Orals: Tue, 29 Apr | Room 0.51
One of the major global challenges of agriculture is to meet the increasing food demand while combating soil degradation, which affects over 40% of arable lands. This degradation escalates reliance on mineral fertilizers and heightens the risk of environmental deterioration. The valorization of agricultural, livestock, and forestry wastes through their conversion into organic amendments emerges as a pivotal strategy to restore soil health, enhance agricultural productivity, and manage waste efficiently. This aligns with the EU Soil Mission’s goal to ensure that at least 75% of soils are healthy and functional under the “A Pact for Soil in Europe” initiative.
This contribution will show how applying organic residues from agriculture and livestock, processed into green compost, digestate, or biochar, can serve as effective organic amendments. The use of olive mill waste biochar in deficit-irrigated olive crops led to increased plant photosynthesis rates, water use efficiency, and Carbon sequestration, significantly boosting stable soil carbon content. Additionally, the presentation will highlight the effects of applying green compost, and biochar, both individually and in combination with liquid amendments (compost tea, cow manure digestate and cow slurry), on acidic and alkaline soils. The results indicated that biochar significantly enhanced carbon stability (up to 9 times). A high dose of compost tea negatively impacted plant germination and growth, whereas a mix of compost and biochar improved water retention and productivity in both soil types. These findings underline the importance of selecting appropriate organic amendments to optimize soil health and agricultural performance. They also emphasize the crucial role of waste valorization from agricultural and livestock sectors in promoting sustainable farming practices, improving soil resilience, and contributing to carbon sequestration, crucial in advancing towards a sustainable agriculture.
Acknowledgments: Funding for the AGRORES and RES2SOIL projects (PID2021-126349OB-C21 and PID2021-126349OB-C22) by MCIN/AEI/ 10.13039/501100011033 is gratefully acknowledged. Additional support from the Junta de Andalucía, the EU (EAFRD), and the AEI association through Resioliva Operational Group (File No. GOPO-CO-23-0004) is also appreciated.
How to cite: De la Rosa, J. M., Domínguez, S., Perez-Dalí, S., Sánchez-Martín, Á., Márquez-Moreno, J., Gutierrez-Patricio, S., Moreno, A., Cubero, B., Martín-Sánchez, P. M., Souza, P., Merino, A., Rodríguez-López, C., Knicker, H., Campos, P., González-Pérez, J. A., and Bárcenas, G.: From waste to worth: Harnessing residual biomass to boost soil quality and carbon sequestration, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3290, https://doi.org/10.5194/egusphere-egu25-3290, 2025.
Population growth, combined with expanded sanitation coverage, has resulted in a significant global increase in organic waste generation from municipal and agricultural sources. Simultaneously, the rising nutrient demands of agriculture to support a growing population and the widespread degradation of soils underscore the urgent need to integrate sustainable waste management and nutrient recovery into agricultural systems. These efforts are essential to restore soil health and ensure long-term productivity.
The growing market demand for sustainable products—driven by societal expectations and, in part, by Environmental, Social, and Governance (ESG) frameworks in corporate reporting—presents a unique opportunity to capitalize on the sustainability benefits of waste-derived fertilizers. To streamline ESG reporting for both waste management and agricultural systems, we propose a structured framework that could serve as a standard for waste-derived fertilizers. This framework categorizes these products based on sustainability attributes, safety (e.g., contaminant and pathogen risks), and efficacy (e.g., performance in soils), while enhancing organizational efficiency and scalability to facilitate broader adoption in agriculture.
Drawing on insights from industry stakeholders across the value chain, this novel four-generation framework outlines the transformation or extraction of organic biowaste—including food waste, biosolids, and manures—into sustainable soil amendments (e.g., compost, digestate), high-value waste-derived fertilizers (e.g., struvite, urea), and innovative multifunctional fertilizer products. Generation 1 includes raw, untreated wastes like food scraps and manure, which require stringent regulatory oversight. Generation 2 features processed organic waste streams, such as compost and digestates, which primarily function as soil amendments with high application rates. Generation 3 focuses on bioengineered fertilizers, including organomineral and hybrid products, which achieve nutrient concentrations comparable to conventional fertilizers while maintaining sustainability through recovery from waste streams. Generation 4 highlights multifunctional products capable of reducing greenhouse gas emissions (scope 1, 2, or 3), sequestering carbon, and aligning with carbon farming frameworks, all while remaining effective as fertilizers.
This framework systematically categorizes waste-derived products, provides detailed examples and chemical compositions, supports ESG compliance with clear sustainability metrics, and promotes scalability, pollution mitigation, and enhanced soil health. It offers a transformative tool for embedding circular economy principles into waste management and agricultural production, addressing critical environmental and economic challenges on a global scale.
How to cite: Mickan, B., Mercer, G., Jenkins, S., Pool, K., and Ryan, M.: Proposing a Generational Framework for Waste-Derived Fertilizers: A New Approach to integrating Sustainable Agriculture and Waste Management, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1402, https://doi.org/10.5194/egusphere-egu25-1402, 2025.
Silicon (Si)-rich biomass feedstocks are generated annually from agricultural crop production. In this study, we explored the potential of converting Si-rich biomass to biochar as a soil amendment of both nutrient supply and disease resistance for crop production. Silicon-rich rice straw/husk, sugarcane harvest residue, and miscanthus were collected and converted to biochar. Pretreatment of biomass with KOH and other alkali reagents was carried out to increase Si bioavailability and enrich nutrients of biochar. Converted biochar products were characterized for their Si-releasing behavior and plant uptake. Results showed that depending on total Si contents of feedstocks utilized, varying amounts of plant-available Si were released. Alkali pretreatment caused the bleaching of phytolith-Si to increase Si release from biochar. Alkali-enhanced biochars from rice straw or husk yielded the higher extractable Si as pyrolysis temperature increased from 350oC to 550oC. More soluble Si was also released in unbuffered weak acid and neutral salt solutions for alkali-enhanced biochars produced. Potting studies with perennial ryegrass showed that alkali-enhanced biochars increased tissue Si content and suppressed gray leaf spot development. Rice greenhouse trials also illustrated that the application of alkali-enhanced biochars, especially those made from rice husk at 550oC, increased Si uptake and rice grain yields compared to lower temperature and non-enhanced biochars. Overall, alkali-enhanced-biochar could be used as a multifunctional soil amendment for improving plant growth.
