Human activities frequently cause soil degradation, altering its multifunctionality and therefore its capacity to provide ecosystem services. Urban soil degradation notably results in high bulk densities due to trampling and machine traffic, loss of biodiversity, and lack of organic matter. The anthropic and ecological functions of soils can then be dysfunctional.

One of the major pillars in maintaining the balance of these ecosystems are the living organisms that populate them. Through their diverse lifestyles, soil fauna plays an active role in soil functions at different scales, through the prism of their functional traits.

We would like to promote the development of “pedofauna engineering” as a tool for the ecological reclamation of moderately degraded urban soils.

A conceptual framework has been created, linking functional traits of interest to soil fauna in the water cycle regulation function. We considered two sub-functions (infiltration and retention of water) and four soil processes in relation to them (creation of porosity, bioturbation, aggregation and organic matter fragmentation). To assess the success of reclamation through functional traits, it also appears that residual activities (e.g. burrows, biogenic aggregates) of soil organisms could be considered as relevant indicators of the ecological processes.

In order to test these postulates, we have selected a list of functional traits and attributes of interest in relation to soil compaction. Three species of organisms carrying the traits of interest (Lumbricus terrestris anecic worm, Eisenia fetida epigeal worm and Porcelio scaber isopod) were introduced into cosmes with urban park soil, compacted at 1, 1.3 and 1.45 g cm^-3.

Our results demonstrate that soil organisms with their related functional traits and attributes "Strong capacity to dig burrows", "Strong capacity to move in the soil" and "Body length between 12 and 22 cm", led to the creation of macroporosity and enhance the infiltration of water into the soil.

This conceptual framework is a work in progress but can surely provide a deeper and better understanding of the who and how of soil fauna's involvement in soil multifunctionality.

How to cite: Caron, L., Auclcerc, A., and Séré, G.: Reclamation of moderately degraded urban soils: creation of a cognitive model to link soil organisms’ functional traits to soil processes & functions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-274, https://doi.org/10.5194/egusphere-egu24-274, 2024.

A circular economy-based hybrid green roof system and green roof substrate was developed and tested to reduce the environmental impact of using natural resources such as water and components of substrates based on common primary materials. Two case studies and laboratory analysis were conducted to assess the performance of green roof substrate consisting of recycled crushed brick-based demolition waste and biochar from pyrolyzed sewage sludge. Substrates were tested for their hydro-physical properties such as maximum water capacity, retention curves, bulk density, grain size and pH and suitability for vegetation growth.

The purpose of first case study, which involved a green roof of 7×5 m², was to test two newly developed circular substrates in conditions of real green roof and to compare it with standard, commercially available, substrate. The new substrates differed in the amount of pyrolyzed sewage sludge biochar they contained (9.5 vol. % for one and none for the other), but both contained large proportion of crushed brick (37.5 vol. %). The impact of the pyrolyzed sewage sludge was the main focus of the evaluation. At the same time, the changes in hydrophysical characteristics (retention curves, hydraulic conductivity, grain size) over time were evaluated.

Second case study was conducted on two raised beds to test the newly developed substrates in the context of the novel solution combining an extensive green roof and rooftop constructed wetland that uses pre-treated grey water. This system is called Hybrid green roof (HGR). The viability of a hybrid green roof system that uses greywater for irrigation was evaluated by measuring water balance, testing water samples from different sections of the experimental beds, and monitoring temperature and water content along the height of the bed layers. The hybrid green roof system has a constructed wetland section that treats the greywater before it reaches the green roof.

Extensive green roof areas of experimental beds in both studies were planted with Sedum spp. Vegetation in both case studies is thriving. The biochar apparently provides nutrients for the plants, which results in more vigorous growth on the substrates containing biochar. In case of HGR, the nutrient (phosphorus and nitrogen) levels in the leachate from the test beds were relatively low, because the irrigation water goes directly to the drainage layer and does not wash out the nutrient rich substrate with biochar. The nutrient levels have only increased when there is rainfall. The recycled materials used to amend the substrates in this study had similar properties (maximum water capacity, bulk density, pH) to the commercial ones.

