Anthropogenic impact on ecosystems has a crucial effect on soil properties, functions and ecosystem services including biodiversity and carbon sequestration. Arable soils and soils of urban, industrial, traffic, mining and military areas (SUITMAs) are exposed to anthropogenic disturbance and transformation. Biological capacity, greenhouse gases’ emission and carbon stocks of anthropogenically-transformed soils differ considerably from natural soils but so far remain overlooked. Negative anthropogenic impacts (e.g., soil sealing, construction, and contamination) can alter and deplete soil functions and ecosystem services, whereas best-management practices (e.g., no till, crop rotation, soil engineering) can enhance the value of anthropogenically-transformed soils. Further, the development of diversified cropping systems (rotations, multiple cropping and intercrops for food, feed and industrial products) under low-input practices for conventional and organic systems could increase land productivity and crops quality, and reduce machinery, fertilizers, pesticides, energy and water demands.
The session will focus on biological diversity and capacity, carbon stocks and fluxes of anthropogenically-transformed soils at the local, regional and global scales. It will promote research achievements addressing advanced and integrated methods in monitoring and assessment of plant and microbial diversity, chemical and physical properties, biological capacity and soil health to support best management practices and nature-based solutions. Indicators and parameters of soil-plant interactions, effectiveness of crops and soil management practices will also be discussed during the session. The session format will promote knowledge and information exchange about soil micro- and mesofauna, community succession, and biochemical processes following the development and evolution of SUITMAs and arable soils. A comprehensive analysis and original case studies presenting contribution of soil biota to the ecosystem services provided by agricultural lands and urban green infrastructure, would greatly contribute to this session. Spatial variability and temporal dynamics in properties, functions and ecosystem services of arable soils and SUITMAs in the context of global changes will be discussed regarding the perspectives of sustainable development of urban and rural areas.

The rhizosphere is regarded as the soil compartment with the highest level of nutrient flux through a multitude of interactions between plants, soil, and (micro)biota. Roots and associated (micro)organisms interact with heterogeneous soil environments that provide habitats for biota on various scales. High metabolic activity and nutrient cycling can be observed from single root tips to whole root systems which makes the rhizosphere of central importance for ecosystem functioning.
The main knowledge-gaps in rhizosphere research are related to the difficulty in mechanistically linking the physical, chemical and biological processes, taking place at different scales (nm to cm) in the rhizosphere and to the challenge of upscaling these processes to the scale of the root system and the soil profile. The key for overcoming these knowledge gaps is to understand rates of matter flux, and to link the spatial arrangement of the different interconnected components of the rhizosphere with their temporal dynamics. This requires concerted efforts to combine methods from different disciplines like plant genomics, imaging, soil physics, chemistry and microbiology.
We welcome experimental and modelling studies on rhizosphere functioning that aim at revealing spatial gradients of e.g. functional biodiversity of microorganisms, uptake and release patterns by roots, soil structure modification by root growth (and vice versa) as well as feedbacks between those processes in order to improve our mechanistic understanding of emerging properties like water acquisition, nutrient cycling, plant health, soil structure development and feedbacks among them.

This PICO session will gather most recent tools and experimental strategies to shed light on (i) the role of the soil physical structure on the soil biota on the one hand and (ii) focus on soil biota shaping soil physical structure and functionality on the other hand. Case studies linking soil structure to soil biota with respect to soil functions and the processing of organic matter will be described using novel techniques and approaches. Materials such as manufactured aggregates or synthetic polymers (Soil Chips) are used to re-create soil structure with defined characteristics and open unprecedented experimental possibilities in soil physics-soil ecology boundary line. Under natural conditions, cutting-edge imaging techniques, such as µCT (X-rays), neutron radiography and Nano-SIMS allow to finely characterise soil structures and link it to soil biological activity (isotopes, PLFA). Vice-versa, soil biota shapes soil physical structure, in particular through extracellular polymeric substances (EPS), excreted mainly by bacteria, fungi and plants. EPS are assumed to play a role in particle cohesion and thus in soil physical structure, besides the several functions they promote in microbial life, e.g. adhesion to surfaces; reduction of cellular desiccation; tolerance of excessive changes in temperature, pH, salinity. If and how this can be transferred to soil functionality such as soil hydrologic properties and under which condition significant EPS will be produced is still a pending question. The overview provided here mostly focus on microorganisms and microfauna, with some case studies reporting the effect of roots or larger organisms, such as earthworms. The PICO format will convey demonstration of new tools and approaches to study the soil physics - soil ecology interface.
The Keynote speaker of this session is Dr. Edith Hammer (Lund University, Sweden).

