National Repository of Grey Literature 36 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Jurečka, František ; Hlavinka, Petr ; Lukas, Vojtěch ; Trnka, Miroslav ; Anderson, M. ; Hain, C. ; Balek, Jan ; Bláhová, Monika ; Žalud, Zdeněk
Actual evapotranspiration (ETa) determined by the Atmosphere-land Exchange Inverse (ALEXI) model and water balance model SoilClim was compared for selected districts of the Czech Republic. The ALEXI model uses the land surface temperature (LST) from remote sensing and provides information on ETa and subsequently the surface moisture status. The SoilClim is a dynamic model of watcr content in soil and represents a model based on water balance approach. The current version of the model is able to estimate the value of ETa, as well as soil moisture content in two layers of the soil profile. Investigated period of ETa comparison were years 2014 and 2015. Especially the year 2015 had a special relevance due to the significant summer drought that occurred in CR. Model performance was compared for the period when changes in vegetation are most significant from April to August. Week sums of ETa from both models were compared at the district level for Vysodina, JihomorayskY and Olomouck, regions. The ETa values were generally higher from ALEXI as compared to SoilClim. ALEXI values were in some cases even two or three time higher. Moreover, the seasonal dynamics showed sometimes opposite trends. As this is a pilot testing of ALEXI based ETa in the conditions of Central Europe and show large differences as compared to well established methods, more detailed testing is required prior drawing any general conclusions.
Regional yield forecasting for improved decision making in the plant production
Trnka, Miroslav ; Hlavinka, Petr ; Kudláčková, Lucie ; Balek, Jan ; Meitner, Jan ; Možný, Martin ; Štěpánek, Petr ; Bartošová, Lenka ; Semerádová, Daniela ; Bláhová, Monika ; Lukas, Vojtěch ; Žalud, Zdeněk
The methodology describes how to predict yields of key crops, and at the same time addresses reliability of the predictions and how these can be used. The ability to predict yield levels more than 2 months prior the harvest on the level of regions (NUTS3¨) and districts (LAU1) brings also new opportunities to mitigate impacts of adverse conditions. The methodology shows that the yield forecasts and yield anomalies in particular are consistent and usable in practices. In this methodology, the results of 2018 yield forecasts are presented as an example. The yield forecasting system for the Czech Republic is fully functional and is and will be available through
Using growth models to evaluate field crops management practices and influence on soil processes
Hlavinka, Petr ; Trnka, Miroslav ; Balek, Jan ; Dubrovský, Martin ; Pohanková, Eva ; Wimmerová, Markéta ; Žalud, Zdeněk
The publication describes the application of growth model for evaluation of different farming methods in the cultivation of selected field crops and their influence on selected soil processes and conditions. This publication focuses on complex simulations in the soil-plant-atmosphere-farmer interaction system using the HERMES model. The ability to simulate processes in crop rotation scheme continuously and uninterruptedly (e.g. over a period of more than 100 years) gives the opportunity to assess the long-term trends in soil processes, both due to different approaches to farming and combined with selected location and soil conditions. It is possible also for selected scenarios of climate change in future. This material presents both the outputs for weather conditions without any considered climate change and conditions reflecting the shift in climatic conditions during the 21st century based on 6 selected climatic scenarios. The expected impacts on the growth and yields of the target field crops are also quantified for the selected combination of conditions.
Foliar application of zinc reduces the risk of drought stress on poppy (Papaver somniferum L.)
Škarpa, P. ; Richter, R. ; Hlavinka, Petr ; Trnka, Miroslav
Especially in arid regions, drought stress is considered as one of the main reasons for yield reduction of plant. Zinc, as one of the essential microelements in crop plant, plays a crucial role in resistance to drought stress. The objective of the vegetation experiment established in 2011-2015 on locality Zaboice was to explore the effect of the foliar zinc application on the yield of poppy in interactions with weather conditions observed years. Effect of zinc foliar application was significantly dependent on the average daily air temperature (r =-0.936). Foliar application of zinc increases production of poppy seed, in the range from 6.9 to 25.5 % and the efficiency of zinc foliar fertilization increases with a widening deficit rainfall calculated as the difference between the precipitation sum and reference evapotranspiration of poppy growing season (r =-0.9072). In general, the results of the present study indicate that usage of zinc foliar application reduces the harmful effects of water deficit stress and increases resistance to drought stress in poppy plant.
Evaluating drought risk for permanent grasslands under present and future climate conditions
Trnka, Miroslav ; Schaumberger, A. ; Formayer, H. ; Eitzinger, Josef ; Hlavinka, Petr ; Semerádová, Daniela ; Dubrovský, Martin ; Možný, M. ; Thaler, S. ; Žalud, Zdeněk
Over the past years, the changing climate has affected parts of Czech Republic and Austria by drought spells of the intensity and extend that was unprecedented in previous decades. These events had a significant impact on agricultural areas, especially on the grasslands. The idea behind the GIS monitoring relies on hypothesis that the effect of weather and climate conditions on the grassland production can be estimated by models that describe certain natural processes in a simplified manner and in spatialized form.