The results of the experiment show that hybrid green roof system can effectively reduce the nutrients concentrations in greywater and provide enough water for vegetation to grow, which can effectively reduce the urban heat island effect, cool the building underneath and even provide a source of good quality domestic water.

References:

• Petreje, et.al, Performance study of an innovative concept of hybrid constructed wetland extensive green roof with growing media amended with recycled materials, J. Environ. Manag. vol, 331 (2023), 10.1016/j.jenvman.2022.117151

How to cite: Petreje, M., Rybová, B., Hečková, P., and Sněhota, M.: Biodiverse dual-purpose wetland-green rooftop design based on recyclates, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7673, https://doi.org/10.5194/egusphere-egu24-7673, 2024.

Greater progress in the circular economy is expected to enable large cities to benefit more from ecosystem services. Reusing urban wastes can help reshape the urban environment and make the ecosystem more suitable for human use. Excavated material from building sites is one of the most abundant waste resources in megacities around the world, and some of this mineral waste can be used to create substrates, known as constructed Technosols, for the development of new green spaces. However, long-term studies are needed to determine the influence of the parent materials used in Technosol formulations on the community dynamics and trajectory of these new ecosystems. In this study, we assessed the impact of organic amendment on the evolution of constructed Technosols and the diversity of plant and soil macrofauna. A large-scale experiment was set up in 2013 in the suburban region of Paris, France, using excavated mineral materials with or without green waste compost (10%, v/v). Flora and macrofauna inventories were carried out over 10 years, as well as the physico-chemical properties of both Technosols. Plant biomass was consistently higher in the Technosols amended with compost, while plant diversity converged towards the same level. Soil macrofaunal diversity was negatively affected by the organic amendment initially, but after 10 years it was similar between the two soils and the neighboring soil used as reference. Macroorganisms abundance increased linearly during the first 4 years, especially for earthworms in Technosols with compost, but after 10 years it also decreased to a lower level compared to the neighboring reference soils. This study showed that Technosols constructed with mineral waste is a promising alternative to natural topsoils for green spaces. The addition of compost promoted plant growth throughout the experiment and had no impact on the diversity of plants and soil macrofauna in the long term.

How to cite: Araujo, J., Pando-Bahuon, A., and Lerch, T.: Plant and macrofauna communities dynamics in constructed Technosols over 10 years of experimentation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15077, https://doi.org/10.5194/egusphere-egu24-15077, 2024.

Arctic cities attract researchers’ interest by a unique combination of extreme climatic conditions and anthropogenic pressure. Urban soils are different from natural references in terms of the formation and functioning conditions. Urban soils are very heterogeneous ranging from semi-natural soils altered by: on the urbanization to artificial soil constructions composed from different materials and mixtures. These soil constructions are mainly created to support green infrastructure and can be considered a new ecological niche for microorganisms. This research aimed to identify the microbial features of urban soils and soil constructions in Arctic cities compared to the background soils.

The studies were carried out in the recreational zones of Kola region cities: Murmansk (68.58°N, 33.03°E), Monchegorsk (67.56°N, 32.52°E), and Apatity (67.33°N, 33.24°E), different in population, operating industry, and climate. Samples were taken from different soil horizons. Soil morphological (WRB classification), physicochemical properties (density; pH; C, N content (CN analyzer) etc., including heavy metals (ICP) were assessed. Microbiological indicators included the number of archaea, bacteria, fungi genes copies (PCR real time), functional diversity (MicroResp), microbial respiration (SIR).

Four main types of urban soil disturbance of the Kola Arctic have been revealed: slightly disturbed natural podzols and podburs; disturbed urban-stratified podzols and podburs; artificially created soil constructions with evidences of soil formation; artificially created soil constructions. Disturbed urban soil profiles contain a gray-humus urban stratified horizon with a low C content, but high N content and pH values. Urban soils in Murmansk and Monchegorsk had higher contents of C and N compared to those in Apatity. Whereas in terms of the content of heavy metals (Cu, Ni) in soils of Monchegorsk was higher compared to the other cities.

