The temperature-dependent effect of residual nematicides on the activities of soil microorganisms

1973 ◽  
Vol 19 (7) ◽  
pp. 855-859 ◽  
Author(s):  
C. M. Tu
Keyword(s):  
Organic Nitrogen ◽  
Laboratory Experiments ◽  
Soil Microorganisms ◽  
Sulfur Oxidation ◽  
Microbial Activities ◽  
Temperature Dependent ◽  
Dependent Effect ◽  
Ammonium Production ◽  
Inhibition Of Nitrification ◽  
Fungal Populations

The effects of Dasanit®, carbofuran, D–D®, and Vorlex® on microbial activities in a loamy sand were evaluated in laboratory experiments at temperatures of 5 and 28C. Bacterial and fungal populations initially decreased with some of the fumigant treatments but the populations recovered after 2 weeks. D–D and Vorlex significantly stimulated ammonification of soil native organic nitrogen at 28C after 4 weeks. In some instances, fumigants decreased ammonium production from added peptone at low temperature. No inhibition of nitrification and sulfur oxidation was evident with any of the nematicides. The effect of fumigant and glucose treatments on the respiration of microorganisms at 15 and 30C showed that the inhibition period observed in the early stages of incubation was negatively correlated with the soil temperature.

Temperature-dependent effect of food size on the reproductive performances of the small-sized cladoceran Moina micrura

2015 ◽  
Vol 59 ◽  
pp. 297-301 ◽  
Author(s):  
Rui Chen ◽  
Nuo Xu ◽  
Feixi Zhao ◽  
Yingyuan Wu ◽  
Yuan Huang ◽  
...  
Keyword(s):  
Temperature Dependent ◽  
Dependent Effect ◽  
Food Size ◽  
Effect Of Food

The effects of age, temperature, light quantity and wavelength on the swimming behaviour of the cercariae of Cryptocotyle lingua (Digenea: Heterophyidae)

Parasitology ◽  
1992 ◽  
Vol 105 (1) ◽  
pp. 131-137 ◽  
Author(s):  
J. G. Rea ◽  
S. W. B. Irwin
Keyword(s):  
Life Span ◽  
Water Temperature ◽  
Light Source ◽  
Laboratory Experiments ◽  
Temperature Dependent ◽  
Release Point ◽  
Successful Transmission ◽  
Active Life ◽  
Light Quantity ◽  
Precipitous Decline

Laboratory experiments indicated that the active life-span of the cercariae of Cryptocotyle lingua was temperature-dependent. An increase in water temperature and population age both correlated with a tendency for the organisms to become decaudate. The larvae were strongly photoresponsive to lateral light but with time, horizontal swimming rates (HSRs) from release point to light source progressively declined. When measured over a range of light quantities, HSRs peaked at 30 μM/m2/s. HSRs were also influenced by water temperature. A rapid increase occurred up to 15 °C after which there was a precipitous decline. HSRs to coloured light were negatively correlated with increasing wavelength. When offered a choice between colours, cercariae favoured the shorter wavelengths. The implications of these responses for successful transmission are discussed.

scholarly journals The Influence of the Organic Matter of Sewage Sediments on Biological Activity of Microorganisms which Carry Out the Transformations of Carbon and Nitrogen Compounds

2013 ◽  
Vol 62 (4) ◽  
pp. 445-452
Author(s):  
IZABELLA PISAREK ◽  
KATARZYNA GRATA
Keyword(s):  
Organic Matter ◽  
Biological Activity ◽  
Organic Nitrogen ◽  
Soil Microorganisms ◽  
Natural Habitat ◽  
Transformation Process ◽  
Nitrogen Compounds ◽  
Soil Environment ◽  
Carbon And Nitrogen ◽  
Cellulolytic Microorganisms

