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Impact of different types of land cover on physical parameters of landscape surface
KUNTZMAN, Jan
The aim of the thesis was understanding the energy fluxes in different types of land cover. The area of interest is located in Novohradské hory in the basins of Váčkový and Pasecký potok. On a relatively small area there are five different types of land cover to be found (field, forest, permanent grassland, wetland and built-up area). For each of the types of land cover three properties of the surface were calculated: amount of vegetation on the surface, wetness of the surface and surface temperature. Moreover, soil heat flux, latent heat flux and sensible heat flux were established therefore surface thermal balance was evaluated. Results were statistically processed with boxplot diagrams as an outcome. The results support the hypothesis of vegetation having a positive effect on microclimate conditions. Especially the permanent cultures (wetlands, permanent grassland, forest) demonstrated much larger microclimatic stability and balance as well as capability of keeping moist. Thanks to insufficient intensity of vaporization (due to lack of water), built-up areas showed higher surface temperatures and sensible heat flux at most of the cases. Vegetation is capable of holding water and redistributing it in an environment via evapotranspiration. Thus, solar energy is stored inside of the water vapour which condensates on cool objects releasing the energy spent during the vaporization process. Water moves in the landscape through the local-scale water cycle stabilizing the microclimate.
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Crop water stress assessment using remote sensing approach
ERBEN, Jiří
The present thesis deals with evaluation of crop water stress by means of remote sensing. The first part of the research is focused on the assessment of water stress of sunflowers in a laboratory environment using spectral analysis of the reflected radiation and thermography. Leaf of suflowers temperature were evaluated and using them, the index of water stress CWSI were calculated. Reflection of leaf was evaluated in the wavelengths 350 -2500 nm. From these wavelengths spectral indexes were calculated - NDVI (Normalized difference vegetation index) which detect the presence of living green vegetation, WI (Water Index) which serve to calculate the approximate amount of water in the vegetation and RVI (simple ratio vegetation index) which determine the content of biomass or photosynthetic capacity. After that, they were compared with CWSI. Finally CWSI was compared with the spectral data, and from the resulting correlations they were apparent wavelengths, which correlated with given index more or less. The second part is focused on the assessment of water stress in terms of 4th. level catchment, specifically on catchment "Dehtáře" near Pelhřimov. There were primarily evaluated three biggest areas - fields of winter wheat, field corn and TTP.
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Analysis of long-term changes of vegetation indices
Beránková, Petra ; Jedlička, Jan (referee) ; Štych, Přemysl (advisor)
The work deals with the issue of research of long-term changes of vegetation indices concretely indices NDVI (Normalized Difference Vegetation Index). The first part is devoted to detailed analysis of domestic and foreign literature, which deals with the calculation and interpretation of vegetation indices values. The main theme of this work is to explore relation between temperature and NDVI changes and precipitation and NDVI changes over the period 1982-2006. These connections are examined using correlation and regression analysis. Attention is concentrated to the Czech Republic, Central Europe and Finland. The average value of NDVI in Central Europe increased over the study period of 0,0012 per year. The average value of NDVI in Czech Republic increased of 0,0014 per year. On the territory of the Czech Republic increased the value of NDVI in three seasons (spring, autumn and winter). In the summer, in some areas, decreased NDVI values. Correlation coefficients between NDVI and temperature and NDVI and precipitation appeared consistently the highest in the spring. Keywords: NDVI, vegetation indices, temperature, precipitation, Central Europe, Czech Republic
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Detection of drought events using combination of satellite data and soil moisture modelling
Semerádová, Daniela ; Trnka, Miroslav ; Hlavinka, Petr ; Balek, Jan ; Bohovič, Roman ; Tadesse, T. ; Hayes, M. ; Wardlow, B. ; Žalud, Zdeněk
The use of satellite data offers a potentially well usable tool to accurate drought monitoring. The study examines the space-time possibility of agricultural drought detection using freely available data from the MODIS instrument onboard Terra and Aqua satellites that reflects vegetation condition. Vegetation greenness metrics used in this study are based on the spectral reflectance curves in the visible red and near-infrared part of the spectrum and are expressed in relation to the average for the period of 2000-2014. The results are presented in weekly time step for the whole area of the Czech Republic, and are compared to the drought monitor system, based on the SoilClim dynamic model for soil water content estimates. These data, as well as other parameters, such as soil properties and land use, are integrated at 500 meters spatial resolution.
