Wyniki wyszukiwania - Biblioteka Nauki

1

Changes in live microbial biomass content in soil after long- term herbicide application

100%

Przybulewska K. , Pruchniewicz A.

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2008

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tom Vol. 15, nr 7

649-655

EN

The present study aimed at determining the effect of long-term application of four different triazine and urea herbicides on live soil microbial biomass content. Soil biomass content was measured with Wösthoff-Ultragas U4S analyzer with an addition of easily assimilable source of carbon (glucose). The examined herbicides induce changes in the quantity of live microbial biomass in soil after their long-term application. On average, the effect of Gesagard is stimulatory, whereas three other herbicides induce a decrease in biomass quantity by 20-30 % when compared with control. The modifying effect of herbicides on soil microflora quantity is mainly visible in the surface layer of soil (0-10 cm), while being small in the 10-20 cm horizon.

PL

Badania miały na celu określenie wpływu wieloletniego stosowania czterech różnych preparatów z grup herbicydów triazynowych i mocznikowych na zawartość biomasy żywych mikroorganizmów glebowych. Zwartość biomasy w glebie mierzono w analizatorze Wosthaff-Ultragas U4S z dodatkiem łatwo przyswajalnego źródła węgla (glukoza). Badane herbicydy powodują po wieloletnim stosowaniu zmiany w ilości biomasy żywych mikroorganizmów w glebie. Średnio wpływ Gesagardu jest stymulujący, pozostałe trzy herbicydy powodują zmniejszenie ilości biomasy o 20-30 % w porównaniu z kontrolą. Działanie herbicydów zmieniające ilość mikroflory glebowej jest widoczne głównie w powierzchniowej warstwie gleby 0-10 cm, w poziomie 10-20 cm wpływ ten jest niewielki.

2

The impact of a shelterbelt on soil properties an microbial activity in an adjacent corp field

84%

Wojewoda D. , Russel S.

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2003

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tom Vol. 51, nr 3

291-307

EN

Studies were carried out in a 8 years old shelterbelt planted across croplands (D. Chłapowski Landscape Park, region of Wielkopolska, western Poland) and in the easterly adjacent field. The effect of the shelterbelt on: soil organic matter content, soil respiration, microbial biomass, dehydrogenase activity, mineralization potential of N and total number of bacteria and fungi in the upper soil layer was analysed. Samples were collected along parallel sites situated in the central part of the strip (S), in the wood edge (Es), field edge (Ef) and in the field 10 m (F10) and 50 m (F50) away from the strip. All studied microbial parameters, except for plate counted total numbers of bacteria and fungi, showed a high and significant correlation with soil respiration and microbial biomass. The highest values were found in the wood soil, lowest in the field soil and intermediate in the field edge. Marked vertical differences between layers 0-3 and 3-10 cm were noticed on sites S, Es and Ef while stratification in the field was visible not earlier than 11 months after ploughing. Some parameters: soil organic matter contents, dehydrogenase activity, microbial biomass estimated by fumigation-extraction method and mineralization potential of N, showed a regular pattern along the gradient from the shelterbelt to the middle of the field. The study suggests a favourable effect of a shelterbelt on organic matter content in the adjacent field. This effect may increase with age of the wood strip.

3

Biodegradation of diesel fuel in soils modified with compost or bentonite and with optimized strains of bacteria. Part I. residues of diesel fuel components in soil and changes in microflora activity

67%

Nowak A. , Nowak J. , Telesiński A. , Hawrot-Paw M. , Błaszak M. , Kłódka D. , Przybulewska K. , Smolik B. , Szymczak J.

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2008

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tom Vol. 15, nr 6

483-503

EN

The rate of degradation of diesel fuel components in a sandy and day soil was determined. Compost or bentonite additives and inoculation with selected bacteria strains were used for stimulation of the process. During incubation, residues of diesel fuel components and microbial biomass content, dehydrogenases activity and adenylic energy charge, were determined. In the sandy and day soil, diesel oil residues decreased during the experiment to 0.44-8.68 % and 4.35-11.72 % of the applied dose, respectively. The half-life periods in the sandy soil were 1 to 10 days shorter than in the day one. Soil additives induced a shortening of the half-life periods even by half, especially in sandy soil. Also the inoculation with bacteria caused an in-crease of degradation rate, especially combined with compost or bentonite. Susceptibility of diesel oil components to degradation decreased in the following order: isoparaffins and monoaromatic compounds, then n-paraffins, and n-paraffins and P AH at the end. Compost and bentonite in the sandy soil increased degradation in particular for P AH, monoaromatic compounds and isoparaffins. Monoaromatic compounds and n-paraffins responded to inoculation treatment in a shortening of the t1/2 periods, with a similar additional response of P AH in the sandy soil and of naphthenes in the day soil. During diesel fuel degradation, an increase in the soil microbial biomass content, increase of dehydrogenases activity and high AEC (adenylate energy charge) values was observed. The introduction of modifying additives into soil increases the activity of microflora. Positive correlations were observed . between microflora activity parameters, as well as negative ones between those parameters and diesel fuel residues in soil.

