Global Change Biology Bioenergy最新文献

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.

Sugarcane straw removal for bioenergy production—especially second-generation ethanol—is shown to be a promising pathway for decarbonization. However, indiscriminate straw removal can negatively affect soil-related ecosystem services (SES), compromising the sustainability of the associated bioenergy production. Here, a comprehensive literature review was conducted to select and quantify the changes in agronomic and environmental indicators affected by low (≤ 1/3), moderate (> 1/3 to ≤ 2/3), and high (> 2/3) straw removal levels and the consequential impacts on eight SES. A quali-quantitative approach was developed to generate an impact matrix that provides the direction of the effects (negative, neutral, or positive) and the associated confidence levels. Overall, the lowest impact on SES occurs under low straw removal with a neutral effect on C storage, nutrient cycling, weed control, greenhouse gas (GHG) mitigation, and provision of food and bioenergy. Water regulation, erosion control, and maintenance of soil biodiversity were the SES most negatively affected by straw removal. Moderate and high levels of straw removal negatively impact the maintenance of SES and compromise the sustainability of sugarcane cultivation areas, except for pest control and soil GHG emission mitigation. Finally, it was also discussed how the negative impacts of straw removal on SES could be mitigated or even reversed through the adoption of best management practices, such as cover crops, organic amendments, biological products (e.g., use of phosphate-solubilizing bacteria and mycorrhizal fungi), reduced tillage, and machinery traffic control. Ultimately, the results of this study can be useful to guide decision-making by farmers, investors, stakeholders, and policymakers toward sustainable bioenergy production that contributes to a low-carbon economy and climate change mitigation.

The presented research is focused on evaluating the influence of adding clinoptilolite (Z) on the multi-component co-digestion (AcoD) of sewage sludge (SS), citrus waste represented by orange peel (OP) and brewery spent grain (BSG). The experiments were conducted under mesophilic conditions at 37°C in batch mode; 7 series with differing feedstock configurations were performed. The positive effect of Z was shown in each configuration, most strongly with SS:OP:BSG:Z. The production of methane was enhanced by 81%, in comparison to the co-digestion of SS:OP:BSG without Z, reaching 362.4 mL CH₄/g volatile solids (VS). The kinetics was also improved as the methane production rate increased to a similar extent, amounting to 17.3 mL CH₄/g VS d. Moreover, it was observed that the lag phase was shortened and the contents of both limonene and phenols were reduced. The composition of the microbial communities was significantly altered by the addition of Z in AcoD of SS:OP and SS:OP:BSG. Therein, a unique microbiome structure with the highest percentage of unidentified sequences was found. The beneficial effect of Z was multifaceted and related to the reduction of the stress caused by the presence of limonene and phenols as well as the syntrophic relation between the microorganisms.

The torrefaction process for producing biochar from waste biomass has garnered significant attention in recent years. However, economic constraints hinder the broader adoption of this process. One such constraint is the requirement for an inert atmosphere during torrefaction. This study aimed to evaluate the feasibility of torrefying vineyard pruning waste in an oxygen-rich environment. Torrefaction of waste vine shoots was conducted in a fixed-bed reactor, utilizing a carrier gas medium with varying O₂ concentrations (0% to 21%) at process temperatures of 220°C, 250°C, and 280°C. Proximate and elemental analyses revealed that the torrefaction temperature is the key variable influencing biochar yield. Moreover, under mild torrefaction conditions, an increase in the carrier gas O₂ concentration had a lesser impact on product yield compared with process temperature. Thus, it can be inferred that combustion gases and gases generated under mild torrefaction conditions could serve as carrier gases for a more cost-effective torrefaction process. Under oxidative conditions, the total biomass energy recovery was measured at 87.3% ± 1.7% for low temperatures and short torrefaction durations.

Optimizing harvest time has a significant impact on biomass productivity and combustion quality, making it essential to produce sustainable solid biofuel from perennial grasses. This study was conducted to determine the optimum harvest time in tall wheatgrass for the production of solid biofuel in a semi-arid Mediterranean environment by evaluating the effects of six different harvest times (November, January, March, May, July, and September) on biomass yield and combustion quality parameters over two growing seasons. Dry matter yield of the crop steadily increased from the November to May harvest, which approximately coincided with the end of the growing season, but then it was significantly reduced by both the July and September harvests. Additionally, the content of cell wall components (lignin, cellulose, and hemicellulose) and the lignin/holocellulose ratio gradually increased with the progression of maturity and senescence. In contrast, ash, moisture, and mineral (N, P, K, Ca, Mg, S, Si, Cl, Na, and Zn) contents tended to decrease from the May to September harvest. In this regard, the September harvest significantly improved combustion quality by reducing the contents of ash, mineral, and moisture, the risks of slagging, aerosol formation, and corrosion, and increasing the lignin content and lignin/holocellulose ratio, despite causing a 22% yield loss in comparison to the May harvest. These results suggest that the September harvest may be primarily preferred for the sustainable solid biofuel production from tall wheatgrass in the dry marginal lands of the Mediterranean region.