Microbial hotspots in soils such as the rhizosphere, detritusphere, biopores, hyphasphere, aggregate surfaces, charsphere, etc., are characterized by high activity and fast rates of such process as soil organic matter (SOM) turnover, nutrient mobilization, litter decomposition, respiration, organic matter stabilization, greenhouse gas emission, acidification, etc. The turnover intensity of microbial biomass and SOM as well as nutrient cycling in such hotspots is at least one order of magnitude higher than in the bulk soil.
This session invites contributions to: 1) Various aspects of microbial activity, interactions, communities composition and distribution in hotspots; 2) Factors influencing (micro)biological nutrient (re)cycling including biotic and abiotic controls; 3) New developments to assess and simulate the crucial microbial mechanisms that underpin biogeochemical processes in hotspots (e.g. new approaches and imaging methods); and 4) Combination of experimental, theoretical and modelling approaches to predict the fate and functions of microorganisms in hotspots.

Terrestrial ecosystems across the globe are being exposed to elevated atmospheric CO2, causing increase in temperatures and more frequent and intense drought and rainfall events. These changes have strong implications for biogeochemical cycling and the functioning of terrestrial ecosystems. Understanding the mechanisms controlling the response of plants and soil biota to climate change is therefore critical to predict potential feedbacks of terrestrial ecosystems to future climate scenarios.

The aim of this session is to bridge the knowledge of different disciplines to elucidate the multi-scale mechanisms and feedbacks underpinning the biogeochemical response to climate change, with emphasis on warming, drought and drying-rewetting dynamics. This session will give a broad overview of empirical and modelling studies across different scales, considering how climate change affects terrestrial biogeochemistry and the interactions between soil, microorganisms, plants and fauna. Attention will be given to the resistance or adaptation mechanisms of plants and soil biota during single or repeated environmental disturbances, as well as to the resilience and the associated temporal recovery dynamics after a disturbance. We will bring together researchers from different environments and create a discussion platform to review the current state-of-the-art, identify knowledge gaps, share ideas, and tackle new challenges in the field.

Soil biodiversity and the provision of services that are beneficial to the productivity and sustainability of land use systems occur at different spatio-temporal scales and depend on environmental factors. Biogeographic mapping and land use systems affect soil biodiversity and how soil biodiversity (i.e. the performance of functional groups) feeds back to soil functions and ecosystem services. Soil organisms are at the center of soil organic matter formation and degradation. They transfer plant-derived carbon into stabile soil carbon pools, which has been termed the soil-carbon-pump. Carbon use efficiency (CUE), the efficiency of the pump as well as growth and turnover, the pump’s throughput, are increasingly used to describe soil organic matter formation. Since CUE and growth are influenced by numerous biotic and abiotic factors and interactions, a wide range of approaches has been used to get a grip on the controls of the soil-carbon-pump.
In this session, we welcome studies on spatio-temporal aspects of soil biodiversity as well as the role of soil organisms in the carbon cycle, and especially on soil microbial physiology, CUE, growth and turnover. We encourage contributions that examine soil biodiversity on all scales and trophic levels, CUE, microbial growth and turnover in models, lab and field experiments, and in ecological conceptual frameworks.

Public information:
Soil biodiversity and the provision of services that are beneficial to the productivity and sustainability of land use systems occur at different spatio-temporal scales and depend on environmental factors. Biogeographic mapping and land use systems affect soil biodiversity and how soil biodiversity (i.e. the performance of functional groups) feeds back to soil functions and ecosystem services. Soil organisms are at the center of soil organic matter formation and degradation. They transfer plant-derived carbon into stabile soil carbon pools, which has been termed the soil-carbon-pump. Carbon use efficiency (CUE), the efficiency of the pump as well as growth and turnover, the pump’s throughput, are increasingly used to describe soil organic matter formation. Since CUE and growth are influenced by numerous biotic and abiotic factors and interactions, a wide range of approaches has been used to get a grip on the controls of the soil-carbon-pump.
In this session, we will discuss spatio-temporal aspects of soil biodiversity as well as the role of soil organisms in the carbon cycle, and especially on soil microbial physiology, CUE, growth and turnover.
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