The obtained results showed that weeds significantly affect the initial growth and development of Miscanthus plants that are, in general, slow, especially in the year of the crop establishment. The study evaluates the impact of a manual method of suppression and weed infestation of crops on the commercial yield of Miscanthus.

Campylobacteriosis is an infectious human disease caused by thermophilic Campylobacter species, mainly C. jejuni and C. coli. It is the leading cause of human gastroenteritis today with the number of cases surpassing the number of Salmonella poisoning cases. The epidemiology of the agent is not completely clear, but a number of investigations indicate an important role of broiler meat in human infections. The purpose of this study was to investigate the diversity of Campylobacter jejuni strains present in the Republic of Serbia and to determine a fast and reliable system for the confirmation and typing of the isolated strains. Samples taken at slaughterhouses, broiler farms, as well as two human isolates of Campylobacter species have been investigated. Strain identification was performed by multiplex-PCR. Genotyping was performed by Random Amplified Polymorphic DNA (RAPD) with multiple primers. Using several unusual primers and a newly designed one (DJP17), we report on the RAPD types of indigenous Campylobacter species. RAPD profiles showed different levels of discrimination between the isolates, depending on the primer: SPH1 and AG15 were informative only in part and better results were obtained with AP10, AK16 and DJP17.

The aim of this study was to detect genes for enterotoxins (hbla, entFM and bceT) and for emetic toxin (cer), to determine antibiotic resistance, and to estimate intraspecies diversity in B. cereus isolates by RAPD analysis. B. cereus was identified in 12 out of 117 indigenous Bacillus spp. using the classical microbiological methods and PCR. All isolates were resistant to penicillin and ampicillin, two to tetracyclin and four to trimethoprim-sulphamethoxazole. Also, all isolates produced inducible penicillinases and β-lactamase. Toxin genes were detected with PCR. EntFM and cer genes were present in all isolates, hbla in all, but two, and bceT in none. RAPD analysis was performed with four different primers, two of them designed for this study. The intraspecies diversity revealed 10 different patterns at the 90% similarity level. Two separate clusters were formed regardless of a soil type or utilization. The detection of genes encoding toxins in all B. cereus isolates indicated these bacteria as potentially pathogenic and seriously for human health. Regardless of a soil type or utilization, the RAPD analysis showed high intraspecies heterogeneity in B. cereus isolates. To the best of our knowledge, this is the first study to analyse the presence of entero- and emetic toxin genes and genetic heterogeneity in B. cereus isolates from different soil types and different soil utilization in Serbia. [Projekat Ministarstva nauke Republike Srbije, br. TR37006]

Water table forecasting plays an important role in the management of groundwater resources in agricultural regions where there are drainage systems in river valleys. The results presented in this paper pertain to an area along the left bank of the Danube River, in the Province of Vojvodina, which is the northern part of Serbia. Two soft computing techniques were used in this research: an adaptive neurofuzzy inference system (ANFIS) and an artificial neural network (ANN) model for one-month water table forecasts at several wells located at different distances from the river. The results suggest that both these techniques represent useful tools for modeling hydrological processes in agriculture, with similar computing and memory capabilities, such that they constitute an exceptionally good numerical framework for generating high-quality models.

The effect of metallurgical slag application on chemical properties of the soils with limited productive ability (Stagnosol), as well as on chemical composition of cultivated vegetables (spinach and cabbage) as experimental crops, through the vegetative experiments performed in semi-controlled conditions, was studied. The longterm investigations were aimed to define the main parameters for possible wider usage of this secondary raw material (by-product of the steel industry, respectively) for chemical melioration and fertilization of acid soils in Serbia, as well as to indicate the justification of its application in agricultural practice. Generally, it was concluded that the studied metallurgical slag of the standardized chemical composition can be added to the acid soils toward amelioration the fertility without adverse effects.

