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Analysis of biological features of Capsella bursa-pastoris (L.) Med.
Schneebergerová, Tereza ; Hamouz, Pavel (advisor) ; Holec, Josef (referee)
The aim of this bachelor thesis is to determinate selected biological characteristics of shepherd´s-purse, which have impact on the establishment and expansion of its populations in field crops. In particular, development of primary dormancy was studied and the effect of factors that influence the dormancy and germination of seeds was determined.
Shepard´s purse is an annual or biennial herb of the cabbage family, which is classified as winter annual weeds. Primarily infest the winter and spring crops, rapeseeds, potatoes or forages. It appears from lowland to foothills, so biological features of individual population can be very different. The ways of control are shallow tillage or herbicidal treatment.
After harvesting of ripe seed the first experiment was set to define the primary dormancy. Remaining seeds were stored in two different types of environment. Part of seeds was stored in the dry at 20 °C. Others seeds were stratified at 5 °C. Effect of storage conditions on primary dormancy was tested every two weeks. Seeds were germinated for
1 week in grow chamber under the influence of various factors such as different light mode, type of water and type of media for germination.
The results were processed by multiple-factor analysis of variance. Fresh seeds showed a strong primary dormancy at constant temperatures of 10 °C and 20 °C. Treatment with fluctuating temperature (20/10 °C), filter paper, drinking water and stored in dark had the highest germination rate (10.75 %). Seeds stratified at 5 °C had increase in germination in first weeks, but lost it during storage. On the other hand, seeds stored in dry at 20 °C firstly were in dormancy, but they lost it gradually during storage.
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Analysis of weed spectrum in cereals in organic farming
Horáček, Jan ; Kolářová, Michaela (advisor) ; Holec, Josef (referee)
Summary
Organic farming means a chance for plants to reveal their abilities. We offer better conditions to the associated plants for their growth and reproduction by no use of chemical herbicides and by using alternative growing methods.
Organic agrophytocoenoses are significant by higher species richness and cover. There can be found some of endangered species among the weeds, which may be more successful in organic system, therfore the organic type of farming may serve for their protection. The most successful weed species endanger cultural crops on both organic and conventional fields. They become more dangerous without the possibility of herbicide application. Thanks to this, the strategy of each plant species is more important. That is why the question of weed suppression in organic farming is highly important and frequently asked.
The aim of this thesis is to analyse weed flora on organic cereals fields and to point out possible factors influencing them. Braun-Blanquet scale of dominance and abundance has been used for the assessment of weed communities. Several different localities were investigated in Benešov district. Influence of winter cereals, spring cereals, previous crop and the tillage system have been assessed.
Some of the most important weed species were: annual winter weed species in winter cereals, perennials and few annual spring species in spring cereals. Annual weeds were typical for spring cereals sown two years on a one plot, perennials were associated with spring cereals sown after fodder crops. -There were not found any evident differences in weed spectrum in winter cereals based on previous crop. Agrophytocoenosis on fields with conventional and reduced tillage differed. Wider spectrum of perennial species was typical for fields where reduced tillage was applied, differences in annual weed spectrum were also found. Typical species for conventional tillage were for example: marsh woundwort, common couch-grass and common poppy, while, creeping thistle, creeping buttercup, perennial sow-thistle, mugwort, corn chamomile, loose silky-bent and some others were often found on fields where reduced tillage were used.
The results of the analysis in this thesis mostly lead to the same description of weeds as in literature, but few of the results are different. Thanks to statistically decisive results, it is apparent, how a farmer can affect the plant associations over a long period.
Key words: organic farming, weeds, agrophytocoenosis, cereals, weed control, features(characteristic) of weeds.
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Occurrence of invasive plant species on slected locations of north-eastern part of Prague
Šebesta, Václav ; Holec, Josef (advisor) ; Václav, Václav (referee)
This thesis deals with the invasive plants in the northeastern part of the Prague. Data were obtrained from the monitoring during September 2015. The nomenclature of the species were united by Key to the Flora of the Czech Republic by Kubát et al. (2002).
