Ograniczanie wyników

Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 63

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 4 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 4 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
In the presented studies, an attempt has been made to utilise enzymatic indicators for the estimation of soil environment reaction to the applied differentiation of organic fertilizers and maize (Zea maysL.) cultivation.The two-year experiment was held on a field. In different development stages of maize, the activities of protease, dehydrogenase and acid phosphatase were determined in the soil. The activity level of the selected enzymes was defined using the spectrometrical method. The results obtained from the studies, show that applied organic fertilization, as well as the cultivation of soil had only a minor effect on the activity of the analysed soil enzymes. In case of dehydrogenases, it was found that their activity in the time of the experiment was the highest after the manure incorporation into the soil. In case of phosphatase, its highest activity was recorded in the soil fertilized with sewage sludge (5 t d.m. ha⁻¹ year⁻²).
The problem of sewage sludge composting is the subject of many scientific investigations. If the process of composting runs properly, a consequent dominance of determined types and groups of microorganisms in connection with the successive changes in temperature occurs. In this paper, changes in the number of mesophilic and thermophilic bacteria were examined in the process of composting sewage sludge together with all sorts of additions. Influence of the differences in the composition of compost on bacteria development dynamics was also examined. Colonies of bacteria isolated on selective culture mediums were the base for determining the total number of bacteria in the compost. Relation between the activity of dehydrogenases and the number of mesophilic and thermophilic bacteria was also examined. It was estimated that the composition of compost and pH did not interact with the number of mesophilic and thermophilic bacteria during the composting process. Existence of relation between the decrease in the number of microorganisms and the increase in T (temperature) was observed. On the basis of the obtained results, it was also found that the activity of dehydrogenases positively correlated with the number of mesophilic bacteria.
Microbiological characteristics of sewage sludge from a mechanical-and-biological sewage treatment plant composted in controlled conditions with straw and sawdust are presented. Prepared composts were placed in four bioreactors with airflow of 4 l air·min⁻¹. In bioreactor K1, K2 and K3 the composted mass consisted of 65% sewage sludge (K1–sewage sludge 1, K2 – sludge 2, K3 – sludge 3) + 30% sawdust + 5% straw; while in bioreactor K4 the proportion was: 45% sludge 2 + 50% sawdust + 5% straw. Compost samples were taken from all chambers at the same time, depending on actual temperature. Microbiological analyses consisted in the determination (by plate method) on selective media of the numbers of mesophilic and thermophilic bacteria, fungi and pathogenic bacteria Salmonella sp. Clostridium perfringens and Enterobacteriaceae. Furthermore, in the experiment, the activity levels of dehydrogenase were determined using 1% triphenyltetrazole chloride as substratum. Studies have indicated that the composting process caused a decrease of the number of fungi and pathogenic bacteria from Enterobacteriaceae family and Clostridium perfringens in all composted matters, as well as an increase in the number of thermophilic bacteria. Changes in the number of mesophilic bacteria depended on the compost type. In composts K1 and K2, the composting process caused an increased proliferation of cells, while in the composts K3 and K4 the number of mesophilic bacteria decreased. On the basis of the obtained results, it was also found that in the majority of analysis terms, the lowest activity of dehydrogenases occurred in compost K3, while their level of its activity, in the majority of the studied composts, correlated most intensively with the number of thermophilic bacteria.
The objective of the performed investigations was to assess the influence of the value of temperature, pH, gas emissions, and doses of BAF microbiological inoculum on the reduction or total elimination of bacteria from the Enterobucteriaceae family. The performed experiment consisted of two stages. In the course of the first trial, sewage sludge was subjected to composting together with straw and sawdust in a cybernetic bioreactor. The experimental design included three treatments, two of which were inoculated twice with BAF inoculum: K1 - control, compost without inoculation; K2 - compost+1500 ml BAF; K3 - compost+750 ml BAF. The BAF (Bacteria-Actinomycetes-Fungi) inoculum was designed at the Department of General and Environmental Microbiology of Poznań University of Life Sciences and was made up of bacterial strains, actinomycetes, and mould fungi isolated from mature compost. The microbiological analyses applied in this experiment involved determination of total counts of bacteria belonging to the Enterobacteriaceae family using, for this purpose, Koch's plate method followed by biochemical tests confirming species membership of the above-mentioned bacteria. In the second part of the experiment, bacteria from Escherichia, Klebsiella, and Citrobacter genera isolated from mature composts were subjected to the ring method with the aim of examining mutual interactions between the above-mentioned bacterial species and the BAF inoculum. On the basis of the obtained research results, it was found that the recorded reduction in numbers of the discussed microorganisms was caused by physico-chemical factors of the composting process, especially by the inoculation of biowastes by the BAF biopreparation. The performed in vitro analysis of interactions between the Escherichia coli, Citrobacter freundii, and Klebsiella pneumoniae strains and the applied BAF inoculum revealed considerable sensitivity of the above strains to the experimental biopreparation. However, in in vivo conditions, E. coli bacteria exhibited resistance to the action of the above dose of the inoculum. Therefore, continuation of the above investigations appears necessary.