This study examined the effect of two indigenous plant growth promoting rhizobacterial strains of P. chlororaphis (Q16 and B25) on morphological (plant height; root length; number of leaves, buds and lateral branches) and main chemical (contents of N, P, K, Ca, Mg) growth parameters of two basil cultivars (Italiano classico and SRX 1920). The experiment was conducted in pots under glasshouse conditions from March to July 2014. Phosphorus was determined by spectrophotometer, potassium by flame emission photometry, nitrogen by using elemental CNS analyzer Vario EL III, while calcium and magnesium were determined by AAS. The obtained results showed that the treatment of basil cultivars with both P. chlororaphis strains had positive effect on all studied growth basil parameters in relation to the control, whereby the strain B25 was more effective than Q16. Concluding, tested P. chlororaphis strains have high potential in promoting the morphological and main chemical growth parameters of basil.

The contents of heavy metals and trace elements and their accumulation in Medicago sativa L., cultivated on Eutric cambisol along the E75 route section Belgrade-Leskovac, were examined in order to assess the health and safety of animal feed. The samples of soil and aerial parts of the plant material were collected from both sides of lanes at 10, 30, 50 and 400 m perpendicular to the direction of the highway. Soil and plant analyses of the metals content were done according to ICP methodology. The results showed that at the locality L 14, a distance of 30 and 50 meters away from the lanes, the content of total forms of Cr, Ni and Pb in soil was above the maximum permissible concentration. In the plant biomass it was determined the following: in a sample from the location L 14 at a distance of 50 meters from the lanes concentrations of Ni and Co were higher than normal values, and concentrations of Fe and Pb were above toxic levels or maximum tolerance levels for animal feed; determined Fe content in the sample of alfalfa at location L 11, 400 m away from the lanes, and Ni in the sample from the site D 12 at a distance of 50 m from the lanes, was above the normal values, while in the sample from D12 location, at a distance of 30 m from the lanes, the content of Pb was above the toxic levels or maximum tolerance levels for animal feed. The results suggest a caution in the use of alfalfa, grown near the highway route, for animal feed because of the potential entry of heavy metals into the food chain. U deset uzoraka zemljišnog i biljnog materijala duž trase autoputa E 75 kroz Republiku Srbiju, na deonici od Beograda do Leskovca, ispitan je sadržaj teških metala i mikroelemenata i njihova akumulacija u Medicago sativa L. gajenoj na eutričnom kambisolu, radi ocene zdravstvene ispravnosti stočne hrane. Uzorci zemljišta i nadzemnog dela biljnog materijala uzorkovani su sa obe strane kolovoznih traka i to na 10, 30, 50 i 400 m upravno na pravac autoputa. Analiza zemljišnih uzoraka pokazala je da je na lokalitetu L 14, na udaljenosti 30 i 50 metara od kolovoznih traka sadržaj ukupnih formi Cr, Ni i Pb bio iznad maksimalno dozvoljenih koncentracija. U biljnoj masi u uzorku sa lokacije L14 na udaljenosti 50 metara od kolovoznih traka koncentracije Ni i Co su bile više od normalnih vrednosti, a koncentracije Fe i Pb bile su iznad toksičnih vrednosti odnosno maksimalno tolerantnog nivoa za ishranu životinja. Utvrđeni sadržaj Fe u uzorku lucerke na lokaciji L11 udaljenoj 400 m od kolovoznih traka, kao i Ni u uzorku sa lokacije D12 na udaljenosti 50 m od kolovoznih traka, bio je iznad normalnih vrednosti, dok je u uzorku D12 na udaljenosti 30 m od kolovoznih traka sadržaj Pb, bio iznad toksičnih vrednosti, odnosno maksimalno tolerantnih nivoa za ishranu životinja. Dobijeni rezultati upućuju na oprez pri korišćenju lucerke gajene pored trase autoputa za ishranu životinja zbog mogućeg ulaska teških metala u lanac ishrane.

