Oxytetracycline (OTC) is one of the popular antibiotics accumulated in soils and groundwater, posing harmful effects on ecological systems and human health. The objective of this work is to examine the feasibility of OTC degradation using a new catalyst, oxygen-doped graphitic carbon nitride (O-gC₃N) for in-situ oxidation remediation. In-situ oxidation system was simulated with column experiments to investigate the performance of PMS activation and OCT removal in saturated porous media. Numerical modeling as HYDRUS 1D was used to analyze OTC's transport behaviors in saturated porous media. The results show that OTC transport in saturated porous media is non-equilibrium. O-gC₃N can efficiently activate PMS to degrade OTC and the increase of PMS and O-gC₃N can enhance OTC removal. A wide pH range is beneficial for OTC degradation in saturated porous media. EBCT significantly affects OTC degradation and the optimal velocity was 0.4 cm/min. The findings of this work suggest that O-gC₃N catalyst can effectively be utilized for the in-situ oxidation of organic pollutants in contaminated sites.

How to cite: Ko, S., Nguyen, T. T., and Kim, D.: Degradation of oxytetracycline in saturated porous media by in-situ chemical oxidation using oxygen-doped graphitic carbon nitride and peroxymonosulfate (PMS), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1305, https://doi.org/10.5194/egusphere-egu24-1305, 2024.

The water leachable amounts of heavy metals including arsenic (As), lead (Pb), and cadmium (Cd) can be found in relatively higher concentrations in surplus soils from construction activities. There is a potential risk to human health and negative impacts on the soil and water environment. One of the cost-effective and efficient strategies for remediation techniques is the immobilization of heavy metals based on natural and artificial materials. The objective of this study is therefore to use five waste and recycled materials such as fly ash and recycled concrete. It tries to achieve simultaneous immobilization of several heavy metals in naturally contaminated soils. Two representative natural soils containing relatively higher concentrations of water leachable As, Pb, and Cd were selected and tested for a simple batch immobilization experiment in the laboratory. The weight percent of each waste and recycled material added to each soil was 2.5%, 5%, and 10%. After 24 hours of curing at 20^oC, 10 times the volume of ultrapure water was added and shaken for 6 hours. The supernatants were filtered through a 0.45 µm filter and the concentrations of heavy metals were measured by ICP-MS. Generally, the immobilization rate of As, Pb, and Cd increased with increasing additive weight of waste and recycled materials. Recycled concrete especially demonstrated simultaneous immobilization of these heavy metals above with its addition of 2.5% to 5%, suggesting a better immobilization performance compared to other waste and recycled materials.

How to cite: Saito, T., Kawabe, Y., and Watanabe, N.: Simultaneous immobilization of several heavy metals in naturally contaminated soils using waste and recycled materials, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8557, https://doi.org/10.5194/egusphere-egu24-8557, 2024.

The challenge of restoring degraded landscapes or ecosystems and recultivating them in a way that maximizes the multifunctionality of the artificial soil depends on the extent of soil degradation and its causes. The process of land restoration is expensive, time-consuming and requires careful planning and collaboration between different stakeholders and sectors. In densely populated regions such as Central Europe, there are two major types of artificial soil ecosystems: restoration of landfills or mining pits and urban green infrastructure (e.g. urban tree sites, stormwater retention areas). To compensate for the increasing scarcity of arable land, soils with unfavorable properties must be improved and degraded land must be rehabilitated in order to fulfill soil functions and promote agricultural production.

Engineered soils offer a solution for construction the top layer that allows the restored ecosystem to function. Such soils are made from excavated material and other mineral or organic waste and are composed to provide suitable conditions for plant growth and other ecosystem services provided by the soil.

