Herbicide Dissipation from Soils with Different Herbicide use Histories

Weed Science ◽  
1987 ◽  
Vol 35 (4) ◽  
pp. 583-589 ◽  
Author(s):  
R. Gordon Harvey

Herbicide dissipation was monitored in soils differing in herbicide use histories. Repeated annual applications over 5 yr enhanced biodegradation of butylate [S-ethyl bis(2-methylpropyl)carbamothioate] and EPTC (S-ethyl dipropylcarbamothioate) but not alachlor {2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide}, atrazine [6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine], cyanazine {2-[[(4-chloro-6-(ethylamino)-1,3,5-triazin-2-yl]amino]-2-methylpropanenitrile}, or metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide]. Prior application of butylate or EPTC enhanced biodegradation of the other thiocarbamate herbicide but not alachlor, atrazine, cyanazine, or metolachlor. Prior application of alachlor, atrazine, cyanazine, metolachlor, or trifluralin [2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)benzenamine] did not enhance biodegradation of butylate or EPTC. Dissipation of EPTC applied with dietholate (O,O-diethyl-O-phenolphosphorothioate) was not enhanced by prior application of alachlor, atrazine, or trifluralin. Prior use of EPTC, EPTC + dietholate, butylate, or cycloate, respectively, enhanced biodegradation of EPTC in 100, 100, 71, and 50% of the experiments, of EPTC applied with dietholate in 57, 100, 60, and 33% of the experiments, of butylate in 33, 40, 100, and 20% of the experiments, and of cycloate in 0, 0, 17, and 0% of the experiments. Prior thiocarbamate herbicide applications usually did not enhance cycloate biodegradation, but soils from two locations without prior pesticide use histories rapidly degraded the herbicide. Storage of soil samples at 25 C for 6 or 12 months before application of EPTC and EPTC + dietholate resulted in less herbicide degradation than storage at 15 C. Differences in prior environmental conditions such as temperature may explain why development of enhanced biodegradation varied between years even in the same field plots.

1924 ◽  
Vol 16 (8) ◽  
pp. 486-488
Author(s):  
E. P. Deatrick ◽  
O. C. Bryan

Author(s):  
Jehan Khalil ◽  
Hasan Habib ◽  
Michael Alabboud ◽  
Safwan Mohammed

AbstractOlive mill wastewater is one of the environmental problems in semiarid regions. The main goals of this study were to investigate the impacts of different olive mill wastewater levels on durum wheat (Triticum aestivum var. Douma1) production and soil microbial activities (i.e., bacteria and fungi). A pot experiment was conducted during the growing seasons 2015/2017 to evaluate the effect of three levels of olive mill wastewater on both growth and productivity attributes of wheat. Vertisol soil samples were collected from southern Syria. Two months before wheat cultivation, three levels of olive mill wastewater: T5 (5 L/m 2), T10 (10 L/m2) and T15 (15 L/m 2) were added to pots filled with the collected soil samples. Also, a control (T0) free of olive mill wastewater was considered as a reference. Results showed a significant increase (p < 0.05) in germination rate (%), plant height (cm), ear length (cm), kernels number, kernels weight per ear (g) and grain yield (g/m2) compared to control. However, T5 treatment did not induce a significant increase in terms of ear length, kernels weight per ear or yield (in the second season). On the other hand, T10 treatment had recorded the best results compared with the other two treatments (T5, T15). Similarly, the results showed a significant increase in the number of bacterial and fungi cells by increasing olive mill wastewater concentration. This research provides promising results toward using olive mill wastewater in an eco-friendly way under Syrian conditions.


2002 ◽  
Vol 15 (2) ◽  
pp. 205 ◽  
Author(s):  
Christina Flann ◽  
Pauline Y. Ladiges ◽  
Neville G. Walsh

A study of morphological variation in Leptorhynchos squamatus (Labill.) Less. across its range in south-eastern Australia was undertaken to test the hypothesis that L. squamatus includes two taxa. Phenetic pattern analyses of both field-collected and herbarium specimens on the basis of morphology confirmed two major groups. Bract, cypsela, pappus bristle and leaf characters were particularly important in separating the two groups. The taxa are separated by altitude differences with one being a low-altitude plant found in many habitats and the other being a high-altitude taxon that is a major component of alpine meadows. Lowland plants have dark bract tips, fewer and wider pappus bristles than alpine plants, papillae on the cypselas and more linear leaves. A somewhat intermediate population from the Major Mitchell Plateau in the Grampians shows some alpine and some lowland characters but is included in the lowland taxon. Seeds from five populations (two alpine, two lowland and Major Mitchell) were germinated and plants grown for 18 weeks under four controlled sets of environmental conditions. The experiment showed that leaf size and some other characters are affected by environmental conditions, but that there are underlying genetic differences between the lowland and alpine forms. Leptorhynchos squamatus subsp. alpinus Flann is described here to accommodate the highland taxon.


