Biochar production via pyrolysis represents a key option for long-term carbon dioxide removal (CDR) and soil amelioration, as recognized in the EC Delegated Act on Permanent Carbon Removals. Scaling up, however, requires biomass production systems that minimize ecological trade-offs while supplying suitable feedstocks. Here, we characterized biochars produced from nine individually processed feedstock samples representing industrial crops (Miscanthus × giganteus, Cannabis sativa, Crambe abyssinica and Sida hermaphrodita) and cultivated wild plant species (Melilotus officinalis, Tanacetum vulgare, Artemisia vulgaris and Dipsacus fullonum). Under standardized laboratory-scale slow pyrolysis at 550 °C, biochar yields (23.8–29.0wt% d.b.) and H/C molar ratios (0.27–0.32) varied within relatively narrow ranges. In contrast, carbon on a dry basis (66.7–84.0 wt%), fixed carbon (53.1-76.4wt%), ash (7.1–25.8wt%) and specific surface area (27–195 m² g⁻¹) varied substantially, whereas carbon on a dry ash-free basis ranged from 87.9 to 94.0wt%. Measured trace-element concentrations were generally low relative to selected EU Fertilising Products Regulation and EBC-Agro limit values; full regulatory or certification compliance was not assessed. Biochar yields and H/C ratios broadly overlapped between the two feedstock categories. These results indicate that a diverse portfolio of individually processed feedstocks can deliver broadly comparable carbon-stability indicators under one standardized conversion process while retaining functional differences among biochars. They support the potential of diversified biomass production systems for flexible biochar supply chains, although defined-mixture and scale-up experiments remain necessary.

Global soils can store approximately 1500 Pg C in the upper meter and about 2344 Pg C within the upper 3 m, making soil organic carbon (SOC) the largest actively managed terrestrial carbon reservoir. Beyond its climate mitigation role, SOC underpins essential ecosystem services-including soil fertility, water regulation, and ecosystem stability-that support resilient agricultural landscapes and the long-term reliability of food production systems. However, discussions of soil carbon sequestration often focus on biophysical potential while overlooking the human and institutional systems that determine whether this potential can be realized. This Perspective therefore introduces the concept of "dual saturation", arguing that the global potential for soil carbon sequestration is constrained not only by biophysical limits of soil carbon stabilization but also by the operational capacity of farmers to implement complex ecological management practices. Biophysical saturation represents the desired restoration endpoint; operational saturation represents a systemic failure condition. The two are mutually exclusive in practice-and together constitute a self-defeating state, since operational saturation prevents soils from ever approaching their biophysical ceiling. Drawing on evidence from agri-environmental policy research and carbon-farming initiatives, the article argues that administrative complexity, regulatory instability, and documentation requirements can reduce participation in soil carbon-enhancing programs despite available incentives. Supporting farmers' operational capacity through stable and low-friction policy environments thus emerges as an essential enabling condition for large-scale soil carbon restoration and for safeguarding the planetary health functions of agricultural landscapes.

While silage maize (Zea mays L.) remains the dominant biogas feedstock crop in Germany, concerns about landscape homogenization and ecological risks have stimulated the search for more diverse energy crops. This study evaluated twelve amaranth genotypes (GT01–12; Amaranthus spp.) in southwest Germany using field experiments combined with biomass composition analysis and laboratory batch biogas assays. In contrast to earlier studies focusing primarily on the cultivar ‘Baernkraft’ (GT04), a broader set of genetic material was examined. Significant differences among GTs were observed for plant density, dry matter yield (DMY), dry matter content (DMC), and biomass composition. The most productive genotypes (GT09 and GT11) exceeded 10 Mg ha−1 DMY, clearly outperforming Baernkraft. However, even these GTs did not reach the ≈28% DMC threshold considered necessary for reliable ensiling. Lignin concentrations ranged from 4.7% to 7.2% of dry matter. Methane concentrations remained relatively stable (54–55%), resulting in an average methane yield of 1788 ± 441 m3 CH4 ha−1 (maximum: 2677.8 m3 CH4 ha−1) across all genotypes and harvest dates. These findings indicate that amaranth may contribute to diversification of biogas cropping systems, although its agronomic and substrate-related performance remains inferior to that of maize under the conditions studied.