A crucial point for the ecological transition toward a circular bioeconomy is represented by the utilization of municipal biowaste for novel uses in agriculture. Thus, in vitro and in vivo performance of oxidized biopolymers (Ox BPs) obtained from the organic fraction of municipal waste was evaluated against Rhizoctonia root rot and southern blight of tomato (Solanum lycopersicum L.). Further, the selectivity of these biopolymers was evaluated on young tomato seedlings. Effects of Ox BPs were tested at 100, 1000, and 5000 μg mL⁻¹ in reducing Rhizoctonia solani and Sclerotium rolfsii mycelial growth and decreasing relative infections in tomato. The effective concentrations able to reduce mycelial growth by 50% and 95% (EC₅₀ and EC₉₅) calculated according to logit models and minimum inhibitory concentrations (MIC) were about 434, 4550, and 5000 μg mL⁻¹ for S. rolfsii, whereas it was possible to calculate only EC₅₀ (about 788 μg mL⁻¹) for R. solani. In regard to in vivo experiments, Ox BP at 5000 ppm achieved good reductions for both fungal infections ranging from about 62% up to almost 90%, whereas phytotoxic effects were not detected on tomato seedlings at the 3–4 and 4–5 true leaf stages. To the authors' knowledge, this is the first report about Ox BPs antifungal performance against globally widespread soilborne diseases of tomato without detrimental effects on the host crop. However, further studies are needed to confirm the data; this paper presents a starting point for both an eco-friendly disease management approach and recycling of the organic fraction (organic C) of municipal biowastes within the circular bioeconomy framework in a self-sustainable ecosystem.

Bioenergy from biofuels has the potential to slow growing atmospheric carbon dioxide concentrations by reducing fossil fuel use. However, growing bioenergy feedstocks is a land-intensive process. In the United States, the recent expansion of maize bioethanol has presented some environmental costs, prompting the development of several alternative bioenergy feedstocks. These feedstocks, selected in part for traits associated with ecosystem services, may provide opportunities for environmental benefits beyond fossil fuel displacement. We hypothesized that these bioenergy ecosystems will provide direct climatic cooling through their influence on carbon and radiative energy fluxes (i.e., through albedo). To test this hypothesis, we investigated the potential cooling effect of five current or potential bioenergy feedstocks using multi-year records from eddy covariance towers. Perennial feedstocks were carbon sinks, with an annual mean net ecosystem carbon balance (NECB) of −2.7 ± 2.1 Mg C ha⁻¹ for miscanthus, −0.8 ± 1.1 Mg C ha⁻¹ for switchgrass, and −1.4 ± 0.7 Mg C ha⁻¹ for prairie. In contrast, annual rotations were generally carbon sources, with an annual mean NECB of 2.6 ± 2.4 Mg C ha⁻¹ for maize-soy and 3.2 ± 2.1 Mg C ha⁻¹ for sorghum-soy. Using maize-soy as a baseline, conversion to alternative feedstocks increased albedo, inducing further cooling. This effect was strongest for miscanthus, with −3.5 ± 2.0 W m⁻² of radiative forcing, and weakest for sorghum, with −1.4 ± 1.4 W m⁻². When feedstock effects on carbon and albedo were compared using carbon equivalents, carbon fluxes were the stronger ecosystem effect, underscoring the role of perennial species as effective carbon sinks. This work highlights the impact of feedstock choice on ecosystem processes as an element of bioenergy land conversion strategies.

