Global Change Biology Bioenergy最新文献

Plagiomnium acutum has a high value of landscape application and medicinal value, but there is a lack of related research on propagation and cultivation techniques. The deadwood substrate has rich nutrients and superior water retention properties, which will be conducive to promoting the growth of moss. Nevertheless, the underlying mechanisms by which deadwood influences moss growth are not yet fully unclear. In this study, we pulverized deadwood from five decay classes of Pinus massoniana into three distinct particle sizes. Through a pot experiment, we investigated the effects of decay class and physicochemical properties on the growth and physiology of Plagiomnium acutum, aiming to identify the most suitable growth substrate. The results indicated that both the decay class and particle diameter of deadwood significantly affect the substrate's physicochemical characteristics and the growth indexes of P. acutum, with the decay class exerting a more pronounced effect. The water-holding porosity, water-holding capacity, total nitrogen, total phosphorus, total potassium and lignin content of the substrate positively affected the growth of P. acutum, while the bulk density, void ratio, total carbon, carbon-to-nitrogen ratio, condensed tannin content and cellulose content had negative impacts. A comprehensive evaluation using a fuzzy membership function indicated that deadwood with higher decay classes (IV and V) was more conducive to the growth of P. acutum. Specifically, substrates from decay class IV with particle sizes of 10–20 mm provided the most favorable conditions for P. acutum and were recommended as the optimal cultivation substrate. The results of this study provide theoretical basis and technical support for the propagation and cultivation of P. acutum, and provide a foundation for further development of the industrial, pharmaceutical and environmental biotechnology potential of P. acutum.

In emerging markets, investment costs tend to be associated with uncertainty, especially if the investment is policy driven. Globally, nations have agreed to reduce greenhouse gas emissions to keep the temperature increase below 1.5°C by 2100. Australia faces challenges in achieving its Paris Agreement Nationally Determined Contributions and Agenda 2030 commitments, mostly given the extraction profile of its economy. Introducing renewable carbon from forest residues in the niche markets could increase the competitiveness of the forest industry not only in terms of reduced energy costs but also in terms of ‘greening’ the primary product. Growing interest in the bioenergy market, linked with large volumes of available biomass feedstocks including forest residues, presents opportunities in Australia. Yet, ambiguity about costs and concerns about biomass supply throttle the investment potential. This paper aims to estimate a range of forest residue costs along the supply chain for the Australian market by projecting the biomass supply costs from a mature bioenergy market onto it using a benchmarking process reinforced by expert opinion. A three-round Delphi method in which experts indicated direction and range of costs along the forest biomass supply chain revealed that roadside costs of forest residues (other than stumps), and biomass transportation costs, are lower than or equal to and equal to or higher than, the EU costs respectively. Experts ranked investment and supply-side support as priority areas for the development of forest bioenergy in Australia. The expert estimations of forest residue cost ranges along the supply chain offer the first layer for framing a national policy for forest bioenergy within the broader bioeconomy.

Switchgrass (Panicum virgatum L.) is a prominent bioenergy crop with robust resilience to environmental stresses. However, our knowledge regarding how precipitation changes affect switchgrass photosynthesis and its responses to light and CO₂ remains limited. To address this knowledge gap, we conducted a field precipitation experiment with five different treatments, including −50%, −33%, 0%, +33%, and +50% of ambient precipitation. To determine the responses of leaf photosynthesis to CO₂ concentration and light, we measured leaf net photosynthesis of switchgrass under different CO₂ concentrations and light levels in 2020 and 2021 for each of the five precipitation treatments. We first evaluated four light and CO₂ response models (i.e., rectangular hyperbola model, nonrectangular hyperbola model, exponential model, and the modified rectangular hyperbola model) using the measurements in the ambient precipitation treatment. Based on the fitting criteria, we selected the nonrectangular hyperbola model as the optimal model and applied it to all precipitation treatments, and estimated model parameters. Overall, the model fit field measurements well for the light and CO₂ response curves. Precipitation change did not influence the maximum net photosynthetic rate (P_max) but influenced other model parameters including quantum yield (α), convexity (θ), dark respiration (R_d), light compensation point (LCP), and saturated light point (LSP). Specifically, the mean P_max of five precipitation treatments was 17.6 μmol CO₂ m⁻² s⁻¹, and the ambient treatment tended to have a higher P_max. The +33% treatment had the highest α, and the ambient treatment had lower θ and LCP, higher Rd, and relatively lower LSP. Furthermore, precipitation significantly influenced all model parameters of CO₂ response. The ambient treatment had the highest P_max, largest α, and lowest θ, R_d, and CO₂ compensation point LCP. Overall, this study improved our understanding of how switchgrass leaf photosynthesis responds to diverse environmental factors, providing valuable insights for accurately modeling switchgrass ecophysiology and productivity.