Microbial communities of soils and soil constructions in the Kola Аrctic cities responded differently to the influence of urban anthropogenic factors. The microbiological parameters were significantly influenced by age, land use history, the productivity and structure of vegetation, the degree of soil cover transformation, and the level of pollution. However, general patterns identified for the microbial communities were similar for all urban soils. There was a tendency towards an increase in the functional activity and diversity of microbial communities in artificially created soil constructions compared to natural urban soils and background references. In contrast, microbial respiration was higher in natural urban soils compared to soil constructions, but no general pattern was found across cities when compared to background soils. For example, in Murmansk and Monchegorsk the values were lower compared to background soils, whereas the opposite was shown for Apatity. The number of archaea genes copy was also higher in urban soils of Apatity compared to background soils. For most chemical and microbiological parameters of urban soils, the highest values were identified in the subsoil horizons, which may be due to the presence of buried horizons, various substrates, and artifacts.

Urban soils and soil constructions can provide a niche for microorganisms, but a complex of external factors affecting them in specific conditions plays a fundamental role.

Acknowledgements This research was supported by RSF #23-17-00118 and RUDN University Strategic Academic Leadership Program.

How to cite: Korneykova, M., Ivashchenko, K., Dolgikh, A., Kozlova, E., and Vasenev, V.: Microbial communities of soils and soil constructions in the Russian Arctic cities, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12915, https://doi.org/10.5194/egusphere-egu24-12915, 2024.

Calcareous grasslands are important biodiversity sites and among Europe’s most floristically rich habitats. These habitats are, however, threatened; many of the UK’s calcareous grasslands were lost to changing land use during the 20th century and pressure on the surviving (often fragmented) sites persists. Due to their ecological value and threatened status there is significant interest in restoring and creating new areas of calcareous grassland, and an increasing number of projects are working to restore or re-create these internationally important ecosystems.

A major calcareous grassland creation project in the Colne Valley in the UK is being undertaken as part of the Central 1 section of the HS2 (High Speed 2) Phase One rail development, delivered by the Align joint venture. This will form a large area (90 hectare) of calcareous grassland as part of a larger (127 hectare) mosaic habitat including wood pasture and wetlands on former low-grade arable land subsequently used for construction. This represents the largest single area of habitat creation along the HS2 route and will significantly contribute to the project’s commitment to deliver ‘No Net Loss’ in biodiversity. To create soil profiles suitable for supporting species-rich calcareous grassland by-products from the HS2 development will be used; this will combine sustainable re-use of construction materials with the development of novel ways to create or restore chalk grassland habitats. These materials include 2.6 M m³ of excavated chalk from 16 km of tunnel construction, crushed limestone and concrete from decommissioned compounds/haul roads, and subsoils (stripped during site clearance).

However, how to best create soil profiles to support calcareous grassland habitat creation, including the potential for re-use of construction by-products, is not well understood. Success depends on establishing the specialised soil physical, chemical and biological environment required to support the diverse calcareous grasslands plant communities, including suitable soil structure, infiltration capacity and nutrient levels. We have therefore tested constructed soil profiles using different configurations of site-derived materials / construction by-products, using numerous soil and plant metrics through a combination of controlled environment and field trials to assess their ability to support calcareous grassland creation.

Here we present results from the main large-scale, controlled-environment trial at Cranfield University, in which we tested four soil profile configurations and the effect of upper soil layer depth in large (1 m³) soil mesocosms. The development of calcareous grassland on these profiles was closely monitored over a six-month period, including above- and below-ground imaging to monitor sward and root development, alongside close monitoring of soil hydrology, microbial dynamics, nutrient cycling, and vegetation establishment and diversity. This included a simulated drought period to assess how soil profile configurations affected the developing grassland vegetation’s resistance to water stress. Our results provide a uniquely high-resolution examination of how constructed soil profiles can be used to support calcareous grassland establishment and how profile design affects the ability of restored grassland to withstand environmental stress. This will allow improvements in circular re-use of infrastructure construction by-products in habitat restoration and development of novel strategies for the (re-)creation of biodiverse habitats.