Soil microorganisms play an important role in the organic matter transformation process. The soil microorganisms also are in symbiotic relationship with plants. At the same time, soil microorganisms are sensitive to both anthropogenic and natural habitat changes. Particular characteristics of organic matter (the C:N relation, pH, the content the content of assimilated nutrients, the xenobiotics etc.) modify the biotic conditions of the soils. This particularly concerns the microorganisms which carry out the changes in the mineral and organic nitrogen compounds and the transformation of the external organic matter. The first aim of this work was to assess the influence of the sewage sediments and the manure on the phytosanitary potential of the soil environment. The second aim of this article was to estimate the number and activity of microorganisms which carry out the transformation of carbon and nitrogen compounds. This work showed the stimulating effect of the external organic matter both on the number and on the activity of most of the physiological groups. The manure mainly stimulated ammonificators, amylolitic microorganisms and Azotobacter sp. The sewage sediments mainly stimulated ammonificators, nitrifiers of I phase and cellulolytic microorganisms. The statistically significant impact of the physio-chemical soil habitat on the biological activity of the analyzed groups of microbes was also noted.

Fate of14C-EPTC in a Soil Exhibiting Accelerated Degradation of Carbamothioate Herbicides and Its Control

Weed Science ◽  
1989 ◽  
Vol 37 (3) ◽  
pp. 434-439 ◽  
Author(s):  
Abraham Tal ◽  
Baruch Rubin ◽  
Jaacov Katan ◽  
Nadav Aharonson
Keyword(s):  
Methyl Bromide ◽  
Laboratory Experiments ◽  
Soil Microorganisms ◽  
Inhibitory Effect ◽  
Soil Sterilization ◽  
Soil Disinfestation ◽  
Herbicide Degradation ◽  
Chemical Treatments ◽  
Accelerated Degradation ◽  
History Of

Laboratory experiments were conducted to determine the fate of14C-EPTC in a soil that had a history of vernolate application and exhibited accelerated degradation of carbamothioate herbicides compared to nonhistory soil. A very rapid mineralization of the herbicide to14CO2was evident in history soil, compared to nonhistory soil. The two soils did not differ in the amounts of the EPTC lost through volatilization or in the nonextractable radioactive fractions. Except for small quantities of EPTC-sulfoxide and sulfone, no other metabolites were detected. Degradation of14C-EPTC, as determined by evolution of14CO2in history soil, was drastically inhibited following soil sterilization by means of autoclaving or gamma irradiation. Soil disinfestation by solarization, methyl bromide, or metham had a pronounced inhibitory effect during the first 6 days, but was less effective than sterilization. Treatment of a history soil with the fungicide 2-methoxyethylmercury chloride and dietholate strongly inhibited EPTC degradation, while thiram and fentin acetate had only short lasting effects. Cycloheximide, an antifungal antibiotic, had little effect on the degradation of EPTC while chloramphenicol, an antibacterial antibiotic, inhibited the herbicide degradation. These results indicate that accelerated degradation of EPTC is linked to the activity of soil microorganisms, e.g. bacteria, and can be controlled by sterilization and chemical treatments.

scholarly journals Laboratory experiments on shear failure of snow

1998 ◽  
Vol 26 ◽  
pp. 97-102 ◽  
Author(s):  
Jürg Schweizer
Keyword(s):  
Laboratory Experiments ◽  
Shear Failure ◽  
Failure Strain ◽  
Failure Stress ◽  
Homogeneous Layer ◽  
Strain Rates ◽  
Temperature Dependent ◽  
Direct Simple Shear ◽  
Dependent Property ◽  
Snow Samples

Using a direct simple-shear apparatus, snow samples (115 mm in diameter, 16–18 mm in height) taken from a so-called homogeneous layer (small rounded particles, density: 290 kg m−3) were tested in a cold laboratory. Experiments were performed for strain rates between 7 × 10−6 s−1 and 5 × 10−3 s−1 at test temperatures of −5°C, −10°C and −15°C. The effects of strain rate and temperature on failure stress, failure strain, stiffness (initial tangent modulus) and toughness were studied. The transition between the ductile and brittle (sudden fracture) state of failure was found to be at about 1 × 10−3 s−1 for the snow types tested, independent of temperature. Stiffness proved to be the most temperature-dependent property of alpine snow. It strongly increases with decreasing temperature. Failure strain and toughness decrease with decreasing temperature. Failure stress was found to increase slightly with decreasing temperature. The effect is not very distinct but close to statistically significant and might be partly hidden by the scatter in the stress data due to variations inherent in sampling and testing.

