Two Dutch studies reveal the impact of weather on crop yields

The reduction in crop yields following extreme weather events such as drought and heavy rain has been accurately quantified for the first time. Depending on the type of crop and the phenomenon, the decrease ranges between 13 and 36%

by Matteo Cavallito

 

Extreme weather conditions, favoured by climate change, have an impact on crop yields. However, this is phenomenon is hard to quantify accurately. Providing some answers in this regard are two recent Dutch studies that involved several researchers monitoring local crops to determine more accurately the impact of events such as heat waves, persistent droughts, downpours and prolonged rainfall. Both investigations analyse the differences in production from year to year with more and less weather events per farm or field.

Drought and extreme rainfall explain yield variation almost entirely

The first study, recalls a Wageningen University statement, was sponsored by the Eindhoven University of Technology and focused on the potato harvest in several farm-managed plots between 2015 and 2020. The annual discrepancies between the yields of these plots were attributed to drought and heavy rainfall in 98% of the cases. Heavy rainfall reduced yields by 36%, drought lowered them by 13%.

“Yields highly varied among fields, just as the impact of these weather extremes on individual fields,” the study explains. “Identifying on which fields the impact is small provides direction for adaption strategies, which are urgently needed, considering the expected increased frequency of weather extremes according to the latest climate change scenarios”.

Potatoes and onions are more sensitive to weather events

Another research, involving scientists from Wageningen and Amsterdam Universities, compared the yields of ten different crops by examining the numbers in a farm database (the Dutch Farm Accountancy Data Network – FADN). The study also identified when the influence of weather phenomena peaked. Potatoes and onions were the most sensitive to extreme conditions.

Severe droughts show significant reductions in yield for all crops, and lead to yield reductions up to 24 percent  than average yields during the growing period,” the survey explained.

At the same time, “eight crops show significant reductions in yield due to severe water excess during the planting period, with yield reductions up to 18 percent.”

Soil can also be an important factor

The researchers also showed how irrigation, soil types and nutrients influence the impact of weather conditions on crops. ‘Soils such as sand or loess amplify the negative impact of drought on crop yield, while softening the impact of excessive precipitation,’ they explain. ‘Irrigation and to a lesser extent nutrient application are shown to moderately decrease the impact of extreme weather on crop yield.’

Climate favours extreme events

The results of the two studies provide further insight to the debate on the consequences of climate change in terms of the increasing incidence of extreme weather events. Last year, for example, the European Environment Agency (EEA) highlighted how floods and flooding – which mainly affect the north-western and central area of the continent – caused total damage of almost 258 billion euros between 1980 and 2021, with the impact, in terms of costs, increasing by an average of more than 2% each year.

Particularly serious is also the problem of drought events, which are now spread throughout the year across much of the region. Since 2018, in fact, extreme drought has affected more than 50 per cent of European soil, leading to a substantial decrease in harvests of crops such as maize, soya and olive oil. According to the EEA, the total annual economic losses expected across all economic sectors due to increased drought could rise from the current EUR 9 billion to up to EUR 45 billion by the end of the century.