How to cite: McCloskey, C., Arpano, S., Rickson, J., Otten, W., Butler, R., Cantle, C., Hobbs, M., and Spears, C.: Large-scale mesocosm trials to optimise soil profiles for calcareous grassland habitat creation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12419, https://doi.org/10.5194/egusphere-egu24-12419, 2024.

Studying carbon stocks and fluxes in urban soils is becoming increasingly relevant, considering the continuous urbanization. Although they represent a relatively small area compared to forest or arable soils, urban soils could be considered as hot spots of anthropogenic carbon accumulation as it is estimated that they contain 3-5 times as much C per ha as natural soils (Vasenev & Kuzyakov, 2018). To date, few studies have investigated urban soil organic matter (SOM) quality and stability, i.e. its resistance to microbial decomposition. In this study, we evaluated the ability of thermogravimetry to predict SOM mineralization kinetic parameters at a regional scale. In order to achieve this, 180 soil samples were collected from two different land uses (lawns and woodlands) along a gradient of urban pressure (rural, suburban and urban areas) in the Paris region (France). We determined SOM mineralization kinetic parameters by measuring CO₂ emissions in long-term incubations and the thermal stability of SOM by thermogravimetry combined with differential scanning calorimetry and evolved gas analyzes (TG-DSC-EGA).  The SOM quality was also characterized by using Mid Infra-Red Spectrometry (MIRS). Overall, SOM thermal stability increased from the rural to the urban areas in both land-use types. Urban woodland soils had greater SOM thermal stability than urban lawns, probably because the woodlands are much older than the lawns and because of historical soil management legacy in Paris region. Significant and strong relationships were found between SOM thermal analysis indices (CO₂-T50 and energy density) and mineralization kinetics parameters (mineralizable C and turnover) measured in the laboratory. MIRS analyses revealed different chemical compositions depending on land use (higher aromaticity and condensation indices in lawns) and the urban gradient (lower polysaccharides content and aromaticity index in cities). This regional scale study suggests that 1) the thermal analysis of SOM, together with MIRS and soil physico-chemical measurements can be used to predict soil C mineralization potential and 2) SOM thermal stability and resistance to microbial mineralization are higher in urban soils, especially in woodlands.

How to cite: Lerch, T. Z., Foti, L., Nunan, N., Abbadie, L., Barot, S., Raynaud, X., and Lata, J.-C.: Soil organic matter quality along an urbanization gradient in Paris region, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11435, https://doi.org/10.5194/egusphere-egu24-11435, 2024.

Climate mitigation strategies and targeted carbon neutrality highlight the potential of soils as important terrestrial stocks of organic carbon (C). Although global soil models and datasets (e.g., HWSD, SoilGrids, or S-world) provide information on soil C stocks’ distribution around the world, they remain biased both geographically and regarding different land-use types. Geographically, soils of high latitudes are usually underrepresented in global datasets compared to temperate or tropical climates. As for land use, the major part of soil data comes from natural and agricultural areas, whereas soils of urban areas remain overlooked or completely ignored. The research aimed to fill this gap by exploring soil C stocks and factors driving their spatial variability in the Russian Arctic zone.