ABSTRACT Perennial energy crops (PECs) are increasingly being recommended for cultivation on marginal lands to support the bioeconomy and promote soil restoration, owing to their low input requirements and large potential for soil organic carbon sequestration. However, the effects of the cultivation of PECs on the trade‐offs or synergies among soil functions, and consequently on ecosystem multifunctionality (EMF), remain unclear, hindering large‐scale adoption. We conducted our measurements in a long‐term field experiment that was established a decade ago, where Miscanthus and switchgrass were cultivated alongside a native C3 grass mixture (Cyperus rotundus L. and Setaria viridis L.) as reference to assess the effects of PECs on soil multifunctionality. We assessed 10 ecosystem functions grouped into provisioning, supporting, and regulating services. The results demonstrate that Miscanthus and switchgrass cultivation elevated the overall EMF by an average of 5.29‐fold over the C3 native grass control, with supporting, regulating, and provisioning services increasing by 2.08, 7.27, and 43.98‐fold, respectively. Specifically, the two PECs improved all 10 measured soil functions, with the exception of abiotic stress regulation under switchgrass cultivation. Miscanthus outperformed switchgrass by 41.54% in supporting services and 81.09% in provisioning services, resulting in higher EMF. Moreover, strong positive relationships were observed among the three service categories, indicating that the cultivation of PECs improves EMF consistently without significant trade‐offs. These findings suggest that cultivating PECs on marginal land can simultaneously provide sustainable biomass feedstock and enhance soil health, supporting the feasibility for larger‐scale deployment.

Increasing demand for multiuse crops in the bioeconomy highlights the potential of industrial hemp (Cannabis sativa L.). However, its regional implementation, particularly in Southern Germany, remains limited. This study examines the industrial hemp value web in the Swabian Alb, assessing its agricultural system resilience through a comprehensive framework of 65 indicators encompassing environmental, social, and economic dimensions. Data were collected through 19 in-depth stakeholder interviews (representing a 76% response rate), elucidating value web dynamics and deconstructing the systemic barriers-regulatory, infrastructural, and economic-that inhibit hemp's full potential. The Swabian Alb, characterised by strong research networks and sustainability awareness, exhibited a volatile hemp cultivation area, decreasing by 56.9% to 25 ha in 2024 compared to 2023. Results reveal a sharp divergence in performance: while hemp provides significant public goods through soil improvement and biodiversity support (e.g., pollen provision and insect habitat), it performs poorly in private goods due to high labour intensity, financial risk, and low revenue. The study identifies a critical infrastructural gap in regional fibre processing and a market frustrated by niche demand. We conclude that sustainable development requires shifting the narrative away from the 'miracle plant' myth toward a realistic communication of challenges, supported by targeted policy interventions, consumer education, and secured sales agreements. These findings provide a roadmap for transitioning industrial hemp from a research-driven niche to a resilient bioeconomic staple.

This study examines the urgent issues of water scarcity and limited farmer livelihoods in the Urmia Lake basin. To address these challenges, we apply the Governance, Autonomy, Integration, and Needs orientation (GAIN) methodology. Our participatory approach revealed that farmers prioritised actionable measures for water management, yield improvement, and agricultural efficiency. The resulting action plan focused on concrete covering of earth canals, pumping water with pipes, and establishing a reporting system with weather stations. Farmers also highlighted revenue-focused priorities, such as using foggers and woodchip mulch with alternative fertilisers. The successful implementation of drip and ring basin irrigation systems, along with plastic mulch, demonstrated an average efficiency of 83% and motivated farmers to adopt modern management practices. Through this process, farmers' knowledge and accountability for sustaining the ecosystem were significantly enhanced. Scaling this project to other critical areas within the Urmia Lake basin will be key to ensuring the region's long-term sustainability and restoration, providing a relevant case study for international research on irrigation and drainage that must adapt to the escalating pressures of climate change.

The transition towards a sustainable and circular bioeconomy is among the most pressing scientific and societal challenges of the twenty-first century [...]

Fully cellulose-based mulch materials could provide a structurally simpler alternative to biodegradable polymer-blend films for perennial crop establishment, prompting the question of whether comparable agronomic performance can be achieved. We conducted a proof-of-concept field trial establishing Sida hermaphrodita (L.) Rusby under three treatments in two replicate plots (36 m2 each): (i) a prototype cellulose-based spunlace mulch fleece, (ii) a commercial soil-biodegradable mulch film (‘Samco Bio Black’), and (iii) an unmulched control. Given the low replication (n = 2), results are interpreted as exploratory. At first harvest (9 March 2026), dry matter yields were 0.75, 0.34, and 0.22 t ha−1 for the mulch film, mulch fleece, and control, respectively, while the mulch film reduced weed fresh matter by 87–96% compared with 20–46% for the fleece. The findings identify priorities for further prototype development and support continued research on fully cellulose-based mulch materials for perennial biomass crop establishment.

