Soil management to mitigate climate change-related precipitation eXtremes - SoilX

With climate change, both drought and heavy precipitation are becoming more frequent. The EJPSOIL project SoilX investigated the possibilities to mitigate impacts of such extremes on crop productivity through improved soil management practices. To do that, we applied a multidisciplinaryresearch framework. Three methodological approaches were applied to derive complementary findings on the possibilities to alleviate impacts of increasingly frequent precipitation extremes on cropping systems in Europe through adaptations in soil and crop management: (1) sampling and measurement campaigns in long-term field experiments (LTE’s) along a north-south gradient through Europe, (2) simulation experiments with an ensemble of four agro-hydrological models and the development of a new model for dynamically simulating soil structural changes, and finally (3) socio-economic interviews within regional farming communities.

From the compiled results of this project, we conclude that while soil structural improvements have potential to buffer the effects of short-term droughts on crop productivity according to hypothetical agrohydrological simulation experiments. However, the adaptation benefits realized in the contrasting field treatments of LTE’s studied in this project (i.e. organic amendments / no-till vs. conventional management) are likely to be small under current and future climatic conditions as measured differences in physical, mechanical and hydraulic properties were mostly small. This can be explained by the fact that treatments implemented in current LTE’s are often conservative (i.e. relatively small differences between contrasting treatments; often only single and not combined measures are tested). This finding calls for the introduction of new LTE treatments with greater emphasis on soil health and climate resilience. The need for more efficient management strategies to maintain and improve these soil functionalities is clearly highlighted by the results from model-based studies of climate change impacts in SoilX: climate warming contributed to the degradation of soil organic carbon resources, potentially also leading to a deterioration of the soils’ ability to infiltrate water and to retain water in the crop root zone.

Based on analyses of farmer interviews across different LTE regions in Europe, we can say that, since viewpoints on and priorities in the selection of soil management choices differ, diverse strategies to promote the uptake of soil management improvements are likely to be most successful: farmers with a strong intrinsic motivation to maintain and improve soil functionalities are most likely to respond positively to educational measures and can best be supported by regulatory frameworks supporting flexibility in the choice of measures. Farmers with a stronger focus on economic and production targets, however, may better be addressed by information campaigns highlighting possibilities for reducing production cost and increasing yield benefits in combination with regulatory frameworks that buffer against economic risks and possible additional costs.