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Modelling the onset of phenological phases of spring barley (Hordeum vulgare L.)
Dížková, Petra ; Bartošová, Lenka ; Hájková, L. ; Balek, Jan ; Bláhová, Monika ; Bohuslav, Jakub ; Pohanková, Eva ; Trnka, Miroslav ; Žalud, Zdeněk
The onset of phenological phases of plant species is influenced mainly by air temperature. Each phenophase has its temperature limits (base temperature and temperature sum), which must be reached for each phase to occur. With knowledge of these limits, it is possible to predict the onset of phenological phases in localities where only meteorological data are available and also in future climate conditions. In this work, we used phenological ground-based data from 33 stations within the Czech Republic to calculate the most relevant meteorological predictors. PhenoClim software was used for phenological and meteorological data calibration and modelling. The smallest error that allows us to predict the term of the phenophases was found for the heading of spring barley (Hordeum vulgare L.), as the best predictor was the maximum daily temperature and the statistical error was 3.6 days.
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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.
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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.
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Comparison of leaf area index dynamics and radiation use efficiency of C3 crops in the Czech Republic
Tripathi, Abishek ; Pohanková, Eva ; Trnka, Miroslav ; Klem, Karel
Leaf area index (LAI) and radiation use efficiency (RUE) are key parameters for plant growth and productivity.\nBecause of irregularities in weather conditions, accurate estimation of crop production requires\nunderstanding relationships between weather, LAI, RUE, and final production. It is thus important to\nstudy how the LAI dynamics, leaf area duration (LAD), and RUE are related to aboveground biomass production\nfor different crops. In our study, we compared aboveground dry mass production, LAI dynamics,\nRUE, and LAD in three C3 crops (spring barley [SB], winter wheat [WW], and oilseed rape [OSR]) in the\nCzech Republic. LAI was measured on the basis of transmitted photosynthetically active radiation, LAD\nwas calculated by counting the number of days in the growing season, RUE was measured using Beer’s\nlaw, and the aboveground dry mass was estimated at the time of harvest. Results of our study showed high\nbiomass production and RUE in SB while there was highest maximum LAI (LAImax) and LAD in OSR. We\nconcluded that LAI dynamics or LAImax do not fully reflect the crop production and that RUE may be considered\nas a better indicator for aboveground dry mass production.
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Effect of temeperature stress and water shortage on thousand grain weight of selected winter wheat varietes
Hlaváčová, Marcela ; Pohanková, Eva ; Klem, Karel ; Trnka, Miroslav
The aim of the presented study was to assess the effect of high temperatures and water shortage during anthesis on thousand grain weight (TGW) of two winter wheat varieties (Tobak and Pannonia). In addition, numbers of grains per spike were also assessed. The six growth chambers were used to simulate heat stress conditions within following gradient of temperature maxima: 26 degrees C (control chamber), 29, 32, 35, 38 and 41 degrees C. The relative humidity (RH) course and photosynthetically active radiation (PAR) intensity were controlled via protocols. Additionally, drought stressed (dry) and well-watered (wet) treatments were established within each growth chamber. The plants were removed from the growth chambers after 14 days and they were left until a full maturity, exposed to actual weather conditions. The TGW at 14% moisture were evaluated for particular treatments within both winter wheat varieties. TGW was generally more affected by high temperatures under drought stress than in well-watered conditions. The results revealed that Pannonia TGW was much more affected by the water deficiency in combination with high temperature (particularly 38 and 41 degrees C) than Tobak TGW.
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Effect of drought stress on selected winter wheat yield formation components within pot and field experiimental design
Hlaváčová, Marcela ; Pohanková, Eva ; Klem, Karel ; Hlavinka, Petr ; Trnka, Miroslav
The object of this study was to find out what is the behaviour of the same winter wheat variety (Bohemia) plants cultivated within pot and field experiment. Therefore, the main aim of this study was to verify (based on the pot experiment results) whether the pot experiment (that is limited by the soil area) does not substantially affect plant reactions. The pot experiment was carried out in growth chambers where daily temperature course, relative humidity (RH) and photosynthetically active radiation (PAR) were set via protocols. The pots were exposed to the drought stress for 14 days with the daily maximum temperature 26 °C from noon to 2 p.m. The pots were split into 2 groups: (1) Dry where the soil moisture within pots were maintained below 30% of the maximum water holding capacity, (2) Wet where the soil moisture did not decrease below 70% of the maximum water holding capacity. The plants within Wet variant were considered as a control group. The pots were placed onto the concrete floor of a vegetation hall (where the plants were exposed to the weather conditions) prior and after stress regime exposition. The field experiment was conducted within experimental station in Bystřice nad Pernštejnem belonging to the Bohemian-Moravian Highlands in the Czech Republic. The drought stress was established through the transparent roofs installed above plants’ tops level in the field. The control experimental plot without roofs was nearby there as well. The plants were harvested when the full maturity was reached and the selected yield formation components were evaluated.