The loss of biodiversity threatens global environmental stability and socio-economic resilience. The protection of ecosystems and their services through habitat conservation and species preservation requires all stakeholders to assess and disclose their impacts on biodiversity. Higher education institutions (HEIs) play a critical role in this, acting as research centres, educators, sustainability leaders, and stewards of local ecosystems. Although many organizations monitor their carbon footprints, biodiversity and habitat assessments remain underutilized in decision-making, despite their importance in identifying conservation priorities and supporting nature-positive strategies. This study compares insights from a direct, campus-level biodiversity survey (BioBlitz) with those of an indirect, consumption-based, environmentally extended input-output life cycle assessment (EEIO-LCA). While local surveys yield site-specific, actionable data, they often lack systematic coverage and baseline reference conditions. By contrast, EEIO-LCA identifies procurement-related biodiversity pressures but suffers from aggregation and limited ecological interpretability. Integrating these complementary perspectives remains challenging due to mismatches in scale and metrics. We discuss a pathway towards integration through harmonized habitat baselines, improved supplier and regional data granularity, regionalized characterization factors, and hybrid LCA approaches. A staged roadmap that strengthens each method independently, standardizes uncertainty translation, and cautiously tests bridging indicators can guide HEIs towards robust, integrated biodiversity accounting. By contributing our baseline and discussion to the Nature Positive Universities Alliance's common repository of methods and case studies, we can benchmark progress, harmonize data standards (e.g. supplier origin disclosure, monitoring design) and co-create scalable interventions.

The European Commission prioritizes addressing environmental issues like agrobiodiversity loss within a thriving bioeconomy's defossilization. This study investigates eight native European herbaceous flowering wild plant species (WPS) like common tansy ( Tanacetum vulgare L.) and wild teasel ( Dipsacus fullonum L.) as co‐substrates for pellet combustion, aiming for more biodiversity‐friendly bioenergy cropping systems. A long‐term field trial in southwest Germany examined dry matter (DM) yield and biochemical composition's influence on combustion properties for these WPS and two common bioenergy crops, Miscanthus ( Miscanthus x giganteus Greef et Deuter) and Sida ( Sida hermaphrodita L. var. Rusby), over two growing seasons. All eight WPS showed suitable combustion properties, comparable to Sida , with significantly higher ash melting temperatures than Miscanthus . This is largely attributed to elevated calcium (5.6–15.3 mg g −1 DM) and magnesium (0.6–2.4 mg g −1 DM) contents. A consistent WPS biomass composition is suggested by no significant year effect. Additionally, lower SO 2 and HCl fugacity indicated more environmentally friendly combustion than Miscanthus . However, only a few WPS matched Miscanthus's high DM yield (6.0–12.3 Mg ha −1 ). This underscores the need for broader WPS investigation to find effective combined solutions for bioenergy and rural environmental protection.

Shallow arable soils (<35 cm depth) are classified as marginal for common agriculture but may still support biomass production from industrial crops like fiber hemp, which has a low indirect land-use change risk. However, little is known about hemp’s performance under such conditions. Therefore, this study investigated the biomass yield and quality of fiber hemp and other crops on a shallow (<35 cm), stony (>15% stone content), and clay-rich (>50% clay content) soil at 800 m above sea level in Southwest Germany (2018–2021). A randomized field trial tested different row widths and nitrogen (N) fertilization levels to assess low-input options for the given type of marginal land. Across years and row widths, hemp achieved average grain dry matter (DM) yields of 1.3 Mg/ha at a fertilization rate of 40 kg N/ha and 1.6 Mg/ha at 120 kg N/ha (with on average 30.9 ± 1.4% crude fat content across treatments). The average stem DM yields accounted for 5.11 Mg/ha (40 kg N/ha) and 6.08 Mg/ha (120 kg N/ha), respectively. Reduced N fertilization (40 kg/ha) lowered DM yields by up to 16% compared to full fertilization (120 kg/ha), but the effect was not significant and weaker at wider row spacing (45 cm). Additionally, maize reached acceptable DM yields (>17 Mg/ha). These findings suggest that shallow soils classified as marginal require reassessment, as they may offer viable opportunities for sustainable industrial hemp cultivation and contribute to a bio-based economy.