Author(s):  
Ekta Sharma

The Presented summary paper target is to draw the attention of the public to the benefits of Environment and how we are connected to the Environment. To show that if there’s any change in the Environmental conditions, then how the conditions change in human beings lives. Living Being, whether a Human Being or Animals or plants,  are all directly or indirectly Dependent on the Environment for their Survival. When asked truly it can be said that none of the living being can survive without the presence of Environment. It is difficult to find absolutely natural environments, and it is common that the naturalness varies in a continuum, from ideally 100% natural in one extreme to 0% natural in the other. More precisely, we can consider the different aspects or components of an environment, and see that their degree of naturalness is not uniform.


1975 ◽  
Vol 19 (3) ◽  
pp. 301-304
Author(s):  
Ann E. Martin

The present study was conducted to investigate the effects of environmental conditions on visual workload. The environmental variables used were temperature, studied at levels of 45°F., WBGT, and 95°F., WBGT; and noise, studied at 83 dBA intermittent noise and 93 dBA continuous noise. Workload was defined as the amount of attention demanded from an operator as measured by performance decrement on a secondary task while performing a primary and secondary task simultaneously. The secondary task was reading random numbers, and the primary task was reading word lists. Significant differences (p<.05) were found between the control condition and all experimental conditions. The low temperature and high temperature-continuous noise conditions were significantly different from the other conditions. Noise and temperature were found to significantly increase workload (p<05).


2019 ◽  
Vol 188 (3) ◽  
pp. 860-864 ◽  
Author(s):  
Harry A Meyer ◽  
Hannah E Larsen ◽  
Nézira O Akobi ◽  
Garret Broussard

Abstract Tardigrade behavioural studies have focused on responses to abiotic environmental conditions. Predator–prey interactions have received some attention, but not how predators and prey might detect one another. Here, we investigate whether a predatory tardigrade species is attracted to, and a potential prey tardigrade avoids, areas previously occupied by the other. In our experiments, Milnesium lagniappe was the predator and Macrobiotus acadianus the prey. Petri dishes with non-nutrient agar were used as experimental arenas. In one treatment, we allowed Macrobiotus to roam over half of the agar for 20 h, while leaving the other half free of Macrobiotus. We then removed the prey and introduced the predator. In the control treatment, no prey were added. Results indicated that Milnesium individuals were significantly concentrated in the area previously occupied by Macrobiotus, whereas no such concentration was evident when Macrobiotus had not been present. A similar protocol was used to test whether Macrobiotus avoided areas previously occupied by the predator. As expected, Macrobiotus were significantly concentrated in the area never occupied by Milnesium, unlike the control treatment. These results suggest that both species can detect the other without physical contact and react accordingly. Given that the experiments were conducted in darkness, detection is probably olfactory.


1987 ◽  
Vol 1 (4) ◽  
pp. 341-349 ◽  
Author(s):  
R. Gordon Harvey ◽  
J. H. Dekker ◽  
Richard S. Fawcett ◽  
Fred W. Roeth ◽  
Robert G. Wilson

Research conducted since 1979 in the north central United States and southern Canada demonstrated that after repeated annual applications of the same thiocarbamate herbicide to the same field, control of some difficult-to-control weed species was reduced. Laboratory studies of herbicide degradation in soils from these fields indicated that these performance failures were due to more rapid or “enhanced” biodegradation of the thiocarbamate herbicides after repeated use with a shorter period during which effective herbicide levels remained in the soils. Weeds such as wild proso millet [Panicum miliaceumL. spp.ruderale(Kitagawa) Tzevelev. #3PANMI] and shattercane [Sorghum bicolor(L.) Moench. # SORVU] which germinate over long time periods were most likely to escape these herbicides after repeated use. Adding dietholate (O,O-diethylO-phenyl phosphorothioate) to EPTC (S-ethyl dipropyl carbamothioate) reduced problems caused by enhanced EPTC biodegradation in soils treated previously with EPTC alone but not in soils previously treated with EPTC plus dietholate. While previous use of other thiocarbamate herbicides frequently enhanced biodegradation of EPTC or butylate [S-ethyl bis(2-methylpropyl)carbamothioate], previous use of other classes of herbicides or the insecticide carbofuran (2,3 -dihydro-2,2 -dimethyl-7-benzofuranyl methylcarbamate) did not. Enhanced biodegradation of herbicides other than the thiocarbamates was not observed.


ÈKOBIOTEH ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 195-202
Author(s):  
A.I. Safonov ◽  
◽  
A.Z. Glukhov ◽  

From the data on the structural heterogeneity of indicator plants (Berteroa incana (L.) DC., Plantago major L., Reseda lutea L., Echium vulgare L., and Capsella bursa-pastoris (L.) Medik.) under unfavorable environmental conditions of Donbass selected their most informative characteristics for a general assessment of the level of anthropogenic load on local ecotopes. Empirical criteria were calculated as a result of correlation analysis between data sets on the content of heavy metals in soil samples and the values of phytoindication indices.