Understanding carbon (C) storage in different soil-sized fractions of perennial bioenergy crops enhances our knowledge of how these crops contribute to long-term soil organic carbon (SOC) storage, with positive implications for mitigating climate change through C sequestration. However, the extent to which perennial bioenergy crops contribute C in different soil-sized fractions remains unclear. Hence, this study investigated SOC contents under perennial bioenergy crops of Miscanthus (Miscanthus × giganteus L.), willow (Salix miyabeana L.), switchgrass (Panicum virgatum L.), and a successional site. We also quantified the C contribution of the bioenergy crops to different soil-sized fractions using the δ¹³C natural abundance technique. After 12 years of cultivation, SOC contents to 30 cm depth increased by 2.5% and 3.1% in willow and Miscanthus, respectively, but decreased by 3.7% in switchgrass compared to baseline SOC data. SOC stocks ranged from 5686 to 7002 g C m⁻² and were higher (p ≤ 0.050) in the successional site compared to switchgrass and willow, but not Miscanthus. Unlike switchgrass and willow, Miscanthus maintained SOC stocks comparable to the successional site even with annual biomass harvest. This implies that the ability of perennial bioenergy crops to influence SOC storage similar to regrowth vegetation on marginally productive cropland depends significantly on the crop species. Additionally, Miscanthus contained higher (p ≤ 0.013) SOC in micro-sized and silt + clay fractions at 20–30 cm depth compared to the 0–10 and 10–20 cm depths and contributed the most C in all three soil-sized fractions compared to switchgrass and willow. Our findings suggest that among the three bioenergy crops, Miscanthus has the greatest potential for long-term C storage and stabilization in deeper soil depths on marginally productive croplands. This holds true even with annual biomass harvesting and the absence of fertilization, making Miscanthus a valuable contributor to climate change mitigation.

The impacts of plastic, including carbon emissions and plastic pollution, have significant negative impacts on human well-being and the environment. Recent research suggests that these impacts could be mitigated by using biomass to create products with lower carbon emissions or that reduce pollution through biodegradation or composting. As the scale of the plastic problem is substantial, the amount of biomass required for mitigation could be large. Biomass may have benefits, but it also has risks, including the potential to cause significant land-use change. Land-use impacts are widely acknowledged in the literature on plastic mitigation but are often downplayed with assumptions that changes in policies, behaviors, agricultural productivity, and technology can ameliorate the most negative impacts. This paper reviews the assumptions made about land use in the literature on biomass-based plastics and plastic alternatives. Current studies generally make optimistic assumptions about land-use change or have limited ability to account for land-use change impacts. These assumptions, including technological and agricultural advancement, along with idealized feedstock sourcing, minimize potential land-use impacts. This paper demonstrates how reasonable projections based on the literature could require a considerable amount of biomass, equivalent to a 7%–13% increase in global crop demand in 2040. Further research investigating projections for biomass use and the assumptions in these estimates is required to better understand potential land-use impacts from bio-based plastic substitutes. This research is important for informing emerging policies, including the UN Treaty on plastic pollution. Establishing criteria and thresholds for the sustainability of bio-based alternatives, as well as identifying potential negative outcomes, will be crucial to avoid setting out on a path with significant unintended and potentially unavoidable consequences.

Climate change threatens long-term soil health because of increased severity and frequency of drought periods. Applying biochar to soils before a drought can increase non-biochar soil carbon (C) and water storage over the long term and sustain crop yield. However, the on-farm benefit of buried solid biochar and applied liquid biochar at low rates remains uncertain. This study examined the effects of two novel biochar-based soil amendments on soil C, water storage and crop yield. The biochar-based amendments included a biochar reactive barrier (RB) made by layering wood-based biochar, straw mulch and cow manure into a series of open surface trenches, and a liquid biochar mineral complex (BMC) applied twice, at low rate (200 kg ha⁻¹) to one side of RB (fertilised area), while the other side of RB received no treatments (non-fertilised area). Moisture concentration within the RB ranged from 6.76% up to 56.68% after large rainfall, more than double the surrounding soils and gradually started migrating from the RB outwards. Soil within 50 cm distance of the RB showed a 24.5% increase in non-biochar soil C compared with soil at 600 cm distance of the RB, 2.54% versus 2.04%, respectively, in the non-fertilised area, which was supported with lowering soil microbial activity. Pasture yield increase was associated with liquid BMC fertiliser rather than proximity to the RB. Pasture yield was 44% higher in the fertilised area compared with the non-fertilised area 27.89 t ha⁻¹ versus 19.31 t ha⁻¹. Approximately 158 kg CO₂e was removed from the atmosphere for each cubic meter of RB and an annual removal of 150 kg CO₂e ha⁻¹ was estimated by liquid BMC application. Income earned by increased yield was still profitable even though applied liquid BMC could cost between USD 400–520 ha⁻¹ including shipping costs. Overall, our study suggested biochar-based RB and BMC fertilisers can effectively increase soil moisture retention while building non-biochar soil C storage in the surrounding soil. The adoption of biochar-based techniques has the potential to improve drought resilience while increasing soil C in wide range of non-irrigated cropping systems.