The impacts of key adverse weather events on the field‐grown vegetable yield variability in the Czech Republic from 1961 to 2014

Abstract

ABSTRACTThe 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.