PL

W badaniach określano szybkość zanikania oleju napędowego w glebie lekkiej i ciężkiej. W celu przyspieszenia tego procesu stosowano do gleby dodatki modyfikujące: kompost lub bentonit oraz szczepienie wybranymi szczepami bakterii. Podczas inkubacji gleby wykonywano oznaczenia pozostałości składników oleju napędowego oraz zawartości biomasy żywych mikroorganizmów, aktywności dehydrogenaz oraz ładunku energetycznego (AEC). Pozostałości oleju napędowego zmniejszały się w glebie lekkiej i ciężkiej podczas inkubacji odpowiednio do 0,44-8,86 % i 4,35-11,72 % w stosunku do zastosowanej dawki. Okres połowicznego zanikania był w glebie lekkiej 1 do 10 dni krótszy niż w ciężkiej. Dodatki modyfikujące powodowały skrócenie czasu połowicznego zanikania nawet o połowę, zwłaszcza w glebie lekkiej. Również szczepienie gleby bakteriami powodowało przyspieszenie rozkładu, zwłaszcza w kombinacji z dodatkiem kompostu lub bentonitu. Szybkość zanikania składników oleju napędowego zmniejszała się w kolejności: izoparafiny i skład-niki monoaromatyczne, następnie n-parafiny i nafteny, najwolniej zanikały WW A. Kompost i bentonit w glebie lekkiej powodowały przyspieszenie rozkładu zwłaszcza WWA, składników mono aromatycznych i izoparafin. Związki monoaromatyczne i n-parafiny reagowały na szczepienie gleby skróceniem czasu połowicznego zanikania, podobnie reagowały WWA w glebie lekkiej i nafteny w glebie ciężkiej. Podczas biodegradacji oleju napędowego obserwowano zwiększenie w glebie ilości biomasy żywych mikroorganizmów, aktywności dehydrogenaz oraz wysokie wartości ładunku energetycznego. Wprowadzenie dodatków modyfikujących do gleby powodowało wzrost aktywności mikroflory. Zaobserwowano dodatnią korelację pomiędzy różnymi parametrami ak-tywności mikroflory, jak również ujemną pomiędzy tymi parametrami a pozostałością oleju napędowego w glebie.

4

Effects of freezing and freeze-thaw cycles on soil microbial biomass and nutrient dynamics under different snow gradients in an alpine meadow (tibetan plateau)

67%

Liu L. , Wu Y. , Wu N. , Luo P. , Xu J. , Mao Y. , Zhang L.

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2010

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tom Vol. 58, nr 4

717-728

EN

In alpine zones, cold season processes, particularly those associated with snow accumulation and ablation, have a central role in ecosystem functioning. However, we know very little about soil carbon and nitrogen processes under the snowpack in these ecosystems, including the Tibetan Plateau. We conducted an experiment comparing three snow regimes (11 m x 1 m plots) of different snow depths and durations at an altitude of 4,100 m in the Minshan Range on the eastern Tibetan Plateau. The three snow regimes included a shallow and short duration snowpack (SS; depth <10 cm), a moderate snow depth and medium duration snowpack (MS; depth <20 cm), as well as a deep and long duration snowpack (DS; depth > 30 cm). This study explores the effects of different snow conditions on soil temperature, and further describes the sequence and timing of dissolved nutrients and microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) in soils under different snow regimes during the autumn-winter transition (i.e. November 7, 2008 - March 7, 2009). Three successive phases of temperature change were distinguished: I - initial decline - soil temperatures dropped steadily from 4[degrees]C to about 0[degrees]C at the same rate for all three snow regimes; II - moderate freezing - soil temperatures fluctuated between 0[degrees]C and -7[degrees]C under all three snow regimes; III - multiple freeze-thaw cycles took place in the SS and MS regimes, but permanent freezing occurred in the DS regime. Under moderate freezing, we found that soil temperature fluctuation was an essential factor for the transformation of soil C and N. Our results indicate that larger temperature fluctuations correlate with a greater increase in dissolved organic nitrogen (DON) content. Dissolved organic carbon (DOC) content increased markedly only under the most drastic temperature fluctuations. In contrast, MBC content increased significantly only when soil temperatures were relatively steady. Under the permanent freezing, only a large number of freeze-thaw cycles caused a significant decline of NO[^][3] -N and DOC concentrations. DON content declined markedly under permanent freezing and multiple freeze-thaw cycles. However, MBC content declined significantly only under permanent freezing. Ultimately, multiple freeze-thaw cycles resulted in the export of dissolved nutrients (organic and inorganic nitrogen) from the alpine ecosystem which had previously accumulated in the moderate freezing phase of the soil.