Indoleacetic acid (IAA) producing Pseudomonas isolates from the rhizosphere of maize (Q4 and Q20), alfalfa (Q1 and Q16) and wild red clover (B25) were selected for the investigation of their effect on the biological vitality of the potato seed tubers. The production of IAA ranged from 4.09 to 15.9 µ gmL- 1 after 24h of cultivation and 4.08 to 26.4 µ gmL-1 after 48h of cultivation. The molecular comparison by RAPD analysis also was done. RAPD patterns of selected Pseudomonas spp. isolates obtained by BC318, AF14, SPH 1 and AP 10 primers demonstrated the suitability of RAPD method in distinguishing a high variability among the four isolates (44 to 68%). The effect on the biological viability of potato (industrially important variety Pirol) was observed during the seven weeks of sprouting at the temperature of 18-20°C. Potato tubers treated by the selected isolates formed slightly lower number of sprouts, but statistically higher mean length - up to 129.9% higher than the control. The mean sprouting capacity was 64.5% higher than a control. Obtained results suggested positive effects of selected IAA producing Pseudomonas isolates on the length of potato tubers and sprouting capacity as the parameters which define biological viability. [Projekat Ministarstva nauke Republike Srbije, br. III46007]

In 2006, the influence of different rates of applied mineral fertilizers and their combinations with bacterial inoculants [nitrogen (N)–fixing Klebsiella planticola and Enterobacter spp.] on the number of microorganisms from the N cycle in a Cambisol and the yield of maize was evaluated in this study. The results obtained implied that high rates of mineral fertilizers brought about an increase in the number of fungi and a decrease in the number of Azotobacter spp., oligonitrophiles, ammonifiers, and nitrifiers in soil. Combined application of microbial inoculants and low rates of mineral fertilizers resulted in the greatest increase in the number of Azotobacter spp., oligonitrophiles, and ammonifiers in soil. The greatest number of soil nitrifiers, as well as the grain yield of maize studied, were determined in the variants where combinations of the microbial inoculants and low and high rates of mineral fertilizers were applied.

The paper evaluates the competitive ability of Rhizobium leguminosarum bv trifolii strain T49B1 used as inoculant for Trifolium repens L. (Viola) and indigenous population of rhizobia from chernozem, stagnosol and humic gleysol. Nodule bacteria were identified using calcofluor effects (CF) based on succinoglycan production, and confirmed by IAR patterns and RAPD fingerprinting (using SPH1 primer). T49B1 nodules occupancy level from 71.78% in pseudoglay to 89.56% in chernozem was detected. Inoculation by T49B1 strain showed it to be a very good competitor with the possibility to establish effective symbiosis and increase protein content compared to non-inoculated (control) plants.

Antibiotic production by plant-associated microorganisms represents an environmentally compatible method of disease control in agriculture. However, a vide application of bacterial strains needs careful selection and genetic characterization. In this investigation, selected Pseudomonas strains were characterized by rep-PCR methods using ERIC and (GTG)5 primers, and partial 16S rDNA sequence analysis. None of strains produced homoserine lactones (C4, C6, C8) as quorum sensing signal molecules. Very poor production of phenazines and no significant fungal inhibition was observed for PS4 and PS6 strains. High amount of phenazines were produced by Pseudomonas sp. strain PS2, which inhibited mycelial growth of 10 phytopatogenic fungi in percent of 25 (Verticillium sp.) to 65 (Fusarium equiseti). Genetic characterization of the Pseudomonas sp. PS2 and evaluation of phenazines production, as the main trait for growth inhibition of phytopathogenic fungi, will allow its application as a biosafe PGPR for field experiments of plant disease control. Ekološki prihvatljiv metod kontrole bolesti bilja u poljoprivredi obuhvata primenu rizosfernih mikroorganizama koji produkuju antibiotike. Široka primena bakterija zahteva njihovu pažljivu selekciju i genetičku karakterizaciju. Ova istraživanja obuhvatila su karakterizaciju selektovanih Pseudomonas sojeva na osnovu rep-PCR metode korišćenjem ERIC i (GTG)5 prajmera, kao i parcijalne sekvence 16S rDNA. Nije detektovana produkcija acil-homoserin laktona (C4, C6, C8) kao QS molekula. Sojevi PS4 i PS6 su vrlo oskudno produkovali fenazine i nisu značajno inhibirali rast fitopatogenih gljiva. Soj Pseudomonas sp. PS2 je obilno produkovao 2-OH-PCA i PCA i inhibirao rast micelija 10 fitopatogenih gljiva od 25% (Verticillium sp.) do 65% (Fusarium equiseti). Genetička karakterizacija soja Pseudomonas sp. PS2 i detekcija produkcije fenazina kao glavnog inhibitora rasta fitopatogenih gljiva omogućiće primenu ovog soja kao bezbednog PGP agensa za biološku kontrolu u budućim ogledima u polju.