As the need for green spaces in urban areas is also increasing, e.g. to adapt and mitigate the urban heat island effect, soil is needed as a habitat for plants and engineered soil mixtures are required depending on the target location and purpose. Soil mixtures with suitable chemical, physical, biological and geotechnical properties (i.e. physical structure) are needed, which are suitable for the restoration of topsoil for various purposes (e.g. mining reclamation, urban greening) and can be used for the near-natural composition of functional soil layers suitable for reclamation and plant growth. Soil structural properties such as infiltration rate, pore volume and water retention capacity are crucial for the functionality of restored soils in the water cycle, especially in view of the increasing challenges posed by ongoing climate change.

The aim of this study is to provide a comprehensive overview of the experiences made at research sites in Slovenia and Austria with the application of engineered soils for the restoration of degraded areas. The focus of the contribution is set on different regulatory requirements and methods to ensure the proposed soil hydrological functionality.

This research has been financed by ARIS BI-AT-22-23-019, LIFE20 IPE/SI/000021 ReStart and OEAD WTZ SI 01/2023.

How to cite: Zupanc, V., Zeiser, A., Rath, S., Strauss, P., Grčman, H., Zupan, M., Gantar, A., Pečan, U., Pirnat, M., and Weninger, T.: Soil restoration for urban areas: Exploring water-related ecosystem services and hydrological functionality , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11896, https://doi.org/10.5194/egusphere-egu24-11896, 2024.

Ionophore antibiotics, such as narasin and monensin, are widely used in the poultry industry and are the only type of antibiotics that the EU allows to incorporate as feed additives, and use them without veterinary prescription, with the consequent risk of favouring antibiotic bacterial resistance. In the case of the narasin it has been proved that, in poultry, the use of this antibiotic may increase the number of enterococci bacteria that are resistant to the human antibiotic vancomycin; meanwhile ruminal Prevotella strains might become resistant to monensin. Furthermore, these drugs are very toxic to humans. For these reasons, the entrance of antibiotics in the environment due to the use of manure and slurry as fertilizers in agricultural soils is an important environmental problem and a risk for human and animal health. The soil can adsorb these antibiotics and prevent their entry into the food chain, but sometimes its retention capacity is low and could be improved by incorporating residues that can act as contaminant adsorbents. The objective of this study was to analyse the adsorption and desorption processes in three soils and four different biadsorbents for narasin and monensin. The study was perform using one forest soil under Eucalyptus and two crop soils, and four different by-products as bioadsorbents (wood ash, pine bark, mussel shell and olive residue). Different concentration (5, 10, 20, 50, 100, 200, 400, 800, 1000 µmol L^-1) of both antibiotics were added to both soils and bioadsorbents and adsorption / desorption test were performed by means of HPLC.

The results showed that the soils adsorbed 100% of the added monensin at low concentrations, and this percentage decrease to 80-86% when 1000 µmol L^-1 of antibiotic were added. The adsorption was irreversible for the low concentrations and the desorption increase up to a maximum of 1-12% for the higher ones. Regarding the bioadsorbents, for the higher concentration of monensin added, the olive residue and wood ash adsorbed 99 and 98% of the antibiotic, respectively. On the other hand, the pine bark and mussel shell adsorbed a maximum of 64 and 48%, respectively, for the lower concentrations and these percentages decreased to 25 and 34% when 1000 µmol L^-1 were added, with generally small desorption values. For the antibiotic narasin, the soils adsorbed 100% of the added antibiotic, and only decreases to 99% when 1000 µmol L^-1 are added; and they desorbed less than 1% of the absorbed at that concentration. Regarding the bioadsorbents, the olive residue adsorbs irreversibly 100% of the narasin added for all concentrations, meanwhile the mussel shell, wood ash and pine bark adsorbed 86, 89 and 96%, respectively, for the highest narasin concentration, with no desorption for any antibiotic concentration.

The soils, olive residue and wood ash were good bioadsorbents for both antibiotics, due to their high adsorption capacity, irreversible in most cases. The pine bark and mussel shell were as well good bioadsorbents for naransin, but that´s not the case for monensin.  