How to cite: Wang, J., Wang, M., Zhou, B., and Jeong, C.: Converting Si-rich biomass into a multifunctional soil amendment and its effect on plant growth , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2612, https://doi.org/10.5194/egusphere-egu25-2612, 2025.
The synergistic effects of engineered biochar (EB) and organic fertilizers on plant growth, yield, and fruit quality of bell pepper (Capsicum annuum) and tomato (Solanum lycopersicum) were assessed through a field study in tropical laterite soil in West Bengal, India. EBs were synthesized via slow co-pyrolysis of Eucalyptus biomass with waste plastics (polystyrene and low-density polyethylene) under optimized process conditions. The experimental design consisted of 40 treatments, incorporating three EB application rates (5, 10, and 15 t ha⁻¹) with or without fixed quantities (20 t ha⁻¹) of organic fertilizers—manure, vermicompost, and their 1:1 (w/w) mixture—alongside negative and positive controls. Co-application of EB and manure significantly enhanced plant growth and fruit yield, achieving increases of 112% (bell pepper) and 84% (tomato) compared to manure alone. Relative to the control, fruit yield improvements reached 238% for bell pepper and 198% for tomato. Notable enhancements in fruit quality parameters and mineral content were observed under combined EB and organic fertilizer treatments. While EB application rates and organic fertilizer types exhibited significant effects, the type of biochar showed minimal influence on outcomes. Unlike the rapid nutrient release dynamics characteristic of organic fertilizer-soil mixtures, co-application of EB and organic fertilizers facilitated higher nutrient retention and gradual release dynamics. The study identified 10 t ha⁻¹ EB combined with manure as the optimal treatment for maximizing bell pepper and tomato productivity in tropical laterite soils.
How to cite: Vanapalli, K. R., Bhattacharya, J., and Dubey, B.: Synergistic effects of engineered biochar and organic fertilizers on the plant growth, yield, and fruit quality of bell pepper and tomato in a tropical laterite soil, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4609, https://doi.org/10.5194/egusphere-egu25-4609, 2025.
Carbon-rich products from pyrolysis (pyrochars) and hydrothermal carbonization (HTC, hydrochars) have been proposed as soil amendments to mitigate greenhouse gas emissions and increase production. This research compared the amendment impact of two different types of biochars on GHG emissions in tomato production and their major functional characteristics. Fluxes of CO2, CH4, and N2O were measured in the tomato growing pots using a manual static chamber method during the tomato growing season. The temperature and soil moisture were measured continuously using sensor pups, and the results were transferred to a data retriever. The collected gas samples were analyzed using a gas chromatograph (model 8610C, SRI Instruments). Nitrous oxide was detected with the electron capture detector (ECD) operated at 325°C, and CO2 and CH4 were measured with a mechanized interface with a îame ionization detector (FID). These results demonstrate that pyrochar application significantly decreased N2O emission compared to the emission from the control treatment. We observed that two different soil amendments did not substantially improve tomato production. This study also focuses on comparing the occurrence of 16 PAHs regulated by the US EPA in 22 char samples. Results showed that the sum of the 16 EPA PAHs in all samples was well below the requirements in the two standards, except for a pyrochar produced at the farm scale. They ranged from 131 to 9358 µg·kg-1 in the seven pyrochars and from not detected to 333 µg·kg-1 for the fourteen hydrochars. Our findings indicate that hydrochar produced via hydrothermal methods exhibits much lower concentrations and toxicity of the 16 PAHs regulated by the US EPA than pyrochars, making them a potentially safer option for soil amendment and environmental applications.
How to cite: Jeong, C., Ro, K., Wang, J., and Lee, M.: Comparison study of carbon rich products under thermal carbonization and hydrothermal carbonization on their characteristics, greenhouse gas emission, and tomato growth. , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7910, https://doi.org/10.5194/egusphere-egu25-7910, 2025.
Agriculture and food systems account for one-third of the anthropogenic GHG emissions. As the largest terrestrial carbon pool, soils play a significant role in climate change mitigation and adaptation processes. Due to different agricultural inputs and their intensive usage, agricultural soils are more vulnerable to carbon loss and act as a source of GHG emissions while diminishing the soil's inherent capacity to act as a carbon sink. The composition, stoichiometry, and quantity of applied soil amendments differ and significantly influence soil carbon retention in the long run. Combining organic amendments and inorganic fertilizers could affect soil organic matter (SOM) stabilization pathways differently. The latter is identifiable via SOM composition and overall compound diversity. It has been hypothesized that more persistent soil organic matter is characterized by high molecular compound diversity and complexity (Lehmann et al., 2020). The molecular composition of the soils can further be categorized into plant, microbial, and mixed-originated compounds to understand the preferential carbon stabilization pathways under different nutrient management conditions. Besides, the energy released during oxidative differential scanning calorimetry could be used to assess the degree of SOM transformation. Within this context, this study aims to assess the long-term impact of organic amendments under different inorganic N fertilizer levels on soil organic matter content, their molecular composition, and transformation. Here, we analysed soil sampled from a long-term field experiment in Switzerland spanning over 45 years, which contains treatments with varying levels of mineral N fertilization (no mineral N, recommended N application dose ± 40 N units) and organic amendments (no organic amendments, farmyard manure, and wheat straw). The bulk soils and organic amendments were analysed for their elemental composition, molecular composition using pyrolysis gas chromatography-mass spectrometry, and thermal stability using simultaneous thermal analysis. The initial results indicate that soils receiving no organic amendments and no inorganic N fertilizers exhibited significantly lower carbon content, more recalcitrant compounds, and lower molecular compound diversity than other treatments receiving organic amendments. Concurrently, soils receiving no organic amendments and no inorganic N fertilizers exhibited lower energy release during thermal analysis, indicating more transformed SOM. According to the principal component analysis, there was a clear demarcation between manure/straw-added treatments and not-added treatments related to the composition of soil organic matter. The manure-added treatments exhibited significantly higher carbon content, manure-derived sterols, and molecular diversity than the non-manure-added treatments. Furthermore, we expect to showcase the interaction effect of organic amendments and inorganic N fertilizers on the proportion of microbial and plant-derived compounds in soil organic matter. Overall, the findings of this study will provide useful information for stakeholders to identify the optimum fertilization practices for croplands to increase the stable SOM fraction in the long run.