Temperature-dependent effect of percolation and Brownian motion on the thermal conductivity of TiO2–ethanol nanofluids

2016 ◽  
Vol 18 (22) ◽  
pp. 15363-15368 ◽  
Author(s):  
Chien-Cheng Li ◽  
Nga Yu Hau ◽  
Yuechen Wang ◽  
Ai Kah Soh ◽  
Shien-Ping Feng
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Brownian Motion ◽  
Thermal Storage ◽  
Temperature Dependent ◽  
Dependent Effect ◽  
And Brownian Motion ◽  
Potential Applications

Ethanol-based nanofluids have attracted much attention due to the enhancement in heat transfer and their potential applications in nanofluid-type fuels and thermal storage.

Foster, but not genetic, father plumage coloration has a temperature-dependent effect on offspring quality

2014 ◽  
Vol 69 (2) ◽  
pp. 335-346 ◽  
Author(s):  
P. E. Järvistö ◽  
S. Calhim ◽  
W. Schuett ◽  
W. Velmala ◽  
T. Laaksonen
Keyword(s):  
Plumage Coloration ◽  
Temperature Dependent ◽  
Offspring Quality ◽  
Dependent Effect

The cycle of atmospheric nitrous oxide

1979 ◽  
Vol 290 (1376) ◽  
pp. 495-504 ◽  
Keyword(s):  
Laboratory Experiments ◽  
Nitrogen Fertilizers ◽  
Time Range ◽  
Microbial Activities ◽  
Electrical Discharges ◽  
Soil Systems ◽  
To Come ◽  
Turn Over ◽  
Over Time ◽  
Horizontal And Vertical Distribution

An attempt has been made to construct an N 2 O balance of the troposphere in order to demonstrate the state of knowledge of the cycle of atmospheric N 2 O. This balance has been constructed considering the parameters relevant for atmospheric N 2 O as far as known such as the horizontal and vertical distribution in the atmosphere and in the oceans, the variation of the atmospheric mixing ratio with time, the fluxes in the air-sea and in the air-soil systems, and man-made fluxes. The total atmospheric burden of N 2 O appears to be in the range 1600-2100 Mt, the tropospheric turn-over time between 4 and 12 years. Most of the atmospheric N 2 O seems to originate from microbial activities at the Earth’s surface with the oceans apparently being the major source with about 35 % of the total source as obtained from the tropospheric N 2 O mass and turn-over time (range of uncertainty 5-100 %) followed by soil and fresh water with about 25 % of the total source (range of uncertainty 4-100 %) including the contribution of industrial nitrogen fertilizers with about 10 % of the total source (range of uncertainty 2-24 %). Direct man-made N 2 O sources seem to be relatively small with about 2 % of the total source (range of uncertainty 0.5-5 %), but may grow considerably in the future. The N 2 O production by chemical reactions in the troposphere itself (e.g. electrical discharges) is not known; a figure of between 3 and 70 % of the total source has been inferred from laboratory experiments. The sinks of atmospheric N 2 O are poorly known. The only known major N 2 O destruction appears to occur in the stratosphere. The rate of transport into the stratosphere, however, limits this sink to about 10 % of the total amount of N 2 O to be destroyed under steady state conditions (range of uncertainty 3-22 %). The major problem of the cycle of atmospheric N 2 O is the unknown main sink. Since the stratosphere does not seem to come into question, the missing sink should be found somewhere in the troposphere, pedosphere, and/or hydrosphere.

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