Preparing farmers for more extreme weather
Over the next few decades, farms will increasingly be affected by extreme weather. To help farmers prepare for this, Wageningen researchers have developed a stress test that combines knowledge about climate trends with data on crops. It reveals the impact climate change will have on agriculture.
“Farmers in general don’t pay all that much attention to climate change as they are more focused on the crops growing now and the coming harvest. But the very dry, hot summers of 2018 and 2019 and the drought now are raising awareness,” says researcher Daan Verstand of Wageningen University & Research. Agriculture will be increasingly affected by changing weather conditions — arable farming in particular. Verstand and his colleagues have developed a climate stress test to help farmers prepare for this. The test shows, for example, what the hotter, drier summers mean for farms. “Unlike the weather, which can be very variable, climate change takes place over decades. As a result, it seems a long way off still. Farmers tend to concentrate on the short term when considering their business anyway, looking 10 years ahead at most,” explains Verstand.
The climate stress test shows the consequences climate change will have for the farmer. WUR researcher Daan Verstand and agriculturist Edwin Michiels discuss the risks climate change creates for Michiels’ crops and how the stress test can help mitigate some of these risks.
Climate change demands a switch in people’s thinking, says Verstand. And that applies to the water boards as well as the farmers. “The Netherlands is geared to discharging water to avoid flooding. Farmers here have always focused on preventing damage due to too much water. Now we need to set up the land in such a way that we can store as much water as possible and use it efficiently, with farmers seeking to prevent damage from drought.”
The Wageningen researchers worked out the climate stress test in detail for two example farms: an arable farm in north Groningen with seed potatoes and an arable farm in the south-eastern Netherlands. They based the test on the climate scenarios of the Royal Netherlands Meteorological Institute (KNMI). These scenarios show that the Netherlands will become warmer. The summers will be drier, the winters milder and heavy downpours will occur throughout the year. It will therefore be wetter on balance. Sea levels will also rise. “The scenarios range from a modest impact to an extreme impact. We’ve allowed for that range in our calculations for the two farms,” says Verstand.
IMPACT ON CROPS IN 2050
- Lower yields due to more heatwaves. Bigger risk of second growth.
- Extreme downpours are more frequent, causing damage to the tubers due to flooding.
- Warmer winters make storage in air-cooled storehouses more difficult. That can increase losses and quality problems.
- The risk of night frosts when the plant emerges declines. Frost damage will become less common as a result. Damage from wet weather stays the same.
- Warm winters lead to more loss of sugar in the piles of beets.
- Extreme dry weather is more common, leading to premature ripening and lower yields.
- The risk of damage due to wet weather and fungal infection stays the same.
“The climate trends and their impact also differ depending on the region and the farm,” continues the researcher, who works at Wageningen Plant Research. The southern and eastern Netherlands will suffer far more from the extreme heat and dry conditions than the coastal areas, which will remain cooler but also face the problem of gradual salinization of the groundwater due to rising sea levels. Verstand: “And some farms are in a better starting position than others. The soil may be compacted due to heavy tractors, for example, which means it will be less permeable to water. As a result, water will not run off so well during a heavy downpour.” Compacted soil is not so good at retaining water and plants are unable to put down such deep roots, which in turn is a disadvantage during dry summers.
Next, the researchers examined what influence climate trends will have on the commonest crops. A previous study of 16 crops identified the type of weather that was most likely to cause problems for each crop. “We looked at which crops are grown a lot in the northern and south-eastern Netherlands; then we calculated what that would mean for an individual farm. In this way, we are trying to give as realistic a picture as possible,” explains Verstand. The climate stress test can show the implications of a particular allocation of the farmland, for example the effect when a farmer grows potatoes on half his land or on one fifth.
Potatoes and onions are quite vulnerable both to very wet weather and lengthy droughts and heatwaves. Up to half the potato harvest can be affected in a year with extreme weather. “That may mean lower yields or potatoes that are less marketable due to disease. Sugar beet and grains, on the other hand, are better able to cope with more erratic weather conditions.”
The potato plant is a crop that is vulnerable to extreme weather. There is a risk of the harvest failing. Photo: Shutterstock
Milder winters also mean fewer of the overnight frosts that help kill off diseases and weeds. Verstand expects that farmers will therefore need to do more to tackle diseases, pests and weeds. However, he also sees upsides. “Young sugar beet plants are vulnerable to night frosts in April or May, so in future there will be less risk of them suffering frost damage or dying.”
Striking a chord
Since the start of the project to develop a climate stress test in spring 2019, the researchers have organized several workshops, including ones with farmers in the south-eastern Netherlands. “We discussed the consequences of the warmer weather and water shortages, along with possible solutions such as collecting water during wet periods and avoiding soil compacting. These were positive exchanges that really struck a chord with people. Farmers are starting to join up the dots. They realize that what counts as extreme weather today could be normal in the future and so they start thinking about solutions. The need to adapt to climate change is becoming increasingly urgent but people are still figuring out what would be the best approach.”
IMPACT ON CROPS IN 2050
- Warm wet weather becomes more likely in the late summer, which increases the risk of disease.
- The risk of damage due to drought could increase by a factor of two or more.
- Lengthy wet periods and extreme downpours become more common. That increases the risk of flooding and rot.
- More quality problems due to hot weather and droughts.
The researchers want to extend the climate stress test by adding five examples from other Dutch regions. Verstand would also like to incorporate potential mitigation measures into the stress test in future. “Another study is currently being carried out on the effect of various measures on the risks. But it is difficult to make the transition from individual measures to a cohesive farm setup.”
Ideally, the researcher would like to make the climate stress test suitable for use by individual farms. “It would be great if each farmer could input data about their location and farm in an app or website and then see what effect climate change will have on their farm. Who knows, perhaps we will get there one day.”