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The relatively poor simulation of the below-ground processes is a severe drawback for many ecosystem models, especially when predicting responses to climate change and management. For a meaningful estimation of ecosystem production and the cycling of water, energy, nutrients and carbon, the integration of soil processes and the exchanges at the surface is crucial. It is increasingly recognized that soil biota play an important role in soil organic carbon and nutrient cycling, shaping soil structure and hydrological properties through their activity, and in water and nutrient uptake by plants through mycorrhizal processes. In this article, we review the main soil biological actors (microbiota, fauna and roots) and their effects on soil functioning. We review to what extent they have been included in soil models and propose which of them could be included in ecosystem models. We show that the model representation of the soil food web, the impact of soil ecosystem engineers on soil structure and the related effects on hydrology and soil organic matter (SOM) stabilization are key issues in improving ecosystem-scale soil representation in models. Finally, we describe a new core model concept (KEYLINK) that integrates insights from SOM models, structural models and food web models to simulate the living soil at an ecosystem scale. Copyright 2020 Deckmyn et al.

Soil organisms, including earthworms, are a key component of terrestrial ecosystems. However, little is known about their diversity, their distribution, and the threats affecting them. We compiled a global dataset of sampled earthworm communities from 6928 sites in 57 countries as a basis for predicting patterns in earthworm diversity, abundance, and biomass. We found that local species richness and abundance typically peaked at higher latitudes, displaying patterns opposite to those observed in aboveground organisms. However, high species dissimilarity across tropical locations may cause diversity across the entirety of the tropics to be higher than elsewhere. Climate variables were found to be more important in shaping earthworm communities than soil properties or habitat cover. These findings suggest that climate change may have serious implications for earthworm communities and for the functions they provide., Unión Europea. Horizonte 2020, Unión Europea. FP7, Ministerio de Ciencia e Innovación (MICCIN), sDiv [Synthesis Centre of the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Academy of Finland, Natural Sciences and Engineering Research Council of Canada, DOB Ecology, TULIP Laboratory of Excellence, Russian Foundation for Basic Research, Tarbiat Modares University, Aurora Organic Dairy, UGC (NERO), Slovak Research and Development Agency, Science for Global Development through Wageningen University, Norman Borlaug LEAP Programme and International Atomic Energy Agency (IAEA), São Paulo Research Foundation (FAPESP), Oklahoma Agricultural Experiment Station, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Royal Canadian Geographical Society, Environmental Protection Agency (Ireland), University of Hawai‘i at Mānoa, U.S. Department of the Navy, Commander Pacific Fleet, Science and Engineering Research Board, Department of Science and Technology, New Delhi, India, Strategic Environmental Research and Development Program (SERDP) of the U.S. Department of Defense, Maranhão State Research Foundation (FAPEMA), Coordination for the Improvement of Higher Education Personnel (CAPES), Ministry of Education, Youth and Sports of the Czech Republic, Colorado Wheat Research Foundation; Zone Atelier Alpes, French National Research Agency, Austrian Science Fund, Landwirtschaftliche Rentenbank Frankfurt am Main, Welsh Government and the European Agricultural Fund for Rural Development, SÉPAQ, Ministry of Agriculture and Forestry of Finland, Science Foundation Ireland, University of Toronto (Faculty of Forestry), Haliburton Forest and Wildlife Reserve, NKU College of Arts and Sciences, Österreichische Forschungsförderungsgesellschaft, Mountain Agriculture Research Unit of the University of Innsbruck, Higher Education Commission of Pakistan, Kerala Forest Research Institute, Peechi, Kerala, UNEP/GEF/TSBF-CIAT, GRDC, AWI, LWRRDC, DRDC, National Scientific and Technical Research Council (CONICET), National Agency of Scientific and Technological Promotion (FONCyT), Universidad Nacional de Luján/FONCyT, Fonds de recherche sur la nature et les technologies du Québec, Deutsche Forschungsgemeinschaft, CONACYT, NSF, Institute for Environmental Science and Policy at the University of Illinois at Chicago, Dean’s Scholar Program at UIC, Garden Club of America Zone VI Fellowship in Urban Forestry from the Casey Tree Endowment Fund, J. E. Weaver Competitive Grant from the Nebraska Chapter of The Nature Conservancy, College of Liberal Arts and Sciences at DePaul University, Elmore Hadley Award for Research in Ecology and Evolution from the UIC Dept. of Biological Sciences, Comisión Interministerial de Ciencia y Tecnología (CICYT), Yokohama National University, MEXT KAKENHI, Japan Society for the Promotion of Science KAKENHI, ADEME, Syngenta Philippines, UPSTREAM, LTSER, Comisión Europea, National Science and Technology Base Resource Survey Project of China, McKnight Foundation, Program of Fundamental Researches of Presidium of Russian Academy of Sciences, Brazilian National Council of Research CNPq, French Ministry of Foreign and European Affairs, Depto. de Biodiversidad, Ecología y Evolución, Fac. de Ciencias Biológicas, TRUE, pub