References:
Lehmann, J., Hansel, C. M., Kaiser, C., Kleber, M., Maher, K., Manzoni, S., ... & Kögel-Knabner, I. (2020). Persistence of soil organic carbon caused by functional complexity. Nature Geoscience, 13(8), 529-534.
How to cite: Rathnayake, D., Steiner, S. K., Leifeld, J., and Guillaume, T.: Long term impact of organic amendments on soil organic matter molecular composition , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11652, https://doi.org/10.5194/egusphere-egu25-11652, 2025.
Crop diversification is hypothesized to enhance the diversity of soil organic matter (SOM) and its associated microbial communities. However, the specific impacts of crop diversification on SOM composition and its associated microbial communities remain poorly understood.
This study, conducted as part of the EJP Soil – Energylink project, investigates agricultural soils across Europe located along a pedo-climatic gradient. The studied locations include long-term field experiments in Sweden, the Netherlands, Austria, the Czech Republic, Slovenia, France, and Spain. To assess potential seasonal effects, multiple sampling campaigns were conducted at some sites. Topsoil (0-20 cm) bulk samples from all sites were analyzed for carbon (C), nitrogen (N), and phosphorus (P) contents. SOM diversity was evaluated using solid-state 13C NMR spectroscopy. Microbial communities were characterized via phospholipid fatty acid (PLFA) analysis, quantifying both the ratio fungi/bacteria (F/B) and the ratio Gram-positive / Gram-negative bacteria (G+/G-), and overall microbial biomass.
In general, trends for C, N or P contents in diversified plots compared to controls were no consistent across sites. Preliminary results suggest that crop diversification has a minimal effect on SOM diversity. In most countries, SOM composition showed little or no significant differences between plots with different levels of crop diversification. However, significantly lower humification indices (O-alkyl C / alkyl C) were detected in diversified plots from the Czech Republic and Slovenia in both studied seasons. In Spain and France, significant differences in this parameter were limited to seasonal variations. The most pronounced differences in SOM composition occurred at sites with strong contrasts in soil disturbance between control and treatment plots (e.g. bare soil vs. cover crops). Similar results were obtained for PLFA, indicating a higher microbial biomass with increasing diversity, although these differences were not statistically significant at most sites. Comparably, a higher fungal/bacterial ratio was generally observed in more diversified plots, but without significant variation. G+/G- did not appear to have a consistent trend across sites. In conclusion, crop diversification appears to have limited effects on SOM diversity and associated microbial communities. Further analysis is needed to confirm these preliminary results and to better understand the interactions between crop diversification practices and SOM.
Keywords: solid-state 13C NMR spectroscopy, PLFA, biodiversity, sustainable agriculture
Acknowledgments: This work is financed by the project EJP Soil/Energylink, which received funding through the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 862695
How to cite: Gismero Rodríguez, L., Velasco-Molina, M., König, A., Inselsbacher, E., Herrmann, A., Hanegraaf, M., Schroeder, J., Valverde, A., and Knicker, H.: Effect of crop diversification on soil organic matter: a study along a pedo-climatic gradient in Europe, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1019, https://doi.org/10.5194/egusphere-egu25-1019, 2025.
It is well established that the application of organic amendments (OA) to weathered soils increases the availability of soil or fertilizer phosphorus (P). It is often assumed that organic anions derived from OA compete with P for sorption sites on iron and aluminium oxides. Alternatively, the short-term effect of OA amendment on raising the pH has also been proposed as a mechanism. These potential mechanisms have never been tested in a P diffusion experiment that indicates the P mobility. In this study, a P diffusion experiment was set up with a Vietnamese Ferralsol treated with compost, lime, or a combination of both, in addition to an untreated control. Phosphorus adsorption isotherms were constructed for each treatment. Soils were incubated in Petri dishes with triple superphosphate (TSP) fertilizer granule placed at the center, while an additional compost treatment was incubated without TSP. Phosphorus diffusion was visualized at 1, 5, and 14 weeks using the diffusive gradient in thin films (DGT) technique; the P concentration in the DGT was visualized via colorimetry. Concentric soil sampling was performed after DGT deployment to measure P concentrations at increasing distances from the fertilizer granule. Results confirmed a strong positive effect of OA application on the availability of added P in time and distance. At 5 and 14 weeks, the +OA +TSP treatments increased soil P concentrations compared to -OA +TSP treatments up to twofold near the fertilizer granule (< 0.8 cm) and up to ninefold at distances of 0.8–1.6 cm. In the control and limed treatments, P concentrations showed a consistent downward trend in time. In contrast, they first increased (week 5) and then slightly decreased (week 14) in the OA and Lime+OA treatments, but always remained above the threshold value of 0.2 mg P/L necessary for plant growth. Soil 0.01 M CaCl2 extractable P concentrations in the different treatments increased (Control < Lime < Lime+OA < OA) with decreasing solid-liquid distribution coefficients (KD) recorded in the P adsorption isotherms, indicating that reduced P sorption was the mechanism for increased P availability. The OA treatment incubated without TSP showed no detectable P at any time point, confirming that the OA itself was not a direct P source. Additionally, the increased P availability in compost-amended soils was not attributable to changes in soil pH, as all treatments raised the pH by 1.5 ± 0.5 units. We conclude that OAs enhance P availability in weathered soils primarily by modifying P sorption rather than directly supplying P or altering soil pH. This mechanism underscores the potential of OAs to improve fertilizer P use efficiency and sustain crop production in nutrient-poor soils.
How to cite: Van Ryckel, H., van Dael, T., and Smolders, E.: Organic matter increases availability of phosphate in tropical soils: a phosphate diffusion experiment, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11310, https://doi.org/10.5194/egusphere-egu25-11310, 2025.