Establishing resource efficient non-food crops on contaminated land by implementing different crop management regimes is gaining attention as a strategy for a sustainable long-term management of polluted soils. Therefore, the current study aims to set-up a technology with enhanced phytoremediation capacity by combining perennial energy crops miscanthus and switchgrass with biostimulants to promote beneficial soil bacteria and fungi, evaluated through field trials on a metal polluted soil. The crops' growth was compared under two different biostimulants treatments and a control taking into account biomass yield, morphological parameters, soil physicochemical and biological properties. The findings demonstrate that biostimulants treatments compared with control positively influenced crop biometric traits and increased biomass yield up to 3 t ha(-) (+54 %) and 9 t ha(-1) (+35 %) for miscanthus and switchgrass, respectively in the second establishment year. Biostimulants treatment HAM (humic acid combined with mycorrhizae) performed best. This biostimulants treatment reduced the metal CaC(l)2-available fraction in both miscanthus and switchgrass plots, with the exceptions of Pb in switchgrass and Cu in miscanthus. This study clearly corroborated that both factors under study, i.e crop type and biostimulants applications have influenced the soil microbiome structure. Compared with the control group, biostimulants HAM treatment increased abundance of Bacillus by 44 % in miscanthus and Candidatus Solibacter by 200 % in switchgrass. In the case of fungi, the biostimulants HAM treatment promoted the relative abundance of Fusarium in the rhizospheres of both miscanthus and switchgrass. Collectively, the findings of this study suggest that selecting the right crop and biostimulants application can modulate the rhizosphere environment, consequently enhancing the effectiveness of phytomanagement technologies.

This Special Issue serves as a timely follow-up to a previous exploration of “Social–Ecologically More Sustainable Agricultural Production” [...]

The capacity of agriculture to withstand or recover from increasing stresses (i.e., resilience) will be continuously challenged by extreme climate change events in the coming decades, altering the growing conditions for crop species. By prioritizing natural processes, agroecology seeks to foster climate change adaptation, boost resilience, and contribute to a low-emission agricultural system. Nineteen different agroecological practices using resilience-related terms and “meta-analysis”, within the subject areas ‘Agriculture and Biological Science’ and ‘Environmental Science’ were addressed, and 34 meta-analyses were reviewed to summarize the state-of-the-art agroecological adaptative strategies applied globally, and the current knowledge gaps on the role of agroecological practices in improving farming system resilience. Two main agroecological strategies stand out: i) crop diversification and ii) ecological soil management. The most frequent diversification practices included agroforestry, intercropping, cover cropping, crop rotation, mixed cropping, mixed farming, and the use of local varieties. Soil management practices included green manure, no-till farming, mulching, and the addition of organic matter. The analyzed studies highlight the complex interplay among soil, plant, climate, management, and socio-economic contexts within the selected agroecological practices. The results varied—positive, null, or negative—depending largely on site-specific factors. Developing and understanding more complex systems in a holistic approach, that integrates plants and animals across multiple trophic levels (feeding relationships, nutrient cycling, and aligning with the principles of a circular economy) is essential. More research is, therefore, needed to understand the interactions between crop diversity and soil management, their impacts on resilience, and how to translate research into practical strategies that farmers can implement effectively.

Industrial crops grown on marginal lands offer a potential source of low-iLUC feedstock for bio-based industries, supporting sustainable bioeconomic development. However, marginal-land-based bioeconomy systems face significant uncertainties at early stages, such as limited data, farmers' hesitancy to adopt novel crops, undeveloped markets and immature technologies. This study implements an integrated multi-criteria framework as a structured, multi-step approach to connect bio-based value chain components and stakeholders in marginal-land-based bioeconomy systems at the research level. The framework was applied within the EU Horizon project MIDAS to identify, evaluate and combine bio-based value chain components, with a case study in the Swabian Alb (southern Germany) demonstrating its potential for designing scalable bio-based value chains tailored to regional conditions. Key findings emphasise the importance of stakeholder collaboration, iterative design processes and context-specific criteria that address technical, economic, social and regulatory aspects. The approach, based on qualitative data and stakeholder input, offers critical insights into the feasibility of biomass-to-product pathways and serves as a foundation for advanced research. Future research needs to focus on expanding data availability, incorporating quantitative methods, and addressing economic and market factors, such as stakeholder willingness to produce feedstocks, to enhance the scalability and robustness of the findings and facilitate the establishment of sustainable bioeconomy systems on marginal lands.