A total of 18 species were found in 561 locations. The most numerous species from all locations include: Conyza canadensis (207 locations), Solidago canadensis (147), Robinia pseudoacacia (125), Symphoricarpos albus (89) and Parthenocissus inserta (77). The least numerous are: Pinus strobus (1), Reynoutria bohemica (6), Impatiens parviflora (7) and Rhus hirta (9). Five species from the designed species list were not found: Heracleum mantegazzianum, Reynoutria sachalinensis, Impatiens glandulifera, Senecio inaequidens and Rudbeckia laciniata.
Species that were most represented along the roads include: Solidago canadensis and S. gigantea, Conyza canadensis and Aster lanceolatus and A. novi-belgii.
Invasive species occurred in 75.6% in sunny locations, in 17% in the penumbra and in 7.5% in the shadow. In dry or drier water regime were found 90.5% of the species. 94.5% of the species were found in sandy and loamy soil. Low degree of coverage up to 10% of the area was found in about 50% sites of invasive species occurrence, average degree were 30% was found in 25% and a high degree of coverage was found in 25% sites of invasive species occurrence.
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Chemical weed management in potatoes
Smolík, Ondřej ; Hamouz, Pavel (advisor) ; Holec, Josef (referee)
Presented thesis is focused on the topic of regulation of weeds in potatoes. The advantages and disadvantages of chemical control of weeds are investigated, including the comparison of the results obtained in both herbicidal and mechanical treatments. The core of this thesis is to find out what kind of influence has weeds on potato yield and how is the weed infestation affected be herbicides. The research was undertaken by a field experiment with eight treatments. The first one brought a field completely without any interventions. On the second field a mix of Sencor Liquid (PRE), Command 36 CS (PRE) and Roundup Klasik (PRE) was used. The third treatment was sprayed by Sencor Liquid (PRE), Command 36 CS (PRE) and Pantera QT (POST). The fourth one was treated by both Sencor Liquid (POST) and Titus 25 WG (POST). The fifth treatment obtained only mechanical interventions (machine hoeing). On the sixth one Sencor Liquid (PRE), Command 36 CS (PRE) and Roundup KLASIK (PRE) were applied in combination with the mechanical treatmant. The seventh treatment used Sencor Liquid (PRE), Command 36 CS (PRE) and Pantera QT (POST), again combined with the mechanical treatment. On the last of the experimental fields Sencor Liquid (POST), Titus 25 WG (POST) and a mechanical treatment. Treatments 2-8 were compared to the first one. In this comparison it turned out that the herbicides help on a great scale with the regulation of the weed. By the treatments 2, 3, 6 and 7 the potato yield was three time higher compared to untreated control. Treatments 4 and 8 showed that the application of some post-emergent herbicides can (due to their phytotoxicity) decrease the yield to the level of the untreated plots.
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Beginning and duration of flowering period in selected arable weed species
Trefil, Daniel ; Holec, Josef (advisor) ; Václav, Václav (referee)
Arable weeds are usually perceived as harmfull organisms in crops. On the other hand, the weeds provide a stable source of food for insects and other invertabrates that feed on pollen and nectar. Majority of crops are not able to provide long-term food component for invertebrates because their flowering is synchronized. Arable weeds flower continously throughout the growing season. There is possible to find many flowering species for the whole year.
The main aim of the study was to determine the onset and duration time of flowering period for selected arable weed species. The observation was conducted at the Demonstration and experimental field of Faculty of Agrobiology, Food and Natural Resources neighbouring areas as well as demonstration plots with rare weed species that do not occur in fields naturally. Inventory of flowering species was performed weakly from 9th calendar week (after frost period) and finished at 48th calendar week. There were found and evaluated 160 plant species of which 67 were the rare species from demonstration plots.
First flowering weeds were photoperiodically neutral species, mainly from the group of winter annual weeds followed by ephemeral annual weeds. Among others, the late-flowering species were particulary from the group of summer annual weeds, but also some from perennial species.
During the first week of observation, 11 flowering species were found. The number gradually increased up to a maximum of 118 flowering species in the 27th calendar week; then the number of flowering plant species naturally decreased. Newly flowering species were being found until 36th calendar week. Weed differed significantly in onset of the flowering acording to perenniality, in most cases. Length of flowering period in individual species was in relation to particular families.