In Republic of Serbia the pseudogley type of soil outspreads on approximately 443.000 ha or 4,7 % of the total area. At the area of West and North-West Serbia this type of soil outspreads on approximately 360.000 ha or 20% of the total area. The main characteristics of Pseudogley are unfavorable chemical properties, heavy mechanical composition, compaction and low hydraulic conductivity, which result in an unregulated water-air regime. An ameliorative action that could regulate unfavorable water regime of these soil types is the implementation of the horizontal pipe drainage. On experimental drainage field Varna near Sabac, owned by Institute of Soil Science, on the pseudogley type of soil, it was established an experiment in order to follow the effect of different spaces of the horizontal pipe drainage on increase of the yields of main crops (wheat and maize) in relation to the undrained areas. The processing of data of the realized yields in the period 2004-2009 shows that on the plots on which the pipe drainage was implemented, compared to the undrained areas, the yield of wheat increased 8-60%, while the yield maize increased 6-43%. Regarding the areas at which this type of soil outspreads, by implementation of the complex amelioration measures this potentially productive soil would enable economically profitable agricultural production, especially crops for animal food. This will increase the opportunity for intensifying animal production.

According to scientific community and professional specialists, urging necessity to increase capacity of sources of energy can be partially achieved by using biomass as a raw material. This approach is justified by both economic and ecological reasons. In this paper the results of chemical study of the biomass Miscanthus × giganteus Greef et Deu. cultivated in the Republic of Serbia in the experimental field of the Institute for Application of Nuclear Energy in Zemun were presented. Study of an amount of ashes, elemental analysis of the biomass, and calorific value of the biomass (both higher and lower), which are critical parameters when estimating the quality of a biofuel, points out the possibility of utilization of the miscantus biomass as a fuel. Samples of the plant material for this study were collected during two harvesting periods: in the fall, when the biological yield is the highest, and at the end of the winter, when a highest quality biomass with respect to the combustion is obtained do to a decrease in moisture content and remobilization of the macro- and micronutrients from the above-ground parts of the plants to the rhizomes. Values of the studied parameters indicate that biomass meets the 'green' energy requirements because the amounts of oxides of nitrogen and sulphur in the combustion products would not threaten current quality of the environment and the amount of carbon dioxide produced would be consumed in the process of photosynthesis. Results of the chemical analyses strongly suggest to a high potential of utilization of the miscantus biomass as a biofuel (renewable source of energy) to generate thermal energy. Delimičan odgovor stručne i naučne javnosti na pitanje kako povećati kapacitete energetskih izvora je upotreba biomase kao sirovine, kako iz ekonomskih, tako i iz ekoloških razloga. U ovom radu su prikazani rezultati fizičko-hemijskih ispitivanja biomase miskantusa (Miscanthus × giganteus Greef et Deu.), gajenog na teritoriji Republike Srbije, oglednom polju Instituta za primenu nuklearne energije, Zemun. Ispitivanjem količine pepela, elementarnog sastava biomase i kalorične vrednosti biomase (donje i gornje), koji su presudni za procenu kvaliteta biogoriva, ukazano je na mogućnost eksploatacije biomase miskantusa kao biogoriva. Prikupljanje uzoraka biljnog materijala za ovo istraživanje izvršeno je u dva žetvena roka: u jesen - vreme maksimuma biološkog prinosa i krajem zime, kada se dobija kvalitetnija biomasa za sagorevanje usled smanjenja sadržaja vlage i remobilizacije makro- i mikrohraniva iz nadzemnih delova rizoma. Vrednosti ispitivanih parametara pokazuju da biomasa ispunjava zahteve 'zelene' energije, jer produkti sagorevanja biomase svojom količinom (oksidi N i S) ne bi ugrožavali postojeći kvalitet životne sredine, a količina nastalog ugljenik (IV) - oksida ne bi predstavljala ekološki problem, jer bi se dalje uključila u proces fotosinteze. Rezultati hemijskih analiza argumentovano ukazuju na veliki potencijal upotrebe biomase miskantusa kao biogoriva (obnovljivog izvora energije) u proizvodnji toplotne energije.