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Assessing the impact of drought stress on winter wheat canopy by hermes crop growth model
Wimmerová, Markéta ; Pohanková, Eva ; Kersebaum, K. C. ; Trnka, Miroslav ; Žalud, Zdeněk ; Hlavinka, Petr
The main aim of this study was evaluate a drought stress effect on winter wheat development, growth (leaf area index), soil moisture and yields. Simultaneously, the ability of Hermes crop growth model to simulate drought stress response was tested. The field trial was established at Domanínek station (Bystřice nad Pernštejnem district, Czech Republic) in 2014. Mobile rain-out shelters for precipitation reduction were installed on the plots of winter wheat in May 2015. Results of this study showed that model is able to reproduce well a soil moisture content and to certain extent the drought stress for grain yields of winter wheat. Using the rain-out shelters (from 19 May to harvest on 6 August 2015), real winter wheat yields were reduced by 1.7 t/ha. The model was able to estimate the average yield with a deviation of 0.15 t/ha (6%) for no stressed variant. Model underestimated the yields for sheltered variant with a difference 0.67 t/ha (71%) on average against observed yields.
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The influence of reduced precipitation supply on spring barley yields and the ability of crop growth models to simulate drought stress
Pohanková, Eva ; Orság, Matěj ; Hlavinka, Petr
This paper evaluates the first year (2014) of results from a field experiment with spring barley (cultivar Bojos) under reduced precipitation supply. The field experiment was carried out at an experimental station in the Czech Republic and consisted of small plots in two variants and three repetitions. The first variant was uncovered, and the second was partly covered to exclude rain throughout the entire vegetation season. For plots’ partial covering, a material was used to divert rainwater away from 70% of the plots. The main aim was to determine whether there are any differences in soil water content or in grain yield size between uncovered and partly covered plots and to compare the results obtained. Data measured in this field experiment were used to compare simulations of this field experiment in the DAISY crop growth model. Subsequently, the crop growth model’s ability to simulate grain yield, which was affected by drought stress, was explored. In reality, differences in phenological development and grain yield size were not evident. Reducing precipitation supply in DAISY by about 70% led to simulations of covered plots with reduced grain yield in accordance with the initial hypothesis. Agreement between observed and simulated grain yield was evaluated using selected statistical indicators: root mean square error (RMSE) as a parameter of average magnitude of error and mean bias error (MBE) as an indicator of systematic error. RMSE of grain yield was 2.6 t ha−1. MBE revealed grain yield undervalued by 2.6 t ha−1.
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Application of growth models for local assessment of the impact of climate change on selected crops
Hlavinka, Petr ; Trnka, Miroslav ; Balek, Jan ; Dubrovský, Martin ; Pohanková, Eva ; Žalud, Zdeněk
This publication is focused on the description of specialized software named as crop growth models and its using emphasizing the application for climate change impact assessment at local scale. The ambition of this publication is to introduce brief history of the crop growth models development, its classification, actual trends of their progress and applications and last but not least, present procedure leading to the preparation of the input datasets, the initial setup, parameters calibration, validation through set of independent datasets and consequently the implementation of climate change scenarios for assessment of possible impact of future conditions on selected important field crops and set of representative sites in the Czech Republic.
Fulltext: content.csg -  PDF
Plný tet: Metodika_rustove_modely_2015 - PDF
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Analysis of Spring Barley Actual Evapotranspiration
Pozníková, Gabriela ; Fischer, Milan ; Pohanková, Eva ; Žalud, Zdeněk ; Trnka, Miroslav
Evapotranspiration (ET) represents the main water-loss part of the water balance in agricultural landscape. The reliable quantification of the agricultural field ET is, however, still a challenge. To calculate ET, the Bowen ratio/energy balance (BREB) method was used in this study. It is based on measurements of the temperature and humidity gradients and radiation balance with the soil heat flux. Calculated ET was further used to quantify crop coefficient (Kc). Subsequently, we analysed the crop coefficient of spring barley during one growing season since 7th May 2013 to 30th July 2013. We used the data obtained above 1-ha spring barley field in Bystřice nad Pernštejnem, Czech Republic. In particular, we investigated how Kc correlates to climatic conditions as rainfall and soil humidity and how it reflects Plant Area Index (PAI) during the year during different parts of growing season. The cumulative ET of spring barley was 228.6 mm per investigated period. For reference evapotranspiration (ETo) two different approaches were used. Typically, a reference grass cover 0.12 m high standard for Europe. On the other hand, in the USA it is common to use also alfalfa (0.50 m high). ETo of grass was 296.3 mm and ETo of alfalfa was 351.4 mm. Maximum Plant Area Index occurred in June and its value was 4.1. Mean Kc in May was 1.17 for reference grass and 1.03 for alfalfa. Similarly in June, Kc was equal to 1.16 (grass) and 1.03 (alfalfa). Finally in July, for reference grass Kc was 0.55 and 0.48 for alfalfa. The decline at the end of the growing season was caused by dry weather and ripe stage of spring barley.
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