How to cite: Alvarez-Rodríguez, E., Cela-Dablanca, R., Barreiro, A., Míguez-González, A., Nuñez-Delgado, A., and Fernández-Sanjujo, M. J.: Adsorption and desorption of the ionophore antibiotics narasin and monensin in soils and bioadsorbents from Galicia (NW Spain), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17992, https://doi.org/10.5194/egusphere-egu24-17992, 2024.

Salinomycin and lasalocid are polyether ionophore antibiotics commonly used in animal production as anticoccodia. These antibiotics are partially metabolised and excreted at least partially in the active form. Therefore, these drugs enter the environment mainly by direct deposition of urine and faeces on soil, or when manure is applied to soils as fertilizer, facilitating their subsequent entry into the food chain, as well as the development of bacterial resistance and risks to human and animal health. Soils can potentially reduce environmental risks related to these antibiotics through the adsorption on their components, which implies its immobilization. Adsorption depends on the antibiotic characteristics and physicochemical soil´s properties. Some soils have a low capacity to retain antibiotics, for this reason is necessary to investigate low-cost strategies to increase the adsorption capacity of the soils, minimizing environmental pollution. Pine bark, oak ash, mussel shell and olive residue could be used as bioadsorbents of these contaminants, since they have a high adsorption capacity for other antibiotics and are produced in large quantities in several countries. The objective of this work was to investigate the adsorption/desorption capacity of salinomycin and lasalocid of three soils from Galicia (NW Spain) with different properties, and also that of the four residues previously indicated, which could be added to soils to improve the adsorption capacity of these antibiotics. To carried out this work, batch experiments were performed, adding different concentrations (5; 10; 20; 50; 100; 200; 400; 800 and 1000 µmol L^-1) of these antibiotics at 2 grams of soil or 0.5 grams of bioadsorbent samples; the antibiotic concentration in equilibrium solution was measured by HPLC-UV

The results obtained showed that lasalocid was adsorbed completely by the soils in all cases, whereas salinomycin was adsorbed totally by soils when the concentration added was between 5-200 µmol L^-1, however when the concentration added increased (1000 µmol L^-1), adsorption decreased up to 68%.  The results showed that soil with a high pH value (pH=7.97), presented slightly lower adsorption values. In the case of the bioadsorbents, pine bark (pH=3.99), olive residue (pH=5.95) and ash (pH= 11.31) adsorbed 100% of salinomycin in all added concentrations, therefore, these residues could increase the capacity of the soil to adsorb this antibiotic. However, in the case of lasalocid the adsorption by ash was 75%, by olive residue was 94% and 95% by pine bark, when the maximum concentration of antibiotic was added. Mussel shell (pH= 9.39) was the bioadsorbent that presented the lowest adsorption for both antibiotics, 87% for salinomycin and 22% for lasalocid, when 1000 µmol L^-1 was added. Desorption results of salinomycin showed that this is always less than 10% for soils and less than 5% for bioadsorbents. In the case of lasalocid, desorption was less than 3% for soils and bioadsobents.

In conclusion, soils adsorbed 100% of lasalocid, however, salinomycin adsorption was lower. To retain this antibiotic, the use of bioadsorbent would be interesting, specially, pine bark, olive residue and ash, which adsorbed all the added salinomycin.

How to cite: Cela Dablanca, R., Barreiro, A., Míguez González, A., Núñez Delgado, A., Fernández Sanjurjo, M. J., and Álvarez Rodríguez, E.: Salinomycin and lasalocid adsorption/desorption by different soils and bioadsorbents from Galicia (NW Spain)., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18570, https://doi.org/10.5194/egusphere-egu24-18570, 2024.