The kinetics of glauconite dissolution have been determined in the pH range 2–10 (T = 25°C) using flow-batch reactor experiments. Besides the kinetic characteristics, the structural and textural aspects which could influence its long-term reactivity have also been characterized by means of X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM) and BET surface area measurements. The results from these analyses showed that glauconite follows a dual dissolution pathway which is pH-dependent, being more stable at neutral or slightly alkaline pH values. Under acidic conditions, glauconite is slightly more soluble than other ubiquitous silicates present in the marine sediments. The dissolution mechanism is incongruent at very acid pH values and tends to be congruent for intermediate and neutral ones. In addition, the results from the structural analyses suggest that the dissolution is a two-step process: the first one involves the disorder of the octahedral and tetrahedral layers, probably following a turbostratic mechanism which is evident in the XRD spectra as selective broadening of several reflections. In the second step, the dissolution of the cations from interlayer positions takes place and leads to the formation of an amorphous residue which acts as a passivating layer and reduces the reactive surface considerably. The influence of these aspects on CO2 capture via carbonation reactions is discussed.

In this study, we measured the incorporation of recent photosynthate-C inputs into active rhizosphere fauna (earthworms, enchytraeids, mites and collembolans) in an upland grassland soil under natural environmental conditions. This was achieved by means of a 13CO2 pulse-chase experiment made during the growing season, followed by a 20-day dynamic sampling of soil fauna for 12C/13C analysis by IRMS. The effect of post-13C labelling defoliation (cutting) on fauna 12C/13C ratios was also examined. Results showed that earthworms made up over 93% of the extracted fauna biomass, while mites, collembolans and enchytraeids together accounted for less than 7%. All fauna groups showed evidence of tracer 13C in their tissues within a week of 13CO2 pulse labelling in both control and cut treatments. Cutting significantly increased the amount of tracer 13C entering the organisms (P=0.0002). Similarly, the fauna group also had a significant effect (P=0.0001). Time did not have any effect on fauna 13C content between groups as differences were only significant at the last sampling occasion. The interaction time×animal group, however, had a significant effect (P=0.0054). Collembolans accounted for most of the tracer 13C measured within the fauna biomass, i.e. mean±standard deviation of 44.78±12.75% and 44.29±14.69% of fauna 13C in control and cut treatments, respectively. Mites and earthworms contained between 22.13% and 28.45%, and enchytraeids less than 6% of the tracer 13C. We conclude that, during the growing season, there was a rapid incorporation of recent photosynthate-C into rhizosphere mesofauna. This carbon transfer was most significantly increased by defoliation in mites and collembolans (P<0.01). These results provide evidence that soil foodweb carbon dynamics are not solely underpinned by detrital decomposition but are also affected by short-term plant rhizodeposition patterns.

Three species of earthworm, Lumbricus terrestris L., Aporrectodea longa (Ude) and Allolobophora chlorotica (Savigny), were offered a choice of mixtures of soil and small wheat straw fragments which had been inoculated individually with six saprotrophic fungi. All earthworm species showed preferences between the six fungal species offered. Early straw decomposers, capable of utilizing water-soluble sugars and cellulose, were preferred in most cases to the lignin-decomposing fungi characteristic of the later stages of decomposition. The removal of fungal-inoculated straw pieces from the soil surface by L. terrestris followed the same pattern. The palatability of two wheat pathogens to L. terrestris was found to be similar to that of the preferred saprotroph. The implications of these findings for fungal abundance and dispersal in wheat fields are discussed.