National Repository of Grey Literature 22 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Porovnání orebné a bezorebné technologie zpracování půdy z hlediska jejího zhutnění
MACH, Václav
The bachelor thesis focuses on technologies of soil cultivation which are nowadays most frequently used in our country and what is their influence in soil compaction. It describes reasons of the origins of soil compaction, impacts of the compaction and the effect of compaction on soil as a unit. It also focuses on procedure? against unwanted compaction or its following elimination. Subsequently, the thesis describes basic work operations which are plowing and aeration. There are details of the principle how the plough works, basic types of ploughs and the way how we can divide plowing. There are also methods of plowing which are applied in different conditions on land. Last but not least, the thesis points out advantages and disadvantages of this most common soil cultivation. It deals with technologies of aeration as well as it deals with machines which are able to cultivate soil or with technologies of soil cultivation and their advantages and disadvantages in work without a plough. The field experiment which has been done for drawing up of this bachelor thesis focuses on comparison of ploughing and non-ploughing technologies of soil cultivation in a way of its compaction. There is evaluation of the penetrometric resistance, of the achieved depth in measurement and the soil moisture. These values have been measured on a field which was divided according to the technology of soil cultivation. The first part was done conventionally with the plough and in the second part the plough was replaced with the aeration. The results of the measurement were then compared with the whole soil profile of the measurement, then in the depth of 20 cm and finally with rest the horizon of measurement. Values and comparisons of the individual measurements are for better illustration noted in tables and marked on graph.
Soil water retention in the landscape
Hřebejková, Barbora ; Šípek, Václav (advisor) ; Frouz, Jan (referee)
Water retention in the landscape is one the current topics in environmental protection. It is affected by a number of factors and is changing both in time and space. The goal of this thesis is to examine the long-term development of water retention in the landscape and to determine the influence of different types of vegetation on the soil moisture underneath. In the first part of my thesis I review different soil types with respect to their physical characteristics and interaction with water, and ways of measuring soil moisture. The aim of the thesis is the sum up the basic knowledge about soil and basics behaviour, mainly in the relation with soil moisture. There are introduced methods of soil moisture measurement with regard to their limits. In the second part I focus on analysis of selected studies covering the topic of water retention in the landscape. Due to the technical difficulty is only a few studies devoted to a long term measurement of soil water by direct methods and therefore are results mostly limited to evaluate soil water retention by hydropedological models. In the final part I discuss and evaluate the results of the aforementioned studies. Key words: water retention, soil moisture, evapotranspiration, soil hydrology, climate change
Soil moisture estimation using Sentinel-1 radar data
Outrata, David ; Štych, Přemysl (advisor) ; Potůčková, Markéta (referee)
Soil moisture estimation using Sentinel-1 radar data The main aim of this diploma thesis was to find and quantify the relationship between the intensity of backscatter from the Sentinel-1 radar data and the volume soil moisture at the level of agricultural fields. The research was conducted in three areas, in the first part there were two vegetation-free fields near the Thessaloniki (Greece), and information about soil moisture was obtained from own measurements using a thermogravimetric method. The second part drew data from the freely available ISMN database and the research was carried out on agricultural fields during the vegetation season in northwest Germany. The third part used soil moisture data from the Czech Hydrometeorological Institute (ČHMÚ) and the area of interest was two grassed areas of the airport and one agricultural field. Correlation was measured by calculating the determination coefficient and by using the linear regression an equation for calculating the soil moisture from the radar backscatter was compiled. High dependence has been confirmed when VV polarization with constant surface roughness were examined. In the case of surfaces with varying roughness and vegetation cover, only low correlation was found, similarly with using VH polarization. Key words: radar, SAR, Sentinel-1, soil...
Influence of land cover and altitude on soilmoisturespatio-temporal variability
Šípek, Václav ; Hnilica, Jan ; Tesař, Miroslav
An understanding of spatial and temporal variation of soil moisture is essential for studying other hydrological, biological or chemical soil processes, such as water movement, microbial activity and biogeochemical cycling (Bruckner et al., 1999, Ridolfi et al., 2003). Although the world-wide total amount of water stored in the soil profile is negligible compared to ocean and glacier storages, it represents a crucial variable concerning the water resources and agricultural management. This is valid especially in the context of ongoing shift in climate. Soil water exhibits a tremendous heterogeneity in space and time (Gomez-Plaza et al., 2000). Therefore, spatial and temporal variations of soil moisture have always been the critical issue. The spatial variability is influenced by variety of factors encompassing the topographical effect on lateral water redistribution (Williams et al., 2003), radiation (Grayson et al., 1997, Geroy et al., 2011), soil texture and structure (Famiglietti et al., 1998, Pan and Peters-Lidard, 2008), vegetation (Teuling and Troch, 2005), climate (Lawrence and Hornberger, 2007), precipitation pattern (Keim et al., 2005) and antecedent soil moisture (Rosenbaum et al., 2012). The land use influence on the soil moisture content variation is of complex a character covering several above mentioned factors. However, it is determined namely by the different vegetation cover, which results in different rates of interception and transpiration. It also strongly influences the soil hydraulic properties, i.e. hydraulic conductivity and water retention characteristics (Zhou et al, 2008). Hence, the reaction of an area to a rainfall and also the temporal variability of the soil moisture content might be influenced by the present land cover. Nevertheless, the studies comparing the influence of several land covers in the longer periods are missing. This knowledge would be valuable especially in the context of extreme climatic events that are present nowadays. In central Europe, the period of major floods (1997, 2002, 2013) was followed by serious dry spells (2003, 2011–2012, 2015) (Trnka et al., 2015). This observed hydrological extremity raised the questions of sustainable water management. One of the possible management practices in consideration is represented by the land cover changes intended to hold more water in the landscape and simultaneously to attenuate the rainfall-runoff response. Moreover, previous studies have investigated that spatial and temporal variation of soil water under a certain land use type, and drawing significant research attention is lacking on the differences of dynamics of soil water conditions under different land use types. Thus, it is necessary to understand the comparisons of the dynamics of soil water conditions under different land use types (Niu et al., 2015) The main aim of the presented study is therefore to understand the soil moisture variability in the vegetation season under four different land covers (coniferous/deciduous forest, meadow, grassland). This analysis is conducted in five consecutive years, encompassing both dry and wet periods. The influence of altitude is also studied in the coniferous forest.
Analysis of selected variations of the gravity due to the mass dynamics
Volařík, Tomáš ; Lederer,, Martin (referee) ; Vatrt, Viliam (referee) ; Mojzeš,, Marcel (referee) ; Weigel, Josef (advisor)
This dissertation is focused on a study of selected environmental effects influencing terrestrial gravity observations. Global geopotential models were used to compute quantities of the disturbing gravity field and its variations during time period. Furthermore, analyses of an atmospherical and hydrological effects on the gravity observations were provided. The computation was realized at the station Pecný, however the concept was proved and compared with data from station Strasbourg. Consequently, the results were discussed with respect to quasigeoid modelling established from gravity and astrogeodetic measurements. The result and recommendations for future research are exposed.

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