In north-western Europe, agricultural production is largely determined by the variability of weather conditions and how farmers deal with them. Managing weather-related risks includes on-farm measures and strategies to share the risk. With climate change, adverse weather conditions are projected to increase in magnitude, frequency, and duration – hence the need to improve on-farm measures and provide more flexible insurance schemes.
Long-term time series analyses of annual mean temperature in north-western Europe reveals that a warmer period started abruptly after 1988. Comparing the period before and after 1988 shows that key crop stages are occurring 3-4 days per decade earlier (Figure 1). Although there was a severe drought and heat wave during 2003 in north-western Europe, crop statistics clearly showed that there was little effect on winter cereal yields in Belgium and Northern France.
This suggests that only adverse weather conditions during sensitive stages result in low yields. During the past decade, a great deal of research has been devoted to the occurrence and timing of extreme weather events and the relationship with crop yields and crop quality.
Weather conditions vary significantly between years, crops, and growth stages. The temporal overlap between weather conditions and crop stages can be determined using a model that couples crop development with the soil-water balance and crop growth.
This methodology helped us to redefine 20-year return values for frost, waterlogging, heat stress, and drought in both winter and summer crops. This approach can be used to defining more flexible insurance schemes.
The approach of combining physically based crop modeling with statistical methods shows that water (drought and waterlogging) and temperature (frost and heat) stress result in low arable yields when they occur either in concatenation or in combination with adverse weather conditions such as low radiation during the growing season.
This approach can be extended to other regions and can help establish weather- and crop-based agricultural insurance.
These findings are described in the article entitled Weather related risks in Belgian arable agriculture, recently published in the journal Agricultural Systems. This work was conducted by Anne Gobin from the Flemish Institute for Technological Research.