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The response of field‐grown vegetables to adverse weather conditions is strongly coupled to the timing of adverse events, the sensitivity of the growth stage of the impacted crop and the management actions that are taken. To estimate the long‐term yield response to changes in temperature and precipitation as well as the short‐term response to key adverse weather events (e.g. heavy precipitation, drought and heat stress) on the yields of vegetable crops, we used several statistical approaches with six daily impact‐indicators, the four monthly drought indices and the climate trends. Our study integrated a newly available historical yield dataset at the district level (the finest spatial resolution) for all highly marketable vegetables (celeriac, late carrots, root parsley, early kohlrabi, summer savoy cabbage, late cauliflower, late cabbage, onions, green peas, tomatoes, salad and pickling cucumbers) and a high‐resolution historical climate dataset (seven daily meteorological variables at a 10 × 10 km resolution) over a 54‐year period in the Czech Republic (CZ). Different indices were used to reflect different dimensions of water and heat stress, which have different impacts on vegetable growth and yield. We find positive long‐term impacts of recent warming on fruiting vegetables (from 4.9 to 12.2% °C−1) but decreases in the yield stability of traditionally grown root vegetables in the warmest areas of the country. Short‐term extreme temperature variabilities (days with heat stress) were found to be the dominant type of adverse event for tomato and cucumber production due to its effect on increased soil water demand, which increased transpiration rates, whereas changes in both the diurnal temperature ranges and minimum temperature (Tmin) were associated with minimal risk of frost damage. Brassicas vegetables are widely irrigated in the CZ, but irrigation does not fully mitigate drought effects; hence, short‐term extreme precipitation variability largely controls crop production in the growing districts. The high frequencies of dry days and days with heavy precipitation within the critical growth stages of brassicas reflect a competition between more dry days and greater precipitation intensity on wet days. The yield variability of bulbs is largely explained by both short‐term extreme precipitation and temperature variability (drought‐heat stress), which reflects the predominantly rain‐fed system of onion cultivation. Both drought and heat stress and changes in Tmin were important in explaining yield losses of root vegetables. Legumes had the lowest risk of multiple stresses during their short growth cycle, but droughts remain the dominant type of adverse event. Years with yield gains were substantially more common than years with yield losses for brassicas, bulbs and legumes vegetables in all of the cultivated regions.

The main objective of this study was to project changes in the evolution of drought characteristics (frequency, duration and magnitude) during the 21st century in lowlands, highlands and mountainous regions in the Czech Republic (CR). We focused on the multi‐scalar nature of droughts as a function of the variables that govern the balance of moisture during climate change, such as precipitation, which supplies moisture, and temperature, which modulates evapotranspiration. Thereby, this issue is addressed with two drought indices, i.e. the standardized precipitation evapotranspiration index (SPEI) and the standardized precipitation index (SPI), for various lags (1, 3, 6, 12 and 24 months). To assess the impact of climate change on drought characteristics, a set of eight regional climate models (RCMs) simulations were selected for further analysis driven by five different global circulation models (GCMs) carried out in the frame of Euro‐CORDEX. Future drought changes were developed for the two representative concentration scenarios (RCP4.5 and RCP8.5). For the temporal evolution of the droughts, the monthly drought indices were calculated over the entire study period from 1961 to 2100. The SPEI showed a higher frequency in the categories of severe droughts and extreme droughts than the SPI, while the SPEI yielded fewer events in the extreme wet categories. The probability distribution of the SPEI‐6 under the RCP8.5 scenario shifted more than one and a half standard deviations in lowlands at the end of the century, peaking at −1.65 (with a probability of 10.5%). This meant that severe droughts, according to the current climate criteria, will become the new norm in the period 2071–2100.

This paper presents the methodology for assessment of drought episodes and their potential effects on winter and spring cereal crops in the Czech Republic (in the text referred to as Czechia). Historical climate and crop yields data for the period of 47 years have been integrated into an agrometeorological database. The drought episodes were determined by three methods: according to the values of the standardized precipitation index (SPI), percentage of long-term precipitations (r), and on the basis of the Ped drought index (S i ). Consequently, the combined SPI, S i , and r indices have been used as tools in identification of the severity, frequency, and extent of drought episodes. Additionally, the paper also presents the S i drought index and its potential use for real-time monitoring of spatial extension and severity of droughts in Czechia. The drought risk to crops was analyzed by identifying the relationships between the fluctuation of crop yields and drought index (S i ) based on the multiple regression analysis with stepwise selection. In general, models explain that a high percentage of the variability of the yield is due to drought (more than 45% of yield variance).

ABSTRACT. The study is focused on drought stress that is detrimental to yield formation of field-grown vegetables in the lowland regions of the Czech Republic. Extensive vegetable yield losses are attributed to drought, often in combination with heat or other stresses. The objective of this research was to investigate, under field conditions, the effect of drought stress quantified by the Standardized Precipitation Evapotranspiration

This research aimed to identify an approach for adaptation of agriculture to increased climate variability and projected changes, taking into account regional specificity of climate change. Changes in the timing of growing season (GS) parameters for both observation and models data were computed using daily mean temperatures for three thresholds that correspond to the physiological requirements of the vegetable types. This research included a new assessment of the potential impacts of climate change on the GS of vegetables grown in the Elbe River lowland, one of the largest farmed vegetable regions in Central Europe. To accomplish this, a comprehensive analysis was conducted of the spatiotemporal variability of the date of the beginning of the growing season (BGS), the date of the end of the growing season (EGS), and the length of the growing season (GSL) for the period 1961–2011. In addition, an assessment was made of the potential changes in the dates of the BGS, EGS, and GSL for the Elbe River lowland, simulated using the regional climate models. Prospective areas for growing thermophilic vegetables in the study region were also determined.

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