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Crop yield estimation in the field level using vegetation indicies
Jurečka, František ; Hlavinka, Petr ; Lukas, Vojtěch ; Trnka, Miroslav ; Žalud, Zdeněk
Remote sensing can be very useful tool for agriculture management. In this study, remote sensing methods were applied for yield estimation in the field level. There were compared remote sensing data together with yield data obtained from the field. The study area is located in Polkovice in Olomoucký region and a crop planted there in the year 2016 was spring barley as one of most important crops grown in the region. The study area in Polkovice is located at lower elevations with intensive crop production and is climatologically warmer and drier than other areas of the Czech Republic. Year 2016 was the first year when the harvest device has been used for yield analysis in this study area. The output of this method is the yield map displaying the amount of crop harvested in the particular place in the field. The yield data from the field were then compared with remote sensing data in the form of vegetation indices. Two of them were used for comparison – Normalized Difference Vegetation Index (NDVI) and a two-band Enhanced Vegetation Index (EVI2). These indices have been often used for yield estimation in different studies but mostly in larger scales. This study investigates use of NDVI and EVI2 at more detailed scale while using various remote sensing methods. Comparisons show that remote sensing data can provide accurate estimation and can be used for yield forecasting or supplement traditional ways of yield estimation. Results of the study show that yield-index correlations are stronger for satellite data than for the drone data. NDVI showed slightly stronger correlations than EVI2. Strongest correlations between vegetation indices and yields were found for NDVI from Sentinel 2.
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Zpracování a interpretace výnosových map jako podklad pro agronomické rozhodování
Širůček, Petr
Diploma thesis was focused on data yield map processing, their interpretation and analysis of relations with another spatial data. Aims of the work were identification error values, statistical process yield data and with help statistical methods evaluate correlation between yield map and another spatial data. Methods were based on gathering yield data with combine harvester during two years in corn and malting barley in conditions of farm. With using GIS and predefined tolls were removed error values from yield data and created yield maps. Subsequently, yield maps were analyzed with vegetation index NDVI, digital elevation model (DEM), sensor measurements of soil electrical conductivity and historical yield maps. In results was achieved removing from 11,3 to 13,8 % yield points in average, increasing of average yield from 3,6 to 4,7 % and decreasing of variation coefficient between 7,0 and 8,6 % with comparing original yield data and depending on planting crops during data yield processing. In case of evaluation of relations between yield map and NDVI obtained from satellite remote sensing was achieved moderately correlation by corn (r = 0,44) and malting barley (r = 0,65) in average depending on times of imaging and vegetative phase of the crop. In the evaluation relations between yield maps and DEM and slope was achieved weak and very weak direct and indirect correlation. Likewise, by soil electrical conductivity and yield was achieved very weak to negligible correlation. Conversely, the highest correlation was achieved between yield map and historical yield map (r = 0,63) in average. Obtained information serve as starting point for making agronomy decisions in conditions of particular farm in case of replacement of creating yield maps by prediction of yield based on another spatial data.
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Strniskové meziplodiny ve struktuře rostlinné výroby
Handlířová, Martina
This thesis deals with the production capabilities of stubble catch crops and their effect on yield of subsequent of spring barley. The field experiment was conducted on clayey-loamy fluvizem in the maize-growing region from 2006 to 2013. Experiments involved altogether ten different catch crops. Vegetation intercropping was established after the harvest of winter wheat in two periods (immediately after harvest crop and in mid-September). Spring barely was sown after these catch crops. Nitrogen fertilization was omitted to highlight the effect of catch crops on all variants in 2010. Analysis of the amount of fresh matter and dry matter stubble catch crops was conducted in the years 2006 - 2013 and the vegetation index NDVI was evaluated in the final year of monitoring. Another part belonged to classify the yield of spring barley grown after catch crops. A negative relationship between the yield of catch crop and that of spring barley was observed in the variant without nitrogen fertilization. Growing of catch crops on yield of spring barley had a positive impact in case of application of nitrogen.
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Using remotely sensed NDVI for drought impact assessment within selected crops
Hlavinka, Petr ; Trnka, Miroslav ; Semerádová, Daniela ; Dobrovolný, P. ; Balek, J. ; Možný, M. ; Štěpánek, P. ; Hayes, M. ; Svoboda, M. ; Wardlow, B. ; Žalud, Zdeněk
The relationship between Normalized Difference Vegetation Index (NDVI) and selected agrometeorological parameters (yields of selected crops, water balance) was investigated. The source for NDVI was Spectroradiometer MODIS within satellite Terra and it was available for grids in resolution 500 x 500 m from 2000 to 2010. The analysis was conducted within 12 grids spread through Southern and Central Moravian region. The information about cultivated crops (including spring barley, winter wheat, maize for grains, sugar beet and winter rape) were collected from the farmers and water balance simulated using SoilClim model.
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