Methane emissions from landfills are a significant contributor to global warming. Harnessing methane-oxidizing microorganisms in the topsoil layer represents a highly efficient strategy to reduce uncontrolled methane release from landfills. Biochar is a material rich in carbon, derived from the thermal decomposition of organic waste. It boasts a range of superior physical and chemical attributes, which render it a potent amendment for boosting the methane-consuming capabilities of landfill cover soils. Digestate biochar is produced by the pyrolysis of digestate from anaerobic digestion. A large amount of digestate is produced during the anaerobic digestion process. Pyrolysis treatment can rapidly reduce the volume of digestate while yielding high nutrent (K, Na, Fe, Ca) biochar products. These nutrients that typically promote the growth and metabolism of microorganisms and plants. Applying digestate biochar to modify landfill cover may be a “treat waste with waste” approach, but the effects of biochar application in landfill cover soil still need further investigation.
Control groups without biochar and with woody biochar were established to contrast with digestate biochar, in order to investigate the impact of digestate biochar on the growth and metabolism of methanotrophs communities under conditions of 15% methane and 15% oxygen. Long-term semi-open ecological experiments were also set up to investigate the dynamic trends of elements in different biochar-amended soils, focusing on their downward migration with precipitation and upward migration through plant uptake.The digestate biochar exhibited superior performance in enhancing methane oxidation over woody biochar. The incorporation of both woody biochar and digestate biochar facilitated methane oxidation, with digestate biochar showing almost double the cumulative mass of methane oxidation (7.14 mg methane per gram) relative to woody biochar. It was determined that superior ion-exchange capacity of digestate biochar better supported the proliferation of Type I methanotrophs, which possess more effective metabolic routes for methane oxidation. In subsequent experiments, the highest daily methane oxidation rate in digestate biochar-amended soil was about 7 times that of the original soil and woody biochar after 6 months of plant growth. Moreover, the digestate biochar-amended soil consistently had the largest cation exchange capacity. The soil amended with digestate biochar had lower dissolved organic carbon (DOC) compared to the control group without biochar addition, while the recalcitrant organic carbon was higher than the control group. In contrast, the DOC and recalcitrant organic carbon in the woody biochar amended soils were significantly higher than those in the control group.
In general, applying digestate biochar to landfill cover soil for methane reduction is highly significant in terms of "treat waste with waste" engineering. Our research confirmed that digestate biochar does not possess heavy metal leaching toxicity; instead, it provides nutrients for the growth and metabolism of plants and microorganisms in the soil. Our results may offer crucial insights for devising and refining soil restoration approaches using biochar to reduce greenhouse gas emissions.
Keywords: Digestate biochar; Methane oxidation; Landfill cover soil; Cation exchange capacity; Organic carbon.
How to cite: Bai, X., Zhao, N., Huang, K., and Xu, Q.: Effect of Digestate Biochar Application on Methane Oxidation in Landfill Cover Soil, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7048, https://doi.org/10.5194/egusphere-egu25-7048, 2025.
Abstract
The characterisation of biochars produced from diverse feedstocks, including dry manure, digestate manure, biologically treated dry sewage sludge, and chemically treated digestate sewage sludge, was conducted using Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). These analyses revealed significant structural and chemical transformations during pyrolysis at 400°C and 600°C, influencing the biochars' suitability for applications in soil improvement, nutrient retention, and carbon sequestration.
FTIR analysis indicated distinct functional group changes in all biochars, particularly reductions in hydroxyl (-OH) and carbonyl (C=O) groups, reflecting dehydration and the breakdown of oxygenated compounds. Aliphatic C-H peaks diminished, signifying increased aromaticity and the formation of more stable carbon structures. Nitrogen-related functional groups decreased across all feedstocks, suggesting nitrogen stabilisation into recalcitrant forms. Persistent phosphate (P-O) and metal oxide peaks confirmed the retention of essential nutrients such as phosphorus, calcium, and magnesium, making biochars valuable for soil fertility enhancement.
XRD analysis provided further insights into the mineralogical transformations in biochars. Dry manure biochars showed the formation of stable crystalline phases such as berlinite (AlPO₄) and sylvite (KCl), which contribute to phosphorus and potassium retention, respectively. Digestate manure biochars exhibited additional silicate and aluminosilicate phases, enhancing their cation exchange capacity (CEC) and nutrient-holding potential.
Biologically treated dry sewage sludge biochars demonstrated significant phosphorus stabilisation in berlinite and chlorapatite and retaining silicates like quartz and mica. These mineralogical changes enhance biochar's potential as a slow-release fertiliser while improving soil structure and aeration. Similarly, biologically treated digestate sewage sludge biochar retained essential nutrients like sulfur and silicon, with increased crystallinity ensuring better structural stability and moisture retention. The presence of barite (BaSO₄) and gypsum (CaSO₄·2H₂O) highlighted the biochar's ability to retain sulfur, an essential nutrient for plant growth and metabolic processes.
Chemically treated sewage sludge biochars exhibited stronger silicate and phosphate peaks, reflecting enhanced inorganic content and long-term stability. Variscite (AlPO₄·2H₂O) transformed into berlinite during pyrolysis, stabilising phosphorus for sustained nutrient availability. Sylvite (KCl) emerged as a significant phase, providing a readily available potassium source vital for crop yield and stress tolerance. The presence of calcite and gypsum further supported the biochar’s liming capacity, which is helpful for pH regulation in acidic soils.
The findings underline the importance of feedstock selection and pyrolysis conditions in tailoring biochar properties for specific environmental and agricultural applications. Pyrolysis stabilises organic matter and enhances biochar’s structural integrity, nutrient retention, and pollutant adsorption capacity. This study highlights the potential of biochar to address soil degradation, improve crop productivity, and support sustainable waste management in agriculture.
How to cite: Bezabeh, M. W., Krogstad, T., and Eich-Greatorex, S.: Characterisation of biochar from manure and sewage sludge using XRD and FTIR, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20231, https://doi.org/10.5194/egusphere-egu25-20231, 2025.
Posters on site: Tue, 29 Apr, 14:00–15:45 | Hall X4
Sustainable food waste (FW) management is increasingly vital for addressing environmental challenges and advancing the circular economy. Conventional practices, such as landfills and incineration, lead to resource loss and environmental challenges. Anaerobic fermentation (AF) offers an environmentally friendly and efficient alternative, enabling the transformation of food waste into valuable byproducts like volatile fatty acids (VFAs). This study aimed to investigate the thermal pretreatment effects and Saccharomyces cerevisiae inoculation on AF of FW, using cabbage (a carbohydrate-rich feedstock) and chicken breast (a protein-rich feedstock) as representative feedstocks of FW.