 Structural iron (Fe³⁺)-bearing clay minerals, when they are reduced, can mediate electron transfer through the Fe³⁺/Fe²⁺ coupling reaction and transform hexavalent chromium (Cr⁶⁺) into less toxic Cr³⁺, which in turn can be removed from the solution by the clay minerals. Two types of clay minerals with different structural iron (Fe³⁺) contents, montmorillonite (2.3 wt%) and nontronite (22.3 wt%), were subjected to reaction with 50 mM dithionite at pH 9 for 48 hours, resulting in Fe²⁺ bearing clay minerals, with measured Fe²⁺ ratios of 0.68 and 0.49, respectively. Subsequently, the Fe²⁺ bearing clay minerals were reacted with Cr⁶⁺ solution with varying pH ranging from 2.5 to 11 in an anaerobic chamber. Results show that the reduction of Cr⁶⁺ was observed at all pH conditions, consistent with the stoichiometric ratios with structural iron (Cr⁶⁺:Fe²⁺/1:3). At pH 7 and below, over 99% of the structural iron (Fe²⁺) participated in the reduction reaction. At pH 9 and 11, however, the reaction exhibited a shortfall, with approximately 7-27% and 20-32% of unutilized structural iron remaining in montmorillonite and nontronite, respectively. According to the Visual MINTEQ model and DTPA extraction experiments conducted on solids obtained, Cr³⁺ is immobilized through sorption onto the clay mineral surface at pH 4.5 and below, and through precipitation and deposition on the clay mineral at pH 7 and above. SEM-EDS analysis, the presence of precipitated Cr at pH 7 and above was identified, and XPS analysis confirmed its precipitation in the form of Cr(OH)₃. 

How to cite: Moon, C., Moon, H., and Nam, K.: Immobilization mechanisms of Hexavalent Chromium When Reduced by Fe2+-Bearing Clay Minerals Depending on solution pH, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7200, https://doi.org/10.5194/egusphere-egu24-7200, 2024.

Increasing global population demands an increased intensity of use of agricultural land, but also to an extension of the use of land previously not suited for agriculture. Likewise, the stabilisation of degraded or reclaimed land e.g. from mining often requires intervention to create conditions which allow soil stabilisation by vegetation.

Mine rehabilitation is often challenged by hard setting or clay rich substrates as the available substrate for shaping the final landform and amelioration is necessary. While chemical amelioration has time limited benefits, long-term physical/mechanical property improvements may lead to better outcomes above all in water limited environments.

In this study we investigated the amelioration of clay substrate with coal with the objective to improve the physical, and potentially also chemical conditions for plant growth. Clay substrate was amended with up to 20%-wt lignite-type coal. The addition of coal occurred in two ways, as fine coal and as crushed coal, still containing aggregates. The clay and clay/coal mixtures were filled into boxes at a height of approximately 0.15m and a total volume of approx. 60 liters. Hydraulic properties were measured following consolidation of the substrate in multiple wetting-drying cycles until the substrate reached a constant height. Samples were extracted to characterise the substrates for their hydraulic and mechanical properties and their biotic activity potential. The test is based on quantifying the production of CO2 through the microbial oxidation of organic carbon compounds in the soil.

The water retention curve tests and analysis (using HYPROP) showed in general an increase of the total pore volume with increase in coal content. The amount of plant available water increased with increase in coal content and was higher with the addition of fine coal, compared to the aggregated coal. The shear strength and cohesive strength decreased with addition of coal. The microbial activity tests showed only small increases in CO₂ production and respiration, along with a low mineralisation rate of the added coal based carbon source. The results show, that the addition of a stable carbon source can be beneficial for the improvement of substrate properties.

How to cite: Baumgartl, T., Baghbani, N., and Bucka, F.: The use of coal as ameliorant for soils with constraints for plant growth, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21834, https://doi.org/10.5194/egusphere-egu24-21834, 2024.