The purpose of the study was to evaluate the influence of an application of different rates of composite mineral fertilizers and their combination with bacterial inoculants (N-fixing Klebsiella planticola and Enterobacter spp.) on chemical composition and yield of the maize green biomass (without spikes) on acid Eutric Cambisol during the two growing seasons: 2006 and 2008. Unfertilized soil was used as a control. The contents of nitrogen, phosphorus, potassium and crude proteins in biomass samples were determined three times during the maize vegetation season, as follows: stage of intensive growth, milk-waxy maturity stage and full maturity stage. Measuring of the green biomass yield was carried out at the end of the vegetation. The results of the study showed that the use of high rates of composite mineral fertilizers and their combination with bacterial inoculants resulted in increased contents of nitrogen, phosphorus, potassium and crude proteins in the maize biomass during the both study years, which was noticeably observed in the stage of intensive growth. The highest increase in the biomass yield was obtained by the same mentioned treatments, although the combination of bacterial inoculants and lower rates of mineral fertilizers resulted in higher yields comparing to the application of lower rates of the pure mineral nutrients. The data suggest that the studied bacterial inoculants can be used in further investigations as the potential agents of new biofertilizers for improved maize production and other agriculture crops in animal nutrition. Cilj ovog istraživanja je bio da se proceni uticaj primene različitih doza kompleksnih mineralnih đubriva i njihovih kombinacija sa bakterijskim inokulantima (azotofiksirajuće bakterije Klebsiella planticola i Enterobacter spp.) na hemijski sastav i prinos zelene biomase kukuruza na kiselom eutričnom kambisolu tokom dve vegetacione sezone: 2006 i 2008. Neđubreno zemljište je služilo kao kontrola. Sadržaj azota, fosfora, kalijuma i sirovih proteina u uzorcima biomase su određivani tri puta tokom vegetativne sezone kukuruze, i to: u fazi intenzivnog porasta, fazi mlečno-voštane zrelosti i fazi pune zrelosti. Merenje prinosa zelene biomase obavljeno je krajem vegetacije. Rezultati istraživanja su pokazali da je primena visokih doza kompleksnih mineralnih đubriva i njihova kombinacija sa bakterijskim inokulantima uticala na povećanje sadržaja azota, fosfora, kalijuma i sirovih proteina u biomasi kukuruza tokom obe godine istraživanja, što je naročito izraženo u fazi njegovog intenzivnog porasta. Najveći porast prinosa biomase je dobijen na istim navedenim varijantama, a isto tako je i primena kombinacije bakterijskih inokulanata i manjih doza mineralnih đubriva rezultirala većim prinosima u odnosu na primenu manjih doza čistih mineralnih hraniva. Dobijeni podaci ukazuju da se ispitivani bakterijski inokulanti mogu koristiti u daljim istraživanjima kao potencijalni agenti novih biofertilizatora u cilju poboljšanja proizvodnje kukuruza i drugih poljoprivrednih kultura u ishrani životinja.

This paper presents the results of testing the quality of water for irrigation during the growing seasons 2012/2013, in the basin of the Kolubara River, from BeloAievac to Obrenovac, in three monitoring cycles on 16 selected sites belonging to agricultural area under irrigation. The determination of quantity of trace elements and heavy metals Cr, Ni, Pb, Cu, Zn, Cd, B, As, Fe, Hg was performed during mentioned period. The content of trace elements and heavy metals in the samples of water is generally below the maximum allowable concentration (MAC). In the samples No. 2, 3, 4, in the second series of sampling was recorded higher content of As above the MAC, which can be explained by drought, low water levels and potential anthropogenic pollution. In the other two cycles of monitoring are not registered concentrations of tested elements above MAC. Based on the presented and analyzed results of testing of hazardous and harmful substances in the water for irrigation of the Kolubara River, it can be concluded that it can be used for irrigation of crops and soil with restrictions and frequent quality checks during the summer months and control potential sources of pollution from industry.