The results revealed that thermal pretreatment significantly enhanced the solubilization of polysaccharides in cabbage, resulting in the rapid production of soluble saccharides and VFAs within two days. Moreover, thermal-treated carbohydrates improved S. cerevisiae fermentation efficiency, highlighting the suitability of carbohydrate-rich feedstocks for AF applications. In contrast, thermal pretreatment of chicken breast facilitated protein denaturation but did not substantially increase VFA yields after 24 days, suggesting a limited potential for protein-rich substrates in AF efficiency. Comparatively, carbohydrate-rich feedstocks showed more favorable for optimized fermentation performance than protein-rich feedstocks.
Microbial community analysis showed that thermal pretreatment influenced microbial dynamics during the AF process. Cabbage feedstocks exhibited an increased abundance of carbohydrate-degrading bacteria, facilitating the efficient conversion of polysaccharides into VFAs. Conversely, protein-degrading bacteria dominated meat-based feedstocks, yet the fermentation efficiency remained constrained, reflecting the intrinsic differences in feedstock composition. These observations underlined the importance of feedstock selection and pretreatment strategies in achieving effective resource valorization.
This research highlighted the role of thermal pretreatment in improving the AF of carbohydrate-rich substrates, providing a pathway for enhanced VFA production and resource recovery. The study also emphasized the need for further optimization of AF for protein-rich feedstocks, potentially through alternative pretreatment methods or microbial consortia adjustments. By advancing the understanding of the interplay between feedstock characteristics, thermal pretreatment, and microbial dynamics, this work contributed to developing sustainable waste management technologies and supported the broader goals of the circular economy.
How to cite: Fan, C., Lee, Y.-Y., and Huang, C.-H.: Effect of food waste thermal pretreatment on VFA production and microbial dynamics by anaerobic fermentation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2084, https://doi.org/10.5194/egusphere-egu25-2084, 2025.
Agricultural waste is produced in significant quantities worldwide, with 258 million tons of crop residues generated annually in the European Union alone. Improper management of these residues can result in environmental issues, including soil and water contamination and greenhouse gas emissions, exacerbating climate change. Pyrolysis of residual biomass offers a sustainable solution by converting agricultural waste into valuable products: syngas (a methane-rich gas), biochar (a porous carbonaceous solid), bio-oil, and pyroligneous acid (also called wood vinegar). While syngas and biochar have well-established applications, pyroligneous acid, remains underutilized, with its agricultural potential still being explored.
This study investigates the properties and composition of pyroligneous acid obtained from the pyrolysis of mixed wood biomass, abundant in Mediterranean agriculture. The biomass was pyrolyzed at 500 °C in a continuous-feed cylindrical reactor at the Euthenia Energy Center (Puente Genil, Spain). For comparison, a commercial organic herbicide was also used. Physical properties (pH, electrical conductivity, density, and dry residue) were measured, while elemental composition (carbon and nitrogen) was determined using a TOC analyzer. Nutrients, micronutrients, and toxic elements were quantified via ICP-OES, and organic molecular composition was assessed using GC/MS.
To evaluate its potential agronomic use as herbicide, germination tests were conducted with Lepidium sativum seeds exposed to varying pyroligneous acid concentrations (0%, 25%, 50%, 100%). Preliminary results reveal the absence of persistent contaminants and significant reductions in seed germination, highlighting its potential as a natural herbicide. Current field trials aim to confirm these findings under real-world conditions. This research demonstrates a pathway for agricultural waste valorization, aligning with circular economy principles and promoting sustainable agricultural practices.
Acknowledgements: This study received support of the Projects RES2SOIL (PID2021-126349OB-C22) and RICE4CHANGE (grant TED2021-130964B-I00) funded by the Spanish Agency of Research (MCIN/AEI/10.13039/501100011033) and the European Union (Next Generation EU/PRTR funding). We also appreciate the support from the Junta de Andalucía, the EU (EAFRD), and the AEI association through the Operative Group Resioliva (agreement GOPO-CO-23-0004). Euthenia Energy Center is acknowledged for its collaboration in this study.
How to cite: Pérez-Dalí, S. M., Sánchez-Martín, Á., Márquez-Moreno, J., Rodríguez-López, C., and de la Rosa, J. M.: Valorization of pyroligneous acids from agricultural waste: Assessment of their potential use as organic herbicide, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4018, https://doi.org/10.5194/egusphere-egu25-4018, 2025.
The adequate quantity and quality of organic matter in soil is a fundamental criterion for nutrient management practices that meet today's challenges. In Hungary, a significant decline in soil organic matter content has been observed in many areas over recent decades. Adequate replacement is problematic for many farmers due to decreasing livestock populations and increasing environmental challenges. On the other hand the large quantities of manure generated during intensive poultry farming cannot be applied directly but, when fermented and supplemented, it can be spread effectively, offering an excellent solution for enhancing the organic matter and nutrient content of the soil.
In our studies, we examined the effects of fermented and pelletized poultry manure products in soil incubation experiments under varying water capacities on meadow chernozem soil. The experiments were conducted for one month. Treatments were terminated weekly to provide continuous information on the processes occurring in the soil. At the conclusion of the experiment, soil samples were taken from two depths in the pots, and after appropriate sample preparation, the pH of the samples was measured using electrochemical methods, while the ammonium and nitrate nitrogen contents were determined by photometric methods.
Our results indicate that the applied products did not significantly affect the soil pH in the tested layers, regardless of the water capacity levels. Compared to the control, all the tested products increased both the ammonium and nitrate contents of the soil. The increase in nitrate concentration exceeded the increase in ammonium content across all treatment combinations. It was found that the amount of ammonium-N in the different soil layers varied less than the nitrate concentration, and the levels of moisture availability also slightly influenced the quantitative relationships and ratios of the nitrogen forms produced.
Compared to the absolute control, nitrate concentration was four times higher, and ammonium concentration was twice as high in the soil layers. Among the nitrogen forms, nitrate was dominant. The positive effect of the product on the soil’s readily soluble and plant-available nitrogen supply was statistically demonstrated.
