Introduction

The occurrence of extreme weather events, such as high temperatures, drought in summer and floods in winter, will increase almost everywhere in the EU and guidance on management practices to help farmers adapt to these situations is necessary. Soil management and cropping systems to enhance organic matter contents and life in soil have often been proposed as a key way to support the sustainable adaptation of EU agriculture to climate change (EEA Signals 2019-Land and Soil in Europe).

The ecosystem services a soil can deliver and therefore its potential as climate adaptation tool, depend profoundly on its structure Powlson , 2011 . This structure, or the physical arrangement of the soil pore space, influences transport of water and nutrients, as well as life in soil (e.g. root growth, faunal and microbial activity). Soil structure is constantly evolving, driven by changes in exogeneous factors and mediated by various biological and physical processes (Figure 1) that span time scales ranging from seconds to centuries Meurer , 2020. Because of the diversity of structure-forming processes and agents, soil is structured across a wide range of scales. In addition, most long-term field trials measure surrogate variables (or proxies) for soil structure, such as infiltration rates or soil hydraulic properties (water retention, hydraulic conductivity at and near saturation).

Although there is a wealth of knowledge available on the individual processes driving soil structure, the combined effects of our soil management practices and cropping systems and completely new climates on soil hydrological and biological functioning is still poorly understood. We lack systematic knowledge of the speed, magnitude and reversibility of changes in soil structure. We also lack quantitative tools to predict these changes as the development of mechanistic soil-crop models that account for soil structure dynamics is still in its infancy Vogel , 2018. As ultimately, crop growth depends on the combined effects of different climatic drivers, it is also important to assess the impact of precipitation, partial pressure of CO₂ in the air and temperature on the processes driving soil structure dynamics and uptake of water and nutrients by plants. This can be done using the results of manipulated environment experiments Rineau , 2019.

CLIMASOMA contributes to a long-term alignment of research strategies connecting agricultural management, soil quality and climate adaptation potential through its summary of the published literature and identification of knowledge gaps and research opportunities. The shared vision on this topic will result in clear additions to EJP Soil’s roadmap for soil research.

The aim of this project was threefold:

1. To synthesize and quantify the role of soil management on the hydrological soil functions and the adaptive capacity and resilience of crop production to climate change.
2. To identify approaches using soil structure dynamics and its driving processes in soil-crop modelling.
3. To identify future research needs to deepen our understanding of the implementation and impact of soil management on soil hydrological and biological functioning to foster adaptation to climate change.

CLIMASOMA realized this by (i) collecting relevant literature, databases and modelling approaches covering bio-physical, agronomic and socio-economic & policy factors of climate change adaptation through their effect on soil structure as driver of hydrological and biological processes, (ii) structuring the data from existing work in an open knowledge library (https://www.bonares.de/knowledgelibrary/, “KLIB“) and an open new database on unsaturated hydraulic conductivity (OTIM) and (iii) analysing this knowledge library qualitatively and the database quantitatively to uncover relationships and their interplay, causalities and knowledge gaps. We also explored the potential of text mining techniques (natural language processing (NLP)) to gain more control over the vast amounts of literature available.