To select isolates suitable for use in biological control of pathogenic fungi and as plant growth promoting (PGP) agents, Pseudomonas spp., indigenous to the rhizosphere of wild alfalfa and clover plants growing on the old magmatic hill Vagan (Serbia), were isolated. Isolates were selected on the basis of intrinsic antibiotic resistance (IAR) and PGP traits: phosphate solubilization, production of siderophores, hydrogen cyanide (HCN), acyl homoserine lactones (AHLs), indole acetic acid (IAA) and enzymatic activities. The results of the genotyping by repetitive sequence-based polymerase chain reaction, using ERIC and (GTG)(5) primers, and phenotyping by IAR clustered the isolates in five groups, represented by two isolates from alfalfa (Q1 and Q16) and three from white clover (B25, B28 and B29). Isolates Q16 and B25 showed production of HCN, IAA and AHLs. Good phosphate solubilization and production of siderophores were observed on Q1 and Q16. The Q16 isolate exhibited high enzymatic activity. The most promising PGP isolates, Q16 and B25, showed the best antifungal activity against Trichoderma viride, and good antifungal effect against Aspergillus fumigatus and Aspergillus niger, while Penicillium verrucosum was the most resistant fungus. Pseudomonas sp. B25 exhibited higher antifungal potential than Q16. The selected isolates could be further investigated as biological control agents and tested in field conditions to confirm their PGP efficacy. Serbian Ministry of Education, Science and Technical Development {[}III46007]

The wild plantain (Plantago major) is an important medicinal plant. Symptoms suggestive of phytoplasma diseases were observed in infected plantain plants in Serbia. A new disease on P. major has symptoms of reduced leaf size, leaf reddening and crinkling, and occasionally rolling of flowers and early drying up. This disease was found first on the plantain plantation in Pancevo locality, but later has been found in some other localities in Serbia (Kovin, Vrdnik). Restriction fragment length polymorphism (RFLP) analysis of amplification products of 1.2 kb, obtained in nested PCR with R16F2n/R16R2 primer pair after amplification with P1/16S-Sr primers, in 24 from 26 symptomatic plants indicated the presence of phytoplasma from the 16SrXII-A subgroup. Plantain plants collected from all three affected localities in Serbia were determined to be hosts of this phytoplasma. This is the first report of the natural occurrence of Stolbur phytoplasma in cultivated and wild P. major in Serbia.

Marshmallow is a host of a number of saprophytic and parasitic fungi in Serbia. The seeds of marshmallow are contaminated with fungi from different genera, especially Alternaria and Fusarium, which significantly reduced seed germination and caused seedling decay. In this study we investigate antagnonism of indigenous Bacillus sp. isolate Q3 against marshmallow mycopopulation. Bacillus sp. Q3 was isolated from maize rhizosphere, characterized by polyphasic approch and tested for plant growth promoting treats. Bacillus sp. Q3 produced antifungal metabolites with growth inhibition activity against numerous fungi in dual culture: 61.8% of Alternaria alternata, 74.8% of Myrothecium verrucaria and 33.6% of Sclerotinia sclerotiorum. That effect could be caused by different antifungal metabolites including siderophores, hydrolytic enzymes, organic acids and indole acetic acid (IAA). Suppression of natural marshmallow seed infection by Q3 isolate was observed. The seeds were immersed in different concentrations of bacterial suspension during 2h and their infections by phytopathogenic fungi were estimated. The results showed significant reduction of seed infection by Alternaria spp. The presented results indicate possible application of this isolate as promising biological agent for control of marshmallow seed pathogenic fungi. Beli slez gajen u Srbiji je domaćin mnogim saprofitnim i parazitskim gljivama. Seme je zaraženo gljivama iz različitih rodova, naročito Alternaria i Fusarium, ko je značajno redukuju klijavost semena i izazivaju sušenje. U ovom radu ispitivan je antagonizam autohtone bakterije Bacillus sp. izolata Q3 i mikopopulacije belog sleza. Bacillus sp. Q3 je izolovan iz rizosfere kukuruza, karakterizacija je izvršena polifaznom metodologijom i testirane su osobine odgovorne za stimulaciju rasta biljaka. Bacillus sp. Q3 produkuje antifungalne metabolite sa izraženom aktivnošću protiv fitopatogenih gljiva sa različitim procentom inhibicije rasta u dvojnoj kulturi: 61.75% kod Alternaria alternata, 74.80% kod Myrothecium verrucaria i 33.63% kod Sclerotinia sclerotiorum. Ovaj efekat je posledica produkcije različitih antifungalnih metabolita, uključujući siderofore, hidrolitičke enzime, organske kiseline i indolsirćetnu kiselinu (IAA). Ustanovljeno je suzbijanje prirodne infekcije semena belog sleza primenom izolata Bacillus Q3. Semena su potapana u različite koncentracije bakterijske suspenzije tokom 2 h i praćen je stepen infekcije fitopatogenim gljivama. Rezultati su pokazali značajan stepen redukcije infekcije semena belog sleza gljivom Alternaria spp. Ovi rezultati ukazuju na moguću primenu ovog izolata kao potentnog biološkog agensa za kontrolu infekcije semena belog sleza fitopatogenim gljivama.