Acknowledgements: The research presented in the article was carried out within the framework of the Széchenyi Plan Plus program with the support of the RRF 2.3.1 21 2022 00008 project.
How to cite: Nagy, P. T., Magyar, T., and Tóth, F. A.: Investigation of the effects of poultry manure-based nutrient substitutes on soil inorganic nitrogen forms in a soil incubation experiment, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6506, https://doi.org/10.5194/egusphere-egu25-6506, 2025.
Drought and the continuous depletion of soil organic matter represent increasingly critical global challenges. These factors have emerged as the primary constraints on agricultural productivity. Over recent decades, drought-induced crop failures have resulted in considerable economic losses for farmers. Addressing this issue necessitates innovative approaches, compelling researchers to develop and implement effective solutions to mitigate these impacts and ensure their applicability in modern agricultural practices.
The aim of our study was to explore the utilization of chicken manure, a byproduct of intensive poultry farming often classified as hazardous waste. By incorporating supplementary materials designed to enhance soil organic matter and influence mineralization processes favourably, we sought to transform this waste into composite products with potential agronomic benefits.
An experiment was set up to study the effects of composites made from superabsorbent polymers and organic manure in an apple (Malus domestica Borkh. 'Pinova') orchard at the experimental site of the University of Debrecen in Pallag (47°25′28″ N, 21°38′31″ E). The trees were planted in 2011 on M9 rootstock, with a row spacing of 4 m and a tree spacing of 1 m, trained to a 3.5 m tall slender spindle.
In our experiments, we added superabsorbent polymers (one is synthetic and another is organic) (S1; S2 and B1;B2) their mixture (BS1; BS2) the fermented chicken manure at two different dosages and evaluated their impact on soil parameters. The findings were compared against a control group (K) and treatments using only chicken manure (KNEX).
Soil analyses were conducted at six-week intervals to evaluate the effects of the applied treatments. The results revealed that the composite products significantly increased soil organic matter content compared to the control.
Our findings also demonstrated that these composite products enhanced soil organic nitrogen levels over time and promoted favourable mineralization processes. In brown forest soils, characterized by low nutrient retention capacity and a sandy texture, nitrate concentrations in the topsoil ranged between 140 and 170 mg/kg following treatment. The treatments applied significantly affected the soil organic carbon content, especially from the second year of application onwards. Moreover, it was found that the applied composite treatments significantly increased soil organic nitrogen content compared to both the control and the basic product treatment (KNEX).
These findings underscore the potential of these composite products to substantially improve mineralization processes and enhance water retention, particularly in soils with low nutrient availability and limited organic matter content. Furthermore, the development of an integrated water and nutrient management system is imperative. Such a system should combine water-saving irrigation techniques with optimized nutrient management strategies, placing an increased emphasis on the replenishment of soil organic matter to ensure sustainable agricultural productivity.
Acknowledgements: The research presented in the article was carried out within the framework of the Széchenyi Plan Plus program with the support of the RRF 2.3.1 21 2022 00008 project.
How to cite: Tóth, F., Magyar, T., and Nagy, P. T.: Effects of organic composite products on soil organic matter and nitrogen forms in an apple orchard, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12555, https://doi.org/10.5194/egusphere-egu25-12555, 2025.
The global reliance on mineral fertilizers (MF) has raised significant concerns regarding their environmental and economic drawbacks, including soil degradation, water contamination, greenhouse gas emissions, and the unsustainable use of non-renewable resources. As the urgency to develop sustainable agricultural practices grows, there is increasing interest within both the scientific and agronomic communities to explore viable alternatives to conventional MF. Among these, organic amendments such as biochar and hydrochar (HC) have garnered attention due to their potential to improve soil physical and chemical properties while maintaining or enhancing crop yields. Despite the growing body of literature comparing the impacts of mineral and organic fertilizers on soil properties and crop performance, critical knowledge gaps remain with respect to their effects on the abundance and diversity of soil microorganisms. Soil microbial communities are crucial for ecosystem functioning, influencing nutrient cycling, soil health, and plant productivity. To address this gap, this study employs a metagenomic approach to evaluate both the short- and long-term impacts on microbial diversity indices and their relative abundance in soils treated with conventional MF and HC amendments. Thus, a 330-day greenhouse pot experiment was conducted in which sunflower plants were cultured on soils amended with two different application rates of MF and HC (3.25 and 6.5 t ha⁻¹), standardized based on the total applied nitrogen content. Additionally, unamended soils were included as controls. The performance under well-irrigated and water-deficit conditions was assessed.
After 77 and 330 days of cultivation, soil samples were collected from the topsoil (0-15 cm) for high-throughput ITS and 16S rRNA sequencing, followed by bioinformatic analyses. For each treatment, relative abundances and alpha-diversity were determined by calculating richness indices, including observed OTUs, Chao1, Abundance-based Coverage Estimator (ACE), and Shannon and Simpson diversity indices. Additionally, beta-diversity was assessed using Bray-Curtis distance to create the distance matrix between samples and generate the NMDS (non-metric multidimensional scaling).
Significant differences in abundance and alpha-diversity indices (richness and diversity) were observed between treatments both in the short and long term. The NMDS plots also allowed differentiation of treatments. However, the short-term results were significantly attributed to the application of HC. The results after 77 days suggested that, at high application rates and under both irrigation conditions, HC promoted greater bacterial richness and diversity than a similar nitrogen dose with MF.
Regarding fungal richness analysis, whereas HC treatments did not differ significantly from their respective nitrogen-equivalent MF treatments under well-irrigated conditions, they exhibited the lowest values under water-deficit conditions. In contrast, regardless of the irrigation condition, among the treatments, amendment of HC displayed the lowest fungal diversity. These results indicate an increased quantity, richness, and diversity of bacteria in HC-treated soils, which compete with fungal community development, leading to more uniform fungal communities dominated by a few groups.
How to cite: Knicker, H. and Moreno Racero, F. J.: Unveiling Soil Microbial Diversity: Metagenomic Insights into Mineral and Hydrochar Fertilization, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16610, https://doi.org/10.5194/egusphere-egu25-16610, 2025.