The authors investigated the impact of different sewage sludge doses (4 tons and 6 tons d.m./ ha) and manure (20 tons w.m./ha) on the developmental dynamics of soil microorganisms as well as on the soil respiration activity. The experiments were carried out in field conditions. Spring barley was used as the test plant. It was found that the addition into the soil of organic matter in the form of sewage sludge and manure failed to cause any statistically significant changes in the total bacteria number. Positive correlation between the total bacteria number and the amount of the C02 released from the employed soil objects occurred in the all combinations.
Two inoculums: Effective Microorganisms (EM) specimen available on the market and microbiological BAF1 inoculum, were applied in the experiment. The plants were cultivated in the growth chamber equipped with shelves with fluorescent or LED lamps. The highest number of inflorescences was under the influence of white color of light emitted by fluorescent lamps and blue color of light emitted by LED lamps, especially after application of BAF1 inoculum. Irrespective of microbiological inoculum, no significant effect of the color of light and type of lamps on such traits as height of leaves layer, number of leaves, greening index of leaves (SPAD) and length of inflorescences, was found. The white color light emitted by fluorescent lamps stimulated actinobacteria multiplication, especially after EM application. Regardless of the inoculum application, it was the blue color light emitted by LED lamps that stimulated the multiplication of moldy fungi. After the use of fluorescent lamps, the increase in dehydrogenase activity was observed, especially after the application of BAF1 inoculum. The activity of acid phosphatase was stimulated by blue and white+blue light emitted by LED lamps. The increase in the activity of urease was observed under fluorescent lamps emitting the green, blue and white color of light, after the application of EM.
Ilość i stan wody w glebie wywiera zasadniczy wpływ na wzrost, rozwój i aktywność życiową mikroorganizmów. Przyjmuje się, że bakterie nie rozwijają się na ogół przy mniejszej wilgotności środowiska niż 30%. Grzyby są pod tym względem bardziej wytrzymałe od bakterii, gdyż ich rozwój ustaje przy wilgotności mniejszej niż 15%. Celem podjętych badań było określenie wpływu deszczowania na liczebność w glebie wybranych grup drobnoustrojów, tj. bakterii, promieniowców, grzybów i bakterii z rodzaju Azotobacter oraz aktywność dehydrogenaz glebowych. Doświadczenie zlokalizowano na terenie ZDD Złotniki, należącego do Uniwersytetu Przyrodniczego w Poznaniu, na glebie płowej typowej, należącej do kompleksu przydatności rolniczej żytniego bardzo dobrego i przeprowadzono w latach 2007-2008. Na 8 poletkach doświadczalnych wysiano kukurydzę odmiany Clarica FAO 220, z przeznaczeniem na ziarno. Połowa poletek była deszczowana w okresie wegetacji roślin, gdy wilgotność spadała do poziomu 70% polowej pojemności wodnej. Próbki glebowe do analiz pobierano w 6 terminach w sezonie wegetacyjnym: przed siewem (kontrola), faza 2-3 liści, faza 7-8 liści, wyrzucanie wiech, dojrzałość mleczna i po zbiorze. Analizy mikrobiologiczne przeprowadzono na podłożach wybiórczych, metodą płytkową, oznaczając ogólną ilość bakterii, promieniowców i grzybów oraz liczebność bakterii z rodzaju Azotobacter. Aktywność dehydrogenaz oznaczono kolorymetrycznie. Stwierdzono istotny wpływ fazy rozwojowej kukurydzy oraz deszczowania na liczebność drobnoustrojów oraz aktywność enzymów w glebie. Aktywność dehydrogenaz w I roku analiz była wyższa na obiektach deszczowanych, natomiast wyższą liczebność mikroorganizmów w większości analizowanych terminów obserwowano na poletkach niepoddawanych zabiegowi deszczowania.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 4 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.