National Repository of Grey Literature 22 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Vliv chronické expozice chloridazonu a jeho metabolitu chloridazon desphenylu na raka signálního
The aim of this thesis was to evaluate the effect of chloridazon (Ch) and its major metabolite chloridazon desphenyl (Ch-D) at environmentally relevant concentrations 0.45 micrograms/l (Ch1; Ch-D1) and 2.7 micrograms/l (Ch2; Ch-D2) on adult signal crayfish (Pacifastacus leniusculus). The exposure was 30-day and followed by a 15-day depuration period. The effect of the tested substances was evaluated on the basis of behavior, biochemical profile of hemolymph, biomarker of oxidative stress and antioxidants parameters. The tested substances did not effect on the behavior of crayfish. Chloridazone at concentration 2.7 micrograms/l (Ch2) caused a significant (P<0.01) increase of glucose (GLU), lactate (LACT), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity in haemolymph of crayfish and changes in catalase (CAT) levels in the gills and the hepatopancreas, compared to controls. Crayfish exposed to chloridazon in both tested concentrations (0.45 micrograms/l and 2.7 micrograms/l) showed significantly (P<0.01) higher level of reduced glutathione (GSH) in hepatopancreas and gills compared to control. Exposure of chloridazon desphenyl at concentration 0.45 micrograms/l and 2.7 micrograms/l caused significantly (P<0.01) higher levels of glucose, lactate, ammonia (NH3), calcium (Ca), alanine aminotransferase and aspartate aminotransferase activity in haemolymph of exposed crayfish compared to control. Chloridazon desphenyl in both tested concentrations caused significant (P<0.01) changes in the levels of lipid peroxidation (LPO) in the hepatopancreas and catalase (CAT) and GSH level in the gills and hepatopancreas compared to the control group. Some effects persist after a depuration period. The results showed that the metabolite chloridazon desphenyl has more pronounced effects on the physiology of adult signal crayfish than its parent compound chloridazon. It can be stated, that chloridazon and its metabolite chloridazon desphenyl has the strongly negative and harmful effects of on crayfish as representatives of non-target aquatic organisms.
Biology and control of weeds in root crops (Solanum tuberosum Wild.)
In the theoretical part, agricultural techniques in the cultivation of potatoes were described and selected weed species were characterized, those that cause damage not only regarding root crops. Chemical protection is currently considered to be an important and most represented method for the regulation of weed species. It resides in the use of plant protecting herbicide products to limit the population of weed species below the economic hazard threshold. The practical part of the bachelor's thesis is focused on monitoring the biology and regulation of weeds in the cultivation of root crops (Solanum tuberosum Wild.). On an experimental plot of land managed by the Samohejl family near the village of Malešice (district České Budějovice) in the South Bohemian Region. Three potato varieties (Adéla, Belana, Marabel) and three different herbicides (Arcade 880 WG, Mistral and Sencor Liquid) were compared and the yield of tubers of cultivated potato varieties was monitored at the same time. The results showed that the effect was different for each herbicide. Due to their active substance (metribuzin), the small effect of these products was manifested on sow thistle and creeping spider. As a secondary result, the yield of tubers of individual varieties of potatoes in different treatments was monitored, when individual varieties responded to different herbicide treatments and thus provided different yields in these cases.
Způsoby regulace plevelů při pěstování kukuřice seté (Zea mays L.).
Corn is an important crop that is increasingly being applied and expanded in our countries. Due to the cultivation technology, weeding can significantly affect its yield. Weed control is mainly solved by the use of herbicides. One of the main objectives of this method is to achieve maximum effect at minimal economic cost. At the same time, the factor of minimizing negative effects on the environment is increasingly taken into account. The thesis describes the basic characteristics of maize, its basic agrotechnics and the extent of its cultivation in the Czech Republic. The basic characteristics and weed distribution are described, including the possibilities of their control. The actual work deals with the effectiveness of two combinations of herbicides used postemergence on land with different maize hybrids and evaluation of their effectiveness with regard to economic aspects.
Weed control in minimal soil cultivation
This work monitored weeds in three variants of soil cultivation. In three fields was used different variants of soil cultivation, first of them used disc stubble plough, second of this used stubble plough and third variant used classic plough. In this field test was monitored weedy in single years. In first years was be minimal soil cultivated variants more weedy then classic cultivated variant. In next years weedy go down.
New knowledge in the field of mechanism of action and use of auxin herbicides
Skůpa, Petr ; Petrášek, Jan ; Bárnet, M.
The methodology summarizes all the latest findings in the field of mechanism of auxin effects in the plant, which give users a new perspective on their use in agricultural practice.
Regulation of Weeds in Grown Hybrids of Maize
NAHODIL, Antonín
The degree work describes the biology and morphology of the weed plants, which are found in maize vegetation most frequently, as well as their spreading and possible regulation. Based on the findings acquired, the methods of chemical and mechanical regulation are described. The degree work describes briefly both the plant of maize itself and the process of its growing. The attempt took place on the school farm of the Agricultural School in Tábor; a small plot attempt was carried out at the same place. The frequency of the occurrence of weed species on the selected small plots was evaluated in the hybrids of maize (Zea mays). The degree work contains data on the extent of the occurrence of weeds on individual plots, on which the individual hybrids of maize were compared with one another. It also includes an economic evaluation and possible measures to eliminate the spreading of weeds.