Soil degradation caused by climate change leads to unfavorable conditions for soil and crop growth in many countries. Therefore, the use of soil organic amendments (OSAs) are promoted for crop growth and increase fertility in soils. A popular soil organic amendment is biochar which is known for being a good strategy for agriculture to increase sustainability and health of soils. Although great effort is conducted to reveal the combined effect of different biochar application forms to soils on the chemical composition of soil organic matter and plant growth, there is still a lack of understanding in terms of how those practices affect the N cycling and associated biochemical processes. Therefore, in this work we aim to characterize the fate of nitrogen added to soils amended with fresh, aged, and co-composted biochar and cultivated with Lactuca sativa L. var. Therefore 15N-enriched fertilizer was used and the partitioning of the 15N isotope between soil, root and shoot of lettuce plants was measured and related to soil properties, soil organic matter composition, microbial respiration and plant growth. This study explores the multiple positive and negative interactions between different types of biochar addition as soils organic amendments and plant physiological traits. Thus, through soil organic amendments not only greater crop performance can be achieved but also it is key to build knowledge on the relations among soil chemical composition and plant growth to optimize health in European soils.
Acknowledgements: Funded by the European Union. Grant agreement No. 101059546, María Rocio Reinoso, Laura Gismero Rodríguez and Andreas Lücke are thanked for their technical help in the laboratory.
How to cite: García Rodríguez, Á. F., Šolić, M., Moreno Racero, F. J., Maletić, S., Bol, R., Gross, A., Glaser, B., and Knicker, H.: Evaluation aging of biochar application to deficient N soils on their N cycling using 15N isotope tracer, plant growth and soil biochemical parameters, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10003, https://doi.org/10.5194/egusphere-egu25-10003, 2025.
In the Mediterranean region, olive plantations are often located on slopes. These sloping soils are typically less fertile for many crops due to high erosion and increased water drainage rates. However, olive trees, like vineyards and other fruit plantations, thrive in these conditions, making such sites common throughout the Mediterranean basin. Interrow spaces are frequently utilized to test various land management practices and study changes in soil organic matter, erosion, and microbial and molecular diversity. This approach is exemplified by the study plots in this work, located in an olive orchard in southern Spain.
We collected soil from an olive orchard with an 11% slope located in Southern Spain (Benacazón, Seville). The study aims to examine soil organic matter and microorganisms abundance along the slope under two soil management practices: conventional tillage (CT) and natural cover (NC). Additionally, soil from the tree line, treated with herbicide (TL-Herb.), is also included. To account for the effect of seasonality, four sampling campaigns were conducted between autumn 2022 and summer 2023. Phospholipid fatty acid (PLFA) and enzymatic activity analyses were performed to investigate microbial profiles and their relationship with organic matter content along the slope.
With increasing temperatures, we expect to observe a decrease in total microbial biomass and lower F/B ratios. Regarding differences due to land management, we anticipate that NC plots will exhibit the highest microbial biomass and greater total fungal biomass compared to CT and TL-Herb soils. Additionally, we expect stress indicators (saturated/monounsaturated fatty acid ratios) to increase during the driest season, coinciding with the lowest microbial biomass abundance. Our main hypothesis is that plots with natural cover will have higher organic matter (OM) content and total microbial biomass. We also expect to observe differences in the microbiome between the upper and lower parts of each plot, with higher microbial biomass in the lower areas due to the runoff of water and nutrients along the slope. These results will contribute to a better understanding of seasonal shifts in microbial profiles under these land management conditions.
Keywords: microbial profiling, soil management, sustainable agriculture
How to cite: Gismero Rodríguez, L., Knicker, H., and Valverde, A.: Chronosequence study of soil microbial communities from an olive orchard through PLFA profiling, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19555, https://doi.org/10.5194/egusphere-egu25-19555, 2025.
Biochar is a carbon-rich material commonly used as a soil amendment but also has been considered as a potential peat substitute in plant growing substrate in horticulture. However, its impact on soil or substrate quality largely depends on its chemical composition and physical properties that are defined by the production conditions and the feedstock. Commonly, pyrolysis of green waste leads to an accumulation of salt which can lead to an increase of the alkalinity and salinity of the biochar and thus of amended soils and gardening substrate. Often, this is associated to negative impacts on seed germination and plant growth. In order to overcome this problem and assuming that the high alkalinity is caused by high cation contents, we hoped that plant performance can be improved by salt removal Therefore, an experiment was designed to test whether consecutive water washing of two types of highly alkaline biochars enhanced their quality as a plant growing substrate. Whereas the first biochar derived from derived from tomato greens (TB) rich in Sodium, the second was produced from vineyard (VB) pruning residues which were rich in Ca. The pH, elemental composition and ionic contents of the biochars were monitored as a function of washing time. Subsequently, the impact of washing on plant performance was tested performing a greenhouse pot experiment during which tomato plants were grown on a mixture of 40% biochar and 60% gardening substrate. The results show a notable reduction of the pH of the substrate after the washing treatments, leading to improved germination, growth, and biomass weight of the tomato plants. We observed further that high sodium concentrations in the biochar have a stronger negative impact on plant growth than calcium. This work demonstrates that the feasibility of peat substation in growing substrates by some biochars previously considered practically unusable, can be enhanced through simple and relatively inexpensive water washing: This research opens up the possibility of recycling not only of pruning residues but also green residues produced during tomato cultivation as valuable substitute for peat in plant growing substrates in horticulture or gardening, promoting the circular economy and closing the carbon cycle.
How to cite: García de Castro Barragán, J. M., García Rodriguez, Á. F., and Knicker, H.: Removal of Salts from Biochar Used in Growing Substrates Improves Germination and Growth of Tomato Seedlings, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19669, https://doi.org/10.5194/egusphere-egu25-19669, 2025.
Posters virtual: Fri, 2 May, 14:00–15:45 | vPoster spot 3
EGU25-430 | ECS | Posters virtual | VPS15
Impact of hedgerows on the improvement of soil characteristics and vegetation diversity in the semi-arid agricultural landscape of SpainFri, 02 May, 14:00–15:45 (CEST) | vP3.2
The loss of ecosystem services in semi-arid climate is closely linked to the rise of intensive agriculture and the disappearance of landscape elements that have served as buffer areas for hydrological processes and biodiversity over the last decades. As a response, environmental and agricultural policies and initiatives are now being implemented to restore these landscape elements and preserve those that remain in agricultural landscapes. Hedgerows are linear landscape elements that provide several ecosystem services. However, this positive impact varies depending on hedgerows’ characteristics and location.