Soil survey was carried out in four cities of the Russian Arctic zone: Apatity (67 N; 33 E), Murmansk (68 N; 33 E), Vorkuta (67 N; 64 E), and Norilsk (69 N; 88 E). Soils in all the cities are exposed to severe climatic conditions combined with strong anthropogenic pressure from the coal and ore mining industries. Vorkuta and Norilsk are located in the permafrost zone, whereas the soils of Apatity and Murmansk do not have the permafrost layer. In each city, 30 to 100 locations were sampled, including topsoil (0-10) and subsoil (till 100 cm) layers. In the collected samples, total and organic carbon (SOC) was measured at the CN analyzer. Bulk density and rock fraction were measured to estimate C stocks. Soil microbial (basal) respiration was measured in standardized lab conditions, and the ratio between basal respiration and SOC contents was used to analyze biodegradation coefficients and half-life time. Spatial patterns of SOC distribution, including inter- and intra-city variability were analyzed by factorial ANOVA.

SOC stocks in Arctic cities were quite heterogeneous with a coefficient of variance of up to 100%. Topsoil SOC stocks were similar or even higher compared to the data reported for Russian cities in temperate climates (e.g., Moscow, Saint-Peterburg, or Ekaterinburg). Subsoil stocks were significantly lower compared to topsoil due to a gradual decrease of SOC contents with depth and a high amount of gravel and rock fragments. Elevation, vegetation, and proximity to the sources of anthropogenic disturbance were the main factors driving the intra-city variability. The difference between the cities depended on bioclimatic conditions including permafrost. On average SOC stocks in cities with permafrost were significantly higher compared to those in cities without the permafrost layers. One of the possible reasons can be the conservation of organic matter in subsoil horizons when the mineralization of organic matter is hampered by low temperatures and low microbial activity. Indirectly this statement is confirmed by higher half-life time values, although the difference was not always statistically significant.

Under climate changes the role of Arctic soils in carbon balance will further increase, therefore the research outcomes are highly relevant to develop the strategies of sustainable urban development in the region.

Acknowledgements This research was supported by RSF # 19-77-30012 and RUDN University Strategic Academic Leadership Program

How to cite: Vasenev, V., Korneykova, M., Dvornikov, Y., Sarzhanov, D., and Dolgikh, A.: Carbon stocks in soils of Artic cities: factors of inter- and intra-city variation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12429, https://doi.org/10.5194/egusphere-egu24-12429, 2024.

Soil artificialization goes together with increasing impermeable surface areas. The increased surface runoff and flood hazard is as a major threat in large cities. Moreover, runoff waters transport pollutants to downstream surface waters. A key strategy for sponge cities is to design permeable soils allowing for rain water infiltration, which should go together with runoff water depuration. High quality permeable soils are also necessary to secure and increase the tree cover in cities, which is highly recommended both to fight against heat waves, to provide a comfortable environment and contribute to urban biodiversity. We present a combined solution to these different goals.

To this end, a highly permeable and fertile growing media was designed based on recycled manure and partly pyrolyzed organic matter. The depuration properties of this substrate were quantified for road runoff pollutants (soluble and micro particle forms) and commonly used pesticides. About 100% removal of these pollutants were observed based on breakthrough experiments on Technosol columns, with outflow quality matching the Swiss Water Protection Agency requirements. The fertility of the substrate was assessed in greenhouse pot experiments. Faster plant growth than with conventional horticulture production methods was observed, though no fertilizer was applied to the growing media.

The growing media, named TP70, was then mixed with 70% stones (100-150 mm size) to obtain a Technosol (TP-P) with high bearing capacity such as required for urban use. An experimental 1m large tree plantation pit was built in Lausanne city using a 60 cm layer of the Technosol, covered with 20 cm of stone ballast. The pit was installed under the walkway of a 4% slope street. Runoff water was injected into the ballast via collectors and infiltrated into the Technosol porosity before drainage at the low-end of the pit.

The volume of the pit was designed to comply with the local regulation on runoff water regulation, namely offering a fast-drainage porosity volume larger than the amount 10-year return-time rainfall on the corresponding watershed, with full drainage in less than 4 hours. It was planted with trees and offered an available water volume corresponding to 9 days of maximum evapotranspiration in the experimented case. Both tree growth and hydrological functions of the pit offered high performance. Based on this first experiment, an eco-district was fully equipped with these impluvium pits, thus infiltrating all the rain waters on the district, and Lausanne city is now extending the technology to the city.