Biology, presence and methods of weeds regulation on a land planted with permanent grasses.
This thesis is aimed at biology, presence and methods of weeds regulation on a land planted with permanent grasses. Lately, ruderal weed species have been spreading uncontrollably throughout the lawns. It is very difficult to control their occurrence and also very economically challenging. Therefore, the farms should focus more on the possibilities of preventing excessive weed infestation and they should also define and apply the cheapest and the most favorable precautions. On the grassland, which belongs to the ZD Třebelovice, were observed the most abundant weed species. The weeds which occurred the most were: Taraxacum Officinale, Rumex Obtusifolius L, Ranunculus Repens L., Geranium Pratense L., and Urtica dioica L. The influence of the individual hay cuts on the occurrence of the chosen weed species was monitored. The influence of various herbicides was also the matter of observance. The componential task was to appraise the achieved effect after applying chosen herbicides on the weed species.
Control of weeds in cultivated root crops
Damages, which weeds caused annually are difficult to quantify and its negative influence manifests annually in all crops and all fields.Chemical weed control is presently considered an important method for controlling weeds. The essence of chemical pest weeds consists in the use of herbicides to reduce weed species population under the economic threshold of harmfulness. In an effort to control weed populations using three methods: mechanical, chemical and biological. In the thesis was mapped weeds in potatoes on private land in Plasná, district of Jindřichův Hradec in region of South Bohemia. In the practical part of this thesis, I conducted an experiment that was aimed at monitoring the effects of selected herbicides in crops of potatoes. The aim of the experiment was to verify the effects of herbicides on the population most frequently occurring weeds in the root crops. The results showed that the herbicide is more effective for preemergence weed monitored. Assessment of weed infestation was carried out numerical method (ANOVA, Tukey = 0,05) in the ARM 8 (GyllingDataManage ment, Inc.) Spring 2013 - Fall 2013.
Biology, occurence and regulation possibilities of Viola arvensis Murray in grown plants
This thesis concerns on biology, occurrence and especially, herbicide regulation of Viola arvensis Murray on arable land. On the land of the farm DZV NOVA Bystřice a small-plot experiment focused on monitoring and regulation of Viola arvensis was carried out. This experiment was carried out from September 2012 to January 2014 on three crops (winter wheat, winter barley and winter rape) in three locations. In the theoretical part we describe the biology and occurrence of this frequent weed. The aim of the thesis was to evaluate the abundance of Viola arvensis and other weed species and verify the effect of different herbicides on Viola arvensis and other weeds. The effectiveness of the tested herbicide combinations was statistically significant for Viola arvensis and also for the other weeds (P 0, 05). The exceptions were Veronica persica, Geranium pussilum and Hordeum vulgare, where the effectiveness of these agents was not proved (P > 0, 05). The results summarize the numbers of weed species and effectiveness of applied herbicides. Viola arvensis was the most frequent weed species found on the examined sites. The effectiveness of herbicide agents used against this weed was very high. The highest was by preparations Maraton + Glean 75 WG, Maraton + Logran 20 WG, Cougar Forte + Logran 20 WG a Sumimax + Glean 75 WG (100 %). Lower was by preparations Butisan 400 SC + Command 36 SC (80 %) a Butisan Star + Garland Forte (75 %). In the winter barley and winter wheat, the applied herbicides were 100% effective, only in the winter rape the effectiveness was lower (75 - 80%). I can confirm the initial hypothesis about the effectiveness of the different herbicides on field pansy because their effectiveness differed.
Biology, occurrence and regulation Apera spica-venti tufted crops grown.
ORNA, Vítězslav
Over the last decades the amount of weeds in our fields have noticeably decreased. The easily annihilated and susceptible species were almost eradicated by means of herbicides and agrotechnical operations. Their place was taken by more resistant species, which are a huge problem for the farmers. For this purpose I decided to make an experiment under the working circumstances. I observed the occurrence of the weeds in certain localities. Especially I concentrated on the silky bent grass (Apera spica-venti), on its occurrence, regulation, extension and susceptibility or resistance to certain herbicides. The effect of the tested herbicide combinations was statistically significant for silky bent grass as well as for the other weeds (P 0.05). The coach grass was the only exception, where the effect of these preparations was not proved, as well as Vicia cracca, Lamium purpurem, Galium aparine, Geranium pusillum (P > 0.05). However the coach grass appeared among these inconclusively responsive weeds more frequently. (P >0.05). As the results of experiment showed, the most effective combinations for elimination of the silky bent grass (Apera spica-venti) were Sumimax + Glean, Cugar Forte + Glean + Dural a Cugar Forte + Logran. All these combinations were proved to be 100% effective against the silky bent grass (Apera spica-venti). The other combinations were not 100% effective. These comprised Rapsan + Command+ Grounded with 89 % effectivity, Sumimax + Logran 91 % effectivity a Butisan+ Clomate+ Grounded 67 % effectivity. The results show that the silky bent grass (Apera spica-venti) is more susceptible to some herbicide combinations and in the fields it can be successfully reduced. On the contrary the silky bent grass (Apera spica-venti) is resilient to some other agents. From this point of view the right choice of the herbicides is crucial in next year.

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