The environmental hazards associated with nuclear power plants, specifically the release of fission byproducts such as strontium (Sr) and cesium (Cs) are highlighted for their harmful attributes, even in non-radioactive forms owing to their physicochemical characteristics and potential health risks. Sr and Cs exhibit significant physicochemical resemblances to calcium (Ca) and potassium (K), respectively. These similarities are so pronounced that the human body often confuses Sr and Cs with Ca and K, leading to their accumulation. This accumulation can give rise to detrimental health conditions, including leukemia, thyroid cancer, bone marrow cancer, and general paralysis. In this study, a soil washing method was employed to eliminate Sr and Cs contaminants from the soil. We hypothesize that the efficiency of Sr and Cs removal is influenced by the resemblance in physicochemical properties. Physicochemical properties such as atomic radius, hydrated radius, electronegativity, and electron affinity of Sr, Cs, Na, Mg, K, Ca, Ba, and Al were carefully studied and summarized for the investigation. Subsequently, solutions with Na, Mg, K, Ca, Ba, and Al at concentrations of 0.1 and 0.01 M, with a pH of 7, were tested for their efficacy in removing Sr and Cs from the soil. The results showed that the greater similarity in hydrated radius between heavy metals and ions appears to be responsible for increased removal efficiencies. For example, both Ca and Sr share the same hydrated radius of 0.412 nm. Interestingly, Ca exhibited the highest efficiency in removing Sr compared to Na, K, Mg, Ba, and Al. Additionally, Ba, with a hydrated radius of 0.404 (the second closest to Sr), demonstrated the second-highest efficiency in Sr removal. Examining results for other heavy metals (i.e., Cd, Co, Cu, Ni, Pb, and Zn), a heightened resemblance in hydrated radii between the heavy metal and ion corresponded to increased removal efficiency, indicating a strong positive correlation. Overall, this study contributes valuable insights into effective strategies for mitigating the environmental impact of nuclear power plant activities on soil contamination.

How to cite: Song, H., Shim, G., and Nam, K.: Removal of strontium and cesium from soil using ion-based washing agents with similar hydrated radii, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13763, https://doi.org/10.5194/egusphere-egu24-13763, 2024.

There are many theories and concepts concerning ecosystem development in natural and semi-natural habitat conditions. The study of spontaneous processes on human-disturbed habitats such as post-excavation mineral habitats provided data revealing that the impact of the specific abiotic factors on any aspect of biotic elements of the developing ecosystems does not follow most of the mechanisms known from the natural and semi-natural habitat conditions. The feedback relations become more complex when the spontaneous vegetation patches and the developing ecosystem start to cover mineral oligotrophic habitats, particular in respect to the biomass soil organic matter and soil substratum parameters. The fundamental process of the biomass and further soil organic matter in mineral soil substratum is based on the non-analogous species composition of the developing vegetation assemblages.

The de novo formed unusual mineral habitats are colonized by not-known plant species vegetation communities. The relationships between the plant species, particularly the dominant plant species, and the abiotic substrate parameters are frequently different than expected. The differences in ecosystem functioning observed in the disturbed habitats led the researcher to use a separate term novel ecosystem.

The crucial observed process is the colonization of the best-adapted plant species individuals. The individuals of the commonly represented species are adapted to extreme drought, salinity,  texture, and pH. The same is true regarding the microorganisms of the colonizing plant's root system. These natural processes provide an opportunity to investigate the relationships between the plant species, particularly the dominant plant species, and the associated organisms and the abiotic substrate parameters. Differences in the chemical and physical properties of the disturbed post-mineral excavation substrates have resulted in unknown, non-analogous species compositions of the vegetation and animal organisms. These differences are reflected in the soil substratum enzymatic activity, the bacteria functional diversity, and soil substratum respiration rates.

The vegetation, biomass, the matter flow beginning, growing on the mineral material of the post-coal mine heaps consists of a mosaic of patches dominated by various species assembled in a variety of microhabitats. This mosaic reflects the diversity of abiotic habitat conditions. The taxonomic species diversity is followed by the functional vegetation diversity and the variety of plant individual's responses to environmental stressors.