Sweet William (Dianthus barbatus, Caryophyllaceae) is a biennial or short-lived perennial plant native to southern Europe, from the Pyrenees to the Carpathians and the Balkans. During the summers of 2012 and 2013, phytoplasma-like symptoms were observed on D. barbatus plants on a Serbian plantation (Pancevo, 44°51′49″ N, 20°39′33″ E, 80 m ASL). Only seven symptomatic plants were observed in the summer of 2012. Disease incidence in 2013 was estimated to be less than 1% but increased during 2014 to 4%. Affected plants, showing symptoms of leaf reddening, malformation, and proliferation; flower bud deficiency; and abnormal shoot production, were tested for phytoplasmas. Samples were collected from seven symptomatic and three symptomless plants each year (20 samples), and total nucleic acid was extracted from midrib tissue using a method that includes a phytoplasma enrichment step and DNA purification by chloroform/phenol (3). Oligonucleotide primers specific to the phytoplasma 16S to 23S rRNA intergenic spacer region were used in polymerase chain reaction (PCR) assays on DNA extracted from Sweet William plants (1,3). Using phytoplasma universal primer pairs P1/P7 and P1/16S-Sr, phytoplasma-specific 1.8- and 1.5-kb amplicons were obtained from four and six symptomatic plants collected in 2012 and 2013, respectively. Nested PCR with R16F2n/R2 primers yielded ~1.2-kb amplicons from DNAs of all symptomatic plants (1). No amplicon was generated in PCRs conducted with DNA templates from symptomless plants. Restriction fragment length polymorphism (RFLP) analysis of amplified 1.2-kb fragments was performed using four endonucleases (AluI, Tru1I, HhaI, and HpaII). Comparative analysis was done using RFLP patterns of Stolbur (Stol), Aster Yellows (AY), Flavescence Doree-C (FD-C), Poinsettia Branch-Inducing (PoiBI), and Clover Yellow Edge (CYE) phytoplasmas. PCR-RFLP patterns from tested samples were identical to those of the Stol reference strain, indicating that diseased Sweet William was affected by phytoplasma belonging to the 16SrXII-A (Stolbur) group. The sequence of a 1.2-kb rDNA PCR product derived from sample Tk9 (deposited under accession number KM401436 in NCBI GenBank) showed the closest identity (100%) to those of Bulgarian corn (KF907506.1), Iranian ‘Bois Noir’ (KJ637208.1), and two Serbian phytoplasmas (KJ174507.1 from Calendula officinalis and KF614623.1 from Paeonia tenuifolia), all belonging to the ‘Candidatus Phytoplasma solani’ Stolbur subgroup. Previously, Aster Yellows Phytoplasma (16SrI) had been detected in two Dianthus species: D. barbatus (Sweet William) and D. caryophyllus (carnation) (2). This is the first record of the 16SrXII-A phytoplasma subgroup being associated with yellowing and reddening of D. barbatus in Serbia. The Stolbur phytoplasma occurrence on Sweet William is significant for the management of the disease in Serbia. References: (1) I. M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998. (2) P. Northover et al. http://www.umanitoba.ca/faculties/afs/MAC_proceedings/proceedings/ 2007/Philip_Northover.pdf , 2007. (3) J. P. Prince et al. Phytopathology 83:1130, 1993.