As warm season droughts increase in frequency due to climate change, causing severe yield losses especially among cereal crops, European agriculture is in dire need of adaptation. While agroforestry is widely regarded as a key adaptation measure, little is known on how yield performance is influenced by changing water availability in temperate regions. Therefore, we assessed the yield dynamics of five winter crops (winter wheat, triticale, winter barley, winter pea, and rapeseed) during seven growing seasons (2012 to 2023) in a well-established (since 2007) alley cropping agroforestry trial site in Southwestern Germany. The trial integrated three different agroforestry practices in a randomized block design: (i) willow short-rotation coppice, (ii) walnut trees for nut production, and (iii) diverse hedgerows. The relationship between crop yield and climatic water balance was analyzed using a linear mixed-model. In this unique long-term comparison, we demonstrate that individual alley cropping practices exhibited distinct yield patterns with increased distance to tree rows. In contrast to the willow short rotation coppice, walnut and hedgerows did not evoke significant winter crop yield declines at proximity. While in the walnut plots yields did not significantly vary with distance to tree rows, yields adjacent to hedge rows declined significantly towards the alley center. Moreover, tree rows contributed to stable crop yields under fluctuating water availability in their proximity and up to the alley center on their leeward side while yields significantly varied with changing climatic water balance on the windward side. Our results underline the potential of agroforestry to sustain yields in the face of increasingly variable water availability, further substantiating the contribution of alley cropping agroforestry for farming systems’ resilience to increasingly variable weather conditions. They moreover contribute to planning and policy support for advancing agroforestry as a climate smart solution in temperate regions.

The bioeconomy has been discussed as a key strategy for addressing sustainability challenges, particularly regarding the transition from fossil-based to bio-based systems, in numerous national and supranational strategies and policy documents related to the bioeconomy. However, public understanding of and engagement with the bioeconomy remains limited. This is partly due to the bias of many bioeconomy strategies and policy documents towards technological solutions that tend to overlook the social, normative, and transformative dimensions of systemic change as well as the necessary knowledge. This opinion paper explores the potential of narratives as a means of communicating bioeconomy research in public policy, with the aim of addressing the communication gap between science, policy, and society. When applied in responsible and nuanced ways that acknowledge their embeddedness and context, bioeconomy (policy) narratives can support sensemaking for science communication, improve public understanding, facilitate stakeholder engagement and behavioural change. We argue that such narrative approaches can help to create narrative ‘boundary objects’ that can support more inclusive and participatory processes, enabling the co-creation of transformative knowledge for bioeconomy transitions with stakeholders as active participants. In summary, we highlight several opportunities, as well as limitations and implications, that could inform future work on bioeconomy narratives.

The pretreatment of lignocellulosic biomass such as Miscanthus grown on marginal agricultural land is very challenging and requires severe conditions to fractionate cell wall polymers for further valorization. The current study aimed to determine organic acid-based mild conditions to pretreat contrasting lignocellulosic Miscanthus genotypes for the efficient fractionation of cell wall components, with special focus on hemicellulose extraction. In doing so, five Miscanthus genotypes were subjected to four different acid treatments (sulfuric acid, oxalic acid, malonic acid, and citric acid) in a vertical high-pressure steam sterilizer. The results demonstrated that, among the organic acids, oxalic acid was identified as the most effective pretreatment solvent for hemicellulose separation, whereas citric acid yielded the highest amount of galacturonic acid, varying from 15 to 17 mg mL−1 across genotypes. One best performing genotype was selected for the enzymatic hydrolysis. Overall, M. floridulus genotypes exhibited the optimal quality traits for efficient bioconversion with second best in terms of ethanol production potential.

Using contaminated land to grow lignocellulosic crops can deliver biomass and, in the long term, improve soil quality. Biostimulants and microorganisms are nowadays an innovative approach to define appropriate phytomanagement strategies to promote plant growth and metal uptake. This study evaluated biostimulants and mycorrhizae application on biomass production and phytoextraction potential of four lignocellulosic crops grown under two metal-contaminated soils. Two greenhouse pot trials were setup to evaluate two annual species (sorghum, hemp) in Italy and two perennial ones (miscanthus, switchgrass) in China, under mycorrhizae (M), root (B2) and foliar (B1) biostimulants treatments, based on humic substances and protein hydrolysates, respectively, applied both alone and in combination (MB1, MB2). MB2 increased the shoot dry weight (DW) yield in hemp (1.9 times more), sorghum (3.6 times more) and miscanthus (tripled) with additional positive effects on sorghum and miscanthus Zn and Cd accumulation, respectively, but no effects on hemp metal accumulation. No treatment promoted switchgrass shoot DW, but M enhanced Cd and Cr shoot concentrations (+84%, 1.6 times more, respectively) and the phytoextraction efficiency. Root biostimulants and mycorrhizae were demonstrated to be more efficient inputs than foliar biostimulants to enhance plant development and productivity in order to design effective phytomanagement strategies in metal-contaminated soil.

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