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Occurrence of invasive species Eragrostis albensis in Prague and its surroundings
Mikulka, Jakub ; Holec, Josef (advisor) ; Jursík, Miroslav (referee)
Eragrostis albensis is an invasive weed. For invasive species it is typical that they are easily spread in to all manner of localities. Eragrostis albensis is recently described species, which spreads along the Elbe and the Vltava river. The purpose of this bachelor thesis was to find new places of occurrence in Prague and its surrounds and especially around the Vltava river. There were found a few locations where the occurrence of Eragrostis albensis was confirmed and these areas were always ruderal. At most of the areas there were maximum 3 plants. Only in one locality there were over 70 plants of Eragrostis albensis (locality Dvořákovo nábřeží). This invasive weed has wide ecological amplitude, it occurs especially on embankment nearby river, but it can also grow on pavements affected by dry. This species well tolerate disturbed areas and floods can help this weed to create new suitable locations. According to this monitoring it´s obvious, that Eragrostis albensis is a part of some ruderal districts in Prague.
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Crop structure and crop sequences in ZOD Vacov
Vyleťalová, Lucie ; Holec, Josef (advisor) ; Hamouz, Pavel (referee)
Crop rotation can be defined as an effective crop rotation in space and time according to crop requirements and production plans, it is the concrete implementation of structural cropping patterns in the company, which forms the basis of crop production.
The aim of this paper is to outline the issue of crop rotations and sequences depending on the mountainous area of production. To determine the importance and usage, briefly describe the most used crops in the company, their needs and usage. Analysis of the structural representation in comparison with recommended proposals of several authors dealing with this issue. This work is focused on agricultural commercial cooperative Vacov, located in the foothills of the Bohemian Forest, which now covers an area of 200 ha of arable land. The main focus of the production is livestock production. Crop production is concentrated on the production of grain and roughage for cattle. All data utilized in this work were obtained from the records of the ZOD Vacov and represent the period of
2007-2015. After their evaluation, crop sequences of the company were compared methodologies of several authors.
The share of winter crops and spring crops is almost equal due to frequent changing of winter wheat and corn. Other crops often used are spring barley, oats and winter triticale. Most used forecrops and successive crops of winter wheat are corn, spring barley and oats. Most used forecrops and successive crops of corn are winter wheat, spring barley and winter triticale. Crop sequences in comparison with crop rotation specialized in mountainous areas are significantly poorer in structure. The most used crops are grains and corn, which is regarded as root crop. Fodder, specifically shamrock or clover mixture is used only at a few locations, although it should be included in all sequences. The main reason for the growing of maize and wheat in such concentration is to focus the company on a livestock production. Ensiled corn and wheat straw are used as bedding.
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Monitoring of the flowering time of selected arable weed species
Suran, Pavel ; Holec, Josef (advisor) ; Kolářová, Michaela (referee)
Flowers have an irreplaceable role in a sexual reproduction of plants. Flowers also offer the nutrients to high ammount of the insect species, both pollinators and parasitoid imagos. These insect species are depending on a beginning and a lenght of the plant flowering period and some are depending as well on a plant species diversity. Therefor it is important to monitor a flowering time of individual weed species.
The phase of the plant flowering is started, as well as by other things, by a certain temperature and a humidity. Some species might require a different value of these parameters. The beginning and the lenght of the weed flowering should correlate with a development of the temperature and the humidity during the observation period. This monitoring period was the year of 2015 and observed area was the Demontrational and experimentational land of the Faculty of Agrobiology, Food and Natural Resources of the Czech University of Life Science in Prague. During the observation period, the plant flowering times of the individual weed species were recorded on a weekly basis. In this study, the beginning and the end of the plant flowering time were evaluated for every weed species, that were observed on the observed area. Several of the observed species registered a pause in the flowering time, this pause was also evaluated. It was found out, that most of the species, that start flowering in the spring, started flowering roughly one or two months earlier. The plants capable of flowering during a moderate freezes flowered untill the very late autumn or even during november. The plant species, that start thein flowering in the summer were not affected by an increase in the temperature of the first months, but they were affected by the very high summer temperatures and these species stopped flowering and they either never flowered again, or they started flowring, once the temperature dropped.
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