Post-mineral excavation sites deliver an example of newly established habitats that differ from the natural ecosystems current in the surrounding landscape. These findings brought us to present a comprehensive concept for the management of post-industrial sites based on natural processes, that is necessary to be applied to recover the ecosystems after disturbance. This concept enables the application of the natural processes, in a site-specific approach in the disturbed or de novo established sites. The return to previous ecosystems should not be considered. The enhancement of the novel ecosystem development in urban and industrialized landscapes is the prerequisite of the modern economy.

How to cite: Wozniak, G., Kompała-Bąba, A., Hutniczak, A., Bierza, W., and Błońska, A.: The comprehensive concept for the management of post-industrial sites based on natural processes, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6709, https://doi.org/10.5194/egusphere-egu24-6709, 2024.

Petroleum-contaminated soils are difficult to remediate due to a wide range of point/nonpoint sources of pollution and complex components. Here, a new leaching agent system was developed and synthesized, including oligomers, to construct the leaching process and optimize the soil leaching process parameters. The new agent has improved skeleton structure, green bio-based surfactant molecules, and synergists. Based on the characteristics of the leaching soil and its flora structure, more than 60 strains of petroleum degradation bacteria were isolated and screened. Furthermore, suitable bacteria for degradation were cultivated, the nutritional formula and process flow were optimized, and the microbial agent formula for heavy oil, polycyclic aromatic hydrocarbons and other pollutants were established. According to the physical characteristics of different types of oily sludge and soil, an economical and efficient remediation technology system and supporting implementation process were established, and finally, a "leaching-bioremediation" coupling treatment process was formed. The PHs content of the actual contaminated soil after the treatment was lower than 0.45%, and 12,000 t of PHs contaminated soil was remediated. Through the study of the elution-bioremediation process, the establishment of economical and environmentally friendly remediation technology and the process will improve our knowledge to solve the sudden oil pollution in contaminated areas and the environmental protection solution of historical problems.

How to cite: Qin, B. and Ren, L.: Coupling Leaching-Bioremediation for Petroleum-Contaminated Soils, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-594, https://doi.org/10.5194/egusphere-egu24-594, 2024.

To investigate this strategy, 15 field scale trials were implemented in five countries [1].  These have evaluated the performance of Phalaris, Miscanthus, 2 x Saccharum and 2 x Pennisetum species for combined energy crop production, phyto-remediation and or phyto-management of contaminated land in Brazil and Europe.  Reed canarygrass (Phalaris arundinacea) is a native perennial rhizomatous C3 species suitable for non-agricultural or marginal lands and climatic zones such as Scotland (where C4 Miscanthus x giganteous cannot be grown effectively).  Our phytoremediation trials using Phalaris in Italy and Ukraine are the first we are aware of.

Given the wide variety of non-agricultural marginal lands [2], species selection must combine significant biomass production on marginal land with acceptable levels of biomass contamination for subsequent use or energy conversion.  Whereas specialist hyperaccumulator plants may achieve higher absolute concentrations of contaminants and exhibit greater bioconcentration and translocation factors, their inherently lower biomass productivity means that both biomass, energy yield and total mass of contaminants removed per unit area will be relatively small.  In contrast, high yielding, low contaminant uptake characteristics, such as for conventional energy crop species, would result in greater energy production, economic viability and greater potential for biomass utilisation.

