The potential of agricultural management to alleviate extreme weather impacts on Swedish crop production

Climate change, stagnating crop yields and the increased demand for food pose challenges to future agriculture. Therefore, it is of great importance to assess the potential of agricultural management practices to mitigate the effects of climate change, and especially extreme weather events, on crop productivity. In this thesis, I assessed (1) the spatiotemporal patterns of crop species diversity and crop yields, (2) the vulnerability of crops to extreme weather and the importance of soil properties in mitigating such impacts, and (3) the influence of agricultural management on soil health indicators in Sweden. The analysis of historical crop data revealed an increase in crop diversity from the north to the south of Sweden, in line with increasing temperatures, implying that climatic conditions limit the diversity of crops that can be grown. A continued increase in cereal yields in southern Sweden since the 1960s, and an increase over time in crop diversity in several counties, indicate a potential also for future improvements. Crop yields were shown to be sensitive to excess water and favoured by increased temperatures in northern Sweden, while in southern Sweden, drought effects were more pronounced and increased temperatures had a negative impact on crop yields. Estimates based on satellite images showed a lower winter wheat growth rate and lower peak green leaf area index during drought compared to normal weather conditions. A high importance of plant available water during drought was shown by faster growth of winter wheat on fields with higher plant available water capacity, and by greater spring-sown cereal yield losses on lighter soils at the county level. On-farm analyses showed that higher crop rotational diversity, lower tillage intensity, higher use of organic fertilizers and less fungicide use were associated with improved soil health, and crop yields were influenced by organic matter content, wet aggregate stability and bulk density. Overall, this thesis suggests that targeted site- and crop adaptations are needed to mitigate the effects of extreme weather events on crop productivity.