System for monitoring and forecast of impacts of agricultural drought
Trnka, Miroslav ; Štěpánek, Petr ; Chuchma, F. ; Možný, M. ; Bartošová, Lenka ; Hlavinka, Petr ; Balek, Jan ; Zahradníček, Pavel ; Skalák, Petr ; Farda, Aleš ; Semerádová, Daniela ; Meitner, Jan ; Bláhová, M. ; Fiala, R. ; Žalud, Zdeněk
The methodology describes how to predict soil moisture and drought intensity, and at the same time addresses reliability of the predictions and how these can be used. The ability to predict soil moisture values over a period of up to 9 days is presented through using ensemble of models for numerical weather forecasts. This method brings also new opportunities to mitigate impacts during drought events by farmers using such forecasting tools. With regard to the relatively high predictability of soil moisture and drought intensity, the methodology introduces the basic procedures and provides necessary information for the users. In this methodology, the results of 2017 drought event are presented as an example. The drought forecasting system for the Czech Republic is fully functional and is and will be available through
Effect of artificially induced drought on growth and productivity of selected crops within field experiment in Bohemian-Moravian highlands
Wimmerová, Markéta ; Hlavinka, Petr ; Trnka, Miroslav ; Žalud, Zdeněk ; Pohanková, Eva
The field experiments based on manipulating the crop environment are critical for determining the crop’s response to the climatic conditions expected in the future. An experimental site in Domanínek is located by 49°31'42 N, 16°14'13 E at an altitude of 560 m (potato production area). The field experiment using rain-out shelters for soil water availability reduction was conducted in 2015/2016. The main aim of this study was to assess the impacts of different water availability (rain-out shelters vs. control) on the performance of selected field crops (spring barley, winter wheat, winter rape and silage maize). Reduction of precipitation in treatment with rain-out shelters was confirmed by measuring soil water content. The amount of precipitation during growing period was reduced by 251 mm, 277 mm, 217 mm and 240 mm for the spring barley, winter wheat, winter rape and silage maize, respectively. As a consequence, leaf area index and yields declined, however the crop responses were not consistent.
Towards a combining of remote sensing and in situ evapotranspiration measurements
Fischer, Milan ; Jurečka, František ; Anderson, M. ; Hain, C. ; Pozníková, Gabriela ; Hlavinka, Petr ; Orság, Matěj ; Lukas, V. ; Žalud, Z. ; Trnka, Miroslav
This study provides preliminary results from combining in situ Bowen ratio energy balance (BREB) and\nevapotranspiration (ET) measurements techniques with physically based remote sensing ET estimates determined\nby the Atmosphere-Land Exchange Inverse (ALEXI) model. Evapotranspiration measurements\nand ALEXI estimates were analysed in an agricultural area close to Polkovice, Czech Republic during 2015,\nwhen a drought spell and intensive heatwaves appeared in the country. The BREB system was monitoring a\nwinter wheat (Triticum aestivum L.) field (~26 ha) while the ALEXI pixel (~5 km resolution) covered a wide\nrange of crops, including mainly winter wheat, spring barley, and winter rape. The study results showed that,\nalthough the applied methods work at different spatial scales (field vs. landscape), their combination can provide\nfurther insights into ET at both scales. For instance, such approach can be used to identify whether a specific\necosystem investigated in situ contributes to cooling or warming of the landscape.
Application of multispectral remote sensing indices for sensing indices for estimating crop yields at field level
Jurečka, František ; Lukas, Vojtěch ; Hlavinka, Petr ; Semerádová, Daniela ; Fischer, Milan ; Žalud, Zdeněk ; Trnka, Miroslav
Remote sensing can be used for yield estimation prior to harvest and can replace or complement classical\nways of estimating crop yields. This study was undertaken in Polkovice, located in the Czech Republic’s\nHaná region. For 2015 and 2016, two data sets of satellite imagery were used: the Moderate Resolution\nImaging Spectroradiometer and the Landsat 8. Vegetation indices from satellites were compared with crop\nyields at the level of land blocks. Winter wheat and spring barley yield data, representing crops planted\nover the analysed period, were used for the comparison. The results of the index–yield comparison showed\nthat vegetation indices from remote sensing data provide reliable information for yield estimation prior to\nharvest. Indices are also able to evaluate the spatial variability of a crop within the field. The results showed\nthat remote sensing data need to have detailed spatial resolution in order to provide reasonable information\nabout yield at such a detailed level.
Water-use efficiency of winter wheat under heat and drought stress
Hlaváčová, Marcela ; Klem, Karel ; Novotná, Kateřina ; Rapantová, Barbora ; Urban, Otmar ; Hlavinka, Petr ; Smutná, P. ; Horáková, V. ; Škarpa, P. ; Trnka, Miroslav
Because such extreme weather events as dry spells and heat waves are expected to occur more frequently\ndue to climate change, the issue of appropriate water management for sustainable agricultural production\nis increasingly important. This study focuses on wheat, the second most widely grown cereal in the world\nand the most common cereal in European countries. The study assesses the effects of short periods (3 and\n7 days) of high temperatures (26°C as a control, 32°C, 35°C, and 38°C as daily temperature maxima from\n12:00 to 14:00) and drought stress at different developmental stages (DC 31 – beginning of stem elongation,\nDC 61 – flowering, and DC 75 – early grain filling) on water-use efficiency (WUE) in winter wheat\ncultivar Tobak. This cultivar is one of the most widespread winter wheat cultivars in Czech Republic fields.\nThe analysis of WUE showed that the cv. Tobak plants were able to withstand drought stress conditions\nthrough increased WUE. In contrast, wheat plants were stressed more markedly if exposed to higher temperatures\nand drought in combination. Generally, the wheat plants were most sensitive to drought at DC\n31.

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