In the UK the CERESiS project has utilised long-term field trials originally established during the BioReGen (Biomass, Remediation, re-Generation: Reusing Brownfield Sites for renewable energy crops) EU Life demonstration Project (LIFE05 ENV/UK/000128) in 2007.  These allowed direct comparison of the actual contaminant removal rates of three crop species:  Although the biomass of Miscanthus and short-rotation coppice Salix contained higher concentrations of certain elements, Phalaris far out-performed these in terms of biomass, ease and economy of production [3].  Surprisingly, despite lower contaminant concentrations in Phalaris, such was the increased biomass yield that the total mass removed was still greater than for Miscanthus or Salix.  Likewise Pennisetum (Napier and Capiaçu grasses) shows similar promise in Brazil as the most productive, resulting in the highest offtake of Cr from soils contaminated with this element.  This suggests that low-uptake phyto-excluding plants which can tolerate contaminated soils and grow productively might still represent the best and most economically viable option for clean-up of contaminated sites. Meanwhile this nature-based solution can simultaneously deliver a variety of wider societal and environmental benefits, such as greening-up derelict land or the enhanced storage of carbon in soil [4].

This paper will investigate this strategy by comparing biomass yield, biomass contamination and the calculated offtake of contaminants for a wide range of generic contaminants across all of the CERESiS trial sites.  This will be used to evaluate the potential trade-offs between biomass suitability for use and phyto-management of contaminated land.

 [1] This study is part of the CERESiS (ContaminatEd land Remediation through Energy crops for Soil improvement to liquid biofuels Strategies) Project which has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 101006717, www.ceresis.eu

 [2] Mellor et al 2020, RaSER 135, 110220

 [3] Lord, 2015, BioBE 78, 110-125

 [4] Lord & Sakrabani, 2019, STotEn 686, 1057-68

How to cite: Nunn, B., Torrance, K., Wright, B., Colantoni, A., Bianchini, L., Alemanno, R., Tryboi, O., Severino, M., Leandro, W., and Lord, R.: Growing perennial rhizomatous grasses on contaminated land: a strategy for combining phyto-management with sustainable biomass production?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7435, https://doi.org/10.5194/egusphere-egu24-7435, 2024.

Salinity is one of the challenges affecting seed germination and establishment in dryland restoration projects. Seeds must overcome the osmotic pressure present in saline soils before they can germinate. An ideal method is to reduce the osmotic potential through continuous irrigation to flush out the excess salts from the soil to enable seeds to germinate. However, such a system is impractical at scale and would exponentially increase restoration budgets. Research has shown that bacteria and cyanobacteria individually improve seedling germination. However, it is unclear whether bacteria and cyanobacteria improve seedling germination individually and as combined entities under dryland conditions. In this glasshouse study, we test the hypothesis that, inoculating seeds with bacteria, cyanobacteria and the combination of both will increase seed germination outcome compared to their none inoculated counterpart. We also examined which microbial inoculation would yield the greatest seedling germination and biomass. We found that all inoculated seeds with microorganisms significantly increased seedling emergence and biomass production compared to the non-inoculated seeds. The highest seedling emergence was found in the cyanobacteria treatment followed by the combined bacteria and cyanobacteria treatment. Similarly, the highest biomass production occurred when seeds were inoculated with cyanobacteria treatment followed by bacteria treatment. Our results suggest that, cyanobacteria can be used as a potential tool to overcome seedling germination challenges in saline dryland ecosystems during restoration.

How to cite: Dadzie, F., Machado, N., and Muñoz-Rojas, M.: Indigenous soil microbial inoculants promote restoration of arid plants in saline soils, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12662, https://doi.org/10.5194/egusphere-egu24-12662, 2024.

Soil microorganisms control important ecosystem functions such as nutrient cycling, plant productivity and climate regulation. Thus, microbially assisted conservation and restoration has the potential to reconnect above and belowground dynamics, creating functional ecosystems that are more resilient to climate change impacts. In this research, we (i) assessed the responses of soil microbial communities to disturbance, e.g., severe fire, and extractive activities such as mining, and (ii) developed bioinoculants composed of locally sourced soil bacteria from the rhizosphere and biocrust cyanobacteria, to promote plant growth and soil fertility and enhance ecosystem capacity for global change adaptation. This presentation will showcase some key findings of these studies conducted in contrasting Australian ecosystems (shrubland-grassland in the arid zone, and subtropical/temperate forests). These outcomes include the successful translocation of whole-soil communities for inhibiting weeds, and the effective use of indigenous microbes (rhizobacteria and cyanobacteria combinations) for soil carbon sequestration, nitrogen fixation, and growth promotion of key arid and temperate plant species.