Peony (Paeonia tenuifolia L.) is a herbaceous perennial plant known for its beautiful and showy flowers. In Serbia it is native to the Deliblato Sands and is used as an ornamental and medicinal plant in folk medicine. This plant species has become a rarity and for that reason peony was introduced into a botanical collection near Backi Petrovac (northern Serbia), where it has been maintained since 1988. Reddening of lower leaves observed on 10% of plants (5 of 50) in the collection at flowering in May 2012 gradually progressed throughout affected plants by the seed maturation stage. Five leaves from each of three reddened and three symptomless plants were sampled at the end of July 2012. Total nucleic acid was extracted separately from individual leaves (30 samples) using the CTAB (cetyltrimethylammonium bromide) method (2). A nested PCR assay using universal primer pairs P1/P7, followed by R16F2n/R16R2 (4), amplified 16S rDNA fragments of 1.8 and 1.2 kb, respectively. DNA from all three reddened plants (15 samples) yielded 1.2-kb amplicons after nested PCRs. Restriction fragment length polymorphism (RFLP) patterns obtained by digestion of nested products with endonucleases AluI, TruI, HpaII, or HhaI (Thermo Scientific, Lithuania) (4) were identical to those of the STOL reference strain included for comparative purposes, indicating that symptoms were consistently associated with plant infection by ‘Ca. Phytoplasma solani’ (Stolbur) phytoplasma. The 16S rDNA amplicons from two peony plants (1.2 kb from B15 and 1.8 from B18) were sequenced (GenBank Accession No. KC960487 and KF614623, respectively). BLAST analysis revealed a 100% identity between the sequences and GenBank sequences of Stolbur phytoplasma, subgroup 16SrXII-A phytoplasma, previously detected in maize (JQ730750) in Serbia and red clover (EU814644.1) in the Czech Republic. Phytoplasma associated diseases of other species of the genus Paeonia (P. lactiflora Pall. and P. suffruticosa Andrews) have been described elsewhere. Disease symptoms on P. lactiflora from Chile were associated with the phytoplasma that belongs to the ribosomal subgroup 16SrVII-A (‘Ca. Phytoplasma fraxini’) (1). Also, Stolbur phytoplasma from the 16SrXII group was detected on P. suffruticosa plants in China, manifesting yellowing symptoms (3). To our knowledge, this is the first report of naturally occurring Stolbur phytoplasma disease of P. tenuifolia L. in Serbia. References: (1) N. Arismendi et al. Bull. Insectol. 64:S95, 2011. (2) X. Daire et al. Eur. J. Plant Pathol. 103:507, 1997. (3) Y. Gao et al. J. Phytopathol. 161:197, 2013. (4) I. M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998.

The effectiveness of medicinal plants is mainly associated with their active constituents, but one of the major quality problems frequently encountered is their high trace metals content that can be associated to extensive pollution of the environment where medicinal plants grow. Therefore the aim of this research was to evaluate the content of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn and As in selected and frequently used medicinal plants, including chicory, broadleaf, common comfrey and dandelion. The plant material was collected from their wild habitats in the area of highly developed power plant activity during the summer of 2015. Plant analyses were done according to ICP methodology, using ICAP 6300 ICP optical emission spectrometer. The obtained results showed that the content of As, Cd, Co, Mn, Ni and Zn in the investigated medicinal plant species was below the maximum permissible concentration, while in all parts of all studied plants the concentration of Cr was toxic. The toxic concentrations of Cu were determined in root and aerial parts of chicory and common comfrey, and the toxic concentrations of Fe in root and aerial parts of dandelion and broadleaf plantain, and in aerial parts of common comfrey. However, high but not toxic content of Pb was found in aerial parts of chicory. It can be concluded that medicinal plants from the studied growing site are not appropriate for use in alternative medicine and that a determination of trace metals content in these plants must become a standard criterion for evaluation of their quality.