This study analyses vegetation diversity and its impact on soil properties in eight hedgerows in Southern Spain's Cordoba province. To carry out this, 10m sections were defined in each hedgerow, considering two zones for soil sampling (inside the hedgerow, and within the agricultural field near it, hereafter outside the hedgerow). The evaluation of vegetation consisted of the identification of species of interest in terms of diversity, a general description of the current status of the hedgerow, and a floristic composition and dendrometric variables recording. The analysis of soil properties encompasses samples from different shallow depths (0-5 and 5-10 cm, or only 0-10 cm), and it included pH, soil hydraulic conductivity, bulk density, stability of aggregates, soil respiration by microorganisms, soil organic carbon and extractable phosphorus.
74 species were identified in total, with a high variability of the number of species recorded in most of the hedgerows, where 58% of the identified vegetative species appeared only in one of them, showing the relevance of this vegetative element in the preservation of vegetative species. Significant differences between inside and outside were obtained in all soil properties, except in extractable phosphorus and pH. Soil aggregate stability and organic carbon reached average values of 424.3 g kg-1 and 3.0% inside, versus 265.8 g kg-1 and 1.4% outside, respectively. There was a large variability in some of these properties among different hedgerows. For example, soil respiration varied from 229.7 to 1936.1 mg CO2 kg-1 day-1 and 117.9 to 561.7 mg CO2 kg-1 day-1 inside and outside the eight hedgerows, respectively. This contribution highlights many variables to be considered in hedgerows’ assessments and their complexity, such as the moment of establishment, current management of neighbouring plots, and state of conservation of the own hedgerow.
Acknowledgement: This work was funded by the Spanish Ministry of Science and Innovation (project PID2019-105793RB-I00), financial support from the European Union’s Horizon 2020 under the project SCALE (EUHorizon2020 GA 862695), and a predoctoral fellowship for the first author (PRE2020-093846).
How to cite: Muñoz, J. A., Guzmán, G., Montoliu, J., Hayas, A., Ramos, A., López, M., Mora, J., and Gómez, J. A.: Impact of hedgerows on the improvement of soil characteristics and vegetation diversity in the semi-arid agricultural landscape of Spain, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-430, https://doi.org/10.5194/egusphere-egu25-430, 2025.
EGU25-14207 | ECS | Posters virtual | VPS15
The role of temperature and duration of pyrolysis on the properties of rice husk biochar and its environmental implicationsFri, 02 May, 14:00–15:45 (CEST) | vP3.3
Husks are a common agricultural waste in Indonesia, often discarded or burned, leading to environmental pollution and waste of resources. Therefore, this study proposes an innovative approach to optimize biochar production from rice husks. By determining the optimal pyrolysis temperature and duration, the research aims to produce the highest quality biocharThe pyrolysis temperatures tested were 400°C, 450°C, 500°C, and 550°C, with durations of 30 minutes, 45 minutes, 60 minutes, 75 minutes, and 90 minutes, respectively. The physical and chemical properties of the biochar such as pH, element content, cation exchange capacity (CEC), and biochar yield, were evaluated. An environmental impact assessment was conducted using the ReCiPe 2016 Endpoint H method, integrating life cycle assessment (LCA). The results revealed that a pyrolysis temperature of 550°C for 60 minutes enhanced carbon stability, pH, and nutrient retention. Additionally, the ideal pyrolysis duration significantly improved the biochar’s surface properties. According to the LCA analysis, the biochar produced shows great potential for soil improvement and environmental benefits, including the reduction of greenhouse gas emissions. This research provides a new framework for balancing biochar quality with its environmental impact and promotes sustainable agricultural waste management as part of a global effort to combat climate change.
How to cite: Wahyuni, T., Ngadisih, N., Purwantana, B., Martini, T., Susilawati, H., Meidaliyantisyah, M., Dewi, R., Maftukhah, R., Alfayanti, A., and Sasongko, N.: The role of temperature and duration of pyrolysis on the properties of rice husk biochar and its environmental implications, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14207, https://doi.org/10.5194/egusphere-egu25-14207, 2025.
EGU25-20225 | ECS | Posters virtual | VPS15
Fertilizer efficiency and induced chitinase activity of frass versus frass biochar amended to soilFri, 02 May, 14:00–15:45 (CEST) | vP3.4
Insect production of “black soldier fly” (BSF) larvae is an efficient and sustainable method to convert residual biomass into useful products. A byproduct from insect production, consisting of larval excrement, residual feed and larval exoskeletons, known as “frass,” contains essential macro- and micronutrients and can be advantageously used as fertilizer in agriculture. In addition to nutrients, frass may also contain plant biostimulants and beneficial microorganisms that may have pathogen suppressive effects. However, another potential value enhancement of frass is converting it into biochar via pyrolysis for carbon sequestration. In this study, we compare the effects of frass and the corresponding frass biochar on growth and nutrient uptake by wheat. In addition, we investigated the effect on chitinase activity as an indicator of the potential pathogen suppressive effects of frass compared to frass biochar. A pot experiment with wheat comparing the fertilizer efficiency of frass and frass biochar showed that frass was an efficient P fertilizer, resulting in comparable yields as to the NPK treatment given that N fertilizer was co-applied. In comparison, frass biochar also increased yields compared to the negative control, but not to the same extent as the raw frass. In an additional rhizobox setup, zymography was used to investigate the spatial distribution of chitinase activity in the rhizosphere of wheat. Chitinase activity was induced by frass application, but not by frass biochar, suggesting that the potential pathogenic suppressive effect of frass application is annihilated during pyrolysis. Frass could be an efficient biobased fertilizer, but further investigations into the effects on how frass affects the microbial processes in soil are needed. Frass biochar holds the potential for carbon sequestration and may function as a good soil conditioner. However, this might be at the cost of a more valuable product - the raw frass.
How to cite: Bornø, M. L.: Fertilizer efficiency and induced chitinase activity of frass versus frass biochar amended to soil, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20225, https://doi.org/10.5194/egusphere-egu25-20225, 2025.