2018 ◽  
Vol 74 (2) ◽  
pp. 6074-2018
Author(s):  
WALDEMAR PASZKIEWICZ ◽  
KRZYSZTOF SZKUCIK ◽  
MONIKA ZIOMEK ◽  
MICHAŁ GONDEK ◽  
RENATA PYZ-ŁUKASIK

The objective of the research was to determine the occurrence of microorganisms of the Salmonella spp. and Listeria spp. in raw and frozen (cooked) snail meat obtained from both free-living and farmed edible snails. The research material comprised meat samples collected from three snail species (25g from each), that is, Roman snail (Helix pomatia – HP), small brown garden snail (Cornu aspersum aspersum – CAA) and large brown garden snail (Cornu aspersum maxima – CAM). Roman snails came from their natural environment and were harvested in Wielkopolska Voivodeship and Lower Silesia Voivodeship (regions A and B, respectively). The Cornu genus snails were obtained from two heliciculture farms located in the abovementioned voivodeships (farms A and B, respectively). On both farms, the snails were maintained under the mixed rearing system. The raw meat samples taken from the edible portion of snails, that is, the foot with collar and a fragment of the mantle, were obtained after the snails were sacrificed in the laboratory. The frozen meat samples, on the other hand, came from a snail meat processing facility. A total of 300 samples were examined for the presence of Salmonella spp., and 240 for the presence of Listeria spp. The research also included pooled soil samples of 0.5 kg each collected from polytunnels (in the pre-fattening stage) and outdoor farming plots (in the fattening stage). The tests for the Salmonella presence were performed in accordance with Polish standard PN-EN ISO 6579:2003, and the test for Listeria complied with PN-EN ISO 11290-1:1999. Listeria monocytogenes was identified by the PCR technique. Salmonella spp. were not detected in any of the 300 samples of raw and cooked snail meat under study. Nor were these pathogens isolated from the soil samples. The absence of these bacteria in the raw meat samples indicates that Salmonella spp. did not occur in either the natural habitat of Roman snails or the two farms producing Cornu genus snails. On the other hand, bacteria of Listeria spp. were detected in 101 (42.1%) snail meat samples. A particularly high load of microbiota was found in raw meat, as these bacteria contaminated from 60% (for HP from region A and CAM from farm B) up to 75% (for CAA from farm A) of samples. Notably, a markedly lower percentage (35%) of samples containing Listeria spp. was found only among the Roman snail raw meat samples from the region B. Listeria spp. were also detected in all the soil samples. Thermal treatment of meat achieved a substantial reduction in the load of Listeria spp., but did not eliminate it. The frequency of this genus in frozen meat samples was from 63.5% (for CAM from farm A) to 15.4% (for CAA from farm B) of that in raw meat. The PCR technique was used identify 15 selected strains, including 11 from raw meat samples and 4 from cooked meat. A total of 5 isolates were recognized as Listeria monocytogenes (2.1% of all samples examined and 4.95% of samples with Listeria spp.). All of them originated from the raw meat of farmed snails, including one (CAA) from the farm A and four (3 CAA and 1 CAM) from the farm B. Bacteria of the Salmonella and Listeria genera occur in the natural habitat of edible snails, which poses a potential hazard to human health. Effective implementation of control programmes at the primary production stage is the first step that could considerably limit the presence of these pathogens in farmed snails and, consequently, in snail meat. .


1964 ◽  
Vol 36 (1) ◽  
pp. 120-134
Author(s):  
Anna-Marja Halkilahti

In the petri dish trials the mycelia of Sclerotinia trifoliorum in sterilized soil samples generally infected clover quite readily. In unsterilized samples the infection was less severe and showed marked variations in different years and at different times of the year. In the outdoor trials clover became less infected in the middle of the summer than in the spring and autumn. On the other hand, in the thermostat trials, where the temperature was constantly 7—10°C, the temperature at the time of taking the soil samples did not have a pronounced effect on the extent of clover infection. Liming of the soil caused a marked decrease in the severity of clover rot infection. In some autumns clover plants growing in soil samples taken from fallow were more seriously infected than those growing in soil from a clover field. As a rule, however, there were only slight variations in the extent of infection in the soil samples taken at the same time from the various areas of the field cultivated in different ways. In general, the highest numbers of microorganisms in the soil were found in the autumn and the lowest in the spring. In clover fields there were often more microorganisms – particularly in the autumn – than in fallow. Liming caused an increase in the numbers of soil microbes. S. trifoliorum infected clover very severely at temperatures of 0—5°C; in the range 5—21°C the infection grew generally milder the more the temperature was found to be rising. At temperatures of 5– 10°C an increase in the numbers of soil microbes resulted in a decrease in the infection of the clover. Still higher temperatures, which did not increase the numbers of soil microorganisms, nevertheless enhanced the antagonistic power of the soil.


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