EJPSOIL-SoilX: Final Project Report

With climate change, both drought and heavy precipitation are becoming more frequent. The 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 multi- and transdisciplinary research framework, where 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. During the harmonized field sampling campaign, contrasting treatments of organic inputs and tillage reduction were sampled in the selected LTE’s, both in topsoil and subsoil. A set of soil physical, mechanical and hydraulic properties were determined in lab analyses. The resulting dataset provides a valuable evidence base documenting soil structural differences in response to differences in management and pedo-climatic conditions within Europe. An R-Tool (SoilManageR) developed within the project allows for synthesizing management information into continuous management indicators, which can serve as predictor variables in advanced statistical analyses of measurement data such as collected within this project. Alongside these efforts, four agro-hydrological models (i.e. APEX, CANDY, DAISY, SWAP) were calibrated for a subset of LTE’s that represented a north-south climatic gradient and that had adequate amounts of reference data available. The calibrated models were applied to transient downscaled climate projections for the period 2021-2090 to evaluate the hypothetical adaptation benefits of soil structural improvements and to compare those potential benefits to the benefits that are achievable according to measured differences in soil hydraulic properties between contrasting treatments. These multi-model simulation experiments were complemented with the development of a new model (USSF) that allows for simulating the evolution of soil structural properties (which are assumed to be static in common agro-hydrological models) in response to climat