Overall, our research demonstrates the benefits of using native microbial communities as bioinoculants in ecosystem restoration. The emerging technologies used in our research, i.e. seed enhancement through seed biopriming and biopellets, have a large potential for landscape-scale conservation and restoration programs in the context of global change.

How to cite: Muñoz-Rojas, M., Dadzie, F., and Machado de Lima, N.:  Soil microbial based strategies and seed enhancement technologies reconnect plant-soil biodiversity and improve restoration outcomes , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16797, https://doi.org/10.5194/egusphere-egu24-16797, 2024.

Fire is a natural element of the landscape; however, it can also have serious effects on the environment. Although the effect of fire on plant communities has been broadly studied, we lack information on the effect of fire on soils. Several types of post-fire treatments have been applied in Mediterranean areas for soil protection and potential regeneration of soil fertility, i.e. logging or mulching. Yet, the effect of these treatments on the soil biodiversity are not fully understood.

Here, using different soil physical and biological approaches methods, we analysed the impacts of different post-fire treatments on the composition and diversity of microbial communities (bacteria and fungi) in a Mediterranean forest. Our results showed substantial differences in the responses of the fungal community to the different post-fire treatments, i.e. straw mulching and salvage logging . Opposite, the soil bacterial community was not affected by the post-fire treatments. Overall, soil fungi were more sensitive than bacteria to fire, but the recovery of this taxa following the fire event was faster. Our results can provide useful information for restoration of fire-impacted areas in the Mediterranean region.

How to cite: Roncero Ramos, B., Romero, M., Plaza Álvarez, P. A. P. Á., Lucas-Borja, M. E., and Muñoz-Rojas, M.: Post-fire restoration impacts on soil microbial communities in a Mediterranean region, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12514, https://doi.org/10.5194/egusphere-egu24-12514, 2024.

Phytoremediation is considered as an environmentally friendly and cost-effective technology for the treatment of contaminated soil. Recently, there has been an increase in large-scale phytoremediation projects, one of the key moments of which is the transition from a pot experiment to large-scale field research under real conditions. The “Phy2Climate” project aims to provide clean biofuel production and phytoremediation solutions from contaminated lands worldwide, and field trials under real conditions was a focal point in this project. The trials were established in countries like Serbia, Spain, Argentina, and Lithuania, to cover different climatic conditions and differently polluted areas.

In Lithuania, the field trials were established in a site that was formerly used as oil base in Soviet times and up-until-today exhibits contamination with petroleum hydrocarbons. Main method for phytoremediation of petroleum-contaminated soil is the rhizodegradation, which focuses on stimulating the population of organic-degrading microorganisms through the plant rhizosphere. Thus, contaminated soil in the site was amended with organic and mineral fertilizers to promote plant development and increase biomass outputs. Furthermore, microbial  additive applied to ensure rhizodegradation. Two monocultures (amaranth (Amaranthus caudatus) and Jerusalem artichoke (Helianthus tuberosus) and a mix of herbaceous plant species were grown on different subplots in the prepared soil for two consecutive years. The key parameters used to assess the efficiency of phytoremediation included biomass output, crucial for ensuring an adequate amount for biofuel production, and the phytoremediation factor, indicating changes in petroleum hydrocarbon concentration in the soil.

How to cite: Kidikas, Z., Rubezius, M., and Kasiuliene, A.: Experience of a two-year phytoremediation field trial in the “Phy2Climate” project: Lithuanian case, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20237, https://doi.org/10.5194/egusphere-egu24-20237, 2024.