How to cite: Deeb, M., Palman, M., and Boivin, P.: Impluvium and multifunctional tree planting pits for clean-water sponge cities, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21344, https://doi.org/10.5194/egusphere-egu24-21344, 2024.

The French R&D MUSE project developed a methodology to map the potential multifunctionnality of unsealed soils based on existing data at national scale, in order to consider this information in urban planning. This method gives a partial idea of soil health. The data on rural areas allow mapping 4 ecological soil functions: potential of carbon storage, water storage, agronomic potential, and biodiversity reservoir. The lack of soil maps on urban area conducted to propose a simplified approach. The methodology was developed in collaboration with 3 pilot territories. The aim of this presentation is to establish feedback on the application of the methodology on various geographical and pedo-climatic contexts.

The analysis is carried out on more than 10 cases including Rennes Métropole, Ris-Orangis and Savoie Métropole, by checking the objectives of the application, the appropriation by operators and the adaptations proposed.

The feedback shows the ability to identify zones to be preserved, developed or disartificialised by crossing with other data. More detailed soil maps contribute to gain precision and are mandatory to design development projects. New methodological developments are proposed also to map soil multifunctionnality in urban areas. The integration of soil quality to reach the "no net land take" target is also in progress. It takes into account a moderation of the potential soil functions by knowledge on pollution risks and remediation projects.

The MUSE methodology is getting more and more applied in France, although its application needs some technical skills on soils and geomatics. In this frame, an automation script was developed to standardise the production of the 4 ecological soil function maps. It can be applied at various scales, according to the precision of the available data. The feedback underlines the need to wider characterise urban soil and to bank further the acquired data to improve the knowledge on urban soils. 

How to cite: Le Guern, C., Deslandes, B., Duvigneau, C., Basuyau, M., Lemot, A., Laroche, B., and Branchu, P.: Mapping soil multifunctionnality for urban planning and development: from research to "no net land take" , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6776, https://doi.org/10.5194/egusphere-egu24-6776, 2024.

Urban soils are pivotal to environmental health and urban ecosystems. They underpin green spaces, assist in pollution filtration, support biodiversity, and play a key role in water management. These functions are vital for sustainable urban development and the well-being of city residents. However, urban soil science faces significant challenges: a lack of comprehensive data, limited public awareness of soil's ecological roles, and difficulties in data collection within diverse, densely built urban environments. This presentation will demonstrate how citizen science initiatives can bridge these gaps in urban soil research. By leveraging community efforts, extensive soil data can be gathered across various urban landscapes. The goal is to engage and educate communities in soil data collection and monitoring, thereby enhancing public understanding and involvement in urban soil health. A multi-faceted approach, including interactive workshops, user-friendly mobile applications, and online resources, will be employed to educate and train citizens in soil science basics and data collection techniques. These strategies aim to simplify complex soil science concepts into engaging, easily understandable content, complemented by hands-on training in using soil testing kits and data recording tools. The integration of citizen science in urban soil research offers dual benefits: advancing soil science through expanded data collection and analysis, and enhancing public engagement in scientific endeavors. Citizen involvement in soil data collection increases the quantity and quality of soil data, covering a wider range of urban areas and incorporating diverse observations and localized knowledge from community members. The presentation will introduce the "Urban Soil Guide: Field and Lab Manual," a newly released comprehensive resource designed for both educational and general use. This manual provides practical guidance for understanding, testing, and managing urban soils, bridging the gap between theoretical knowledge and real-world application. Additionally, the role of social media in enhancing citizen science projects on urban soil research will be discussed. This includes strategies for community building, experience sharing, and the best platforms for data visualization and sharing results.

How to cite: Paltseva, A.: Empowering Communities: The Future of Urban Soil Science Through Citizen Science, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3217, https://doi.org/10.5194/egusphere-egu24-3217, 2024.