Harvest time is an important variable that determines the yield of miscanthus biomass, its possible end uses, and the nutrient offtake from the field. Green harvests result in a higher yield and greater nutrient removal from the field. Brown miscanthus harvests, carried out in late winter or early spring, result in lower yields and a lower nutrient offtake, whereby the harvested biomass is better suited to use in combustion. To look at the long-term impact of green harvests on miscanthus, this experiment followed the yield development of two miscanthus hybrids subjected to green and brown harvests over a period of seven years at one site in Southern Germany. The standard commercial hybrid Miscanthus × giganteus (Mxg) was compared with a novel late-ripening Miscanthus sinensis hybrid: Syn55. Average yields of Mxg were 19.9 t ha⁻¹ for green harvests and 13.2 t ha⁻¹ for brown harvests compared to 13.9 and 12.9 t ha⁻¹ for green and brown harvested Syn55, respectively. Yields of Mxg were very different for green and brown harvests; green harvested Mxg had very high nutrient offtake, while brown harvested Mxg had the lowest nutrient offtakes of all treatments. Syn55 showed a less marked difference between green and brown harvests likely due to its tendency to retain its leaves over winter. Syn55 was however not tolerant of a green harvest, with yields of brown harvested stands surpassing the yield of green harvested stands in several years. Although Mxg demonstrated consistently high yields when harvested in October, some signs of yield decline were detected in both hybrids when harvested green, which was due to insufficient carbohydrate relocation. Alternating green and brown harvests are recommended to allow stands to replenish carbohydrate stores and to form a litter layer.

Miscanthus ×giganteus (giant miscanthus), first found as a naturally occurring hybrid, has shown promise as a bioenergy/biomass crop throughout much of the temperate world. This allotriploid (2n = 3x = 57) hybrid resulted from a cross between tetraploid Miscanthus sacchariflorus (2n = 4x = 76) and diploid Miscanthus sinensis (2n = 2x = 38) and is particularly desirable due to its low fertility that minimizes reseeding and potential invasiveness. However, there is limited genetic diversity in commonly grown cultivars of triploid M. ×giganteus and breeding and development efforts to improve and domesticate this crop have been minimal. Here, we report on newly developed M. ×giganteus hybrids compared with the industry standard M. ×giganteus '1993-1780'. Dry biomass yields of new hybrids ranged from 19.5 to 32.4 Mg/ha/year for the fourth growing season, compared with 21.0 Mg/ha/year for M. ×giganteus '1993-1780'. Plant reproductive fertility remained low for all accessions with overall fertility [(seed set × seed germination)/100] ranging from 0.3% to 4.5% for new hybrids compared to 0.4% for M. ×giganteus '1993-1780'. Culm density and height varied among accessions and were positively correlated with increased biomass. Based on compositional analyses, theoretical ethanol yields ranged from 9, 740 to 16,278 L/ha/year for new hybrids compared to 10,406 L/ha/year for M. ×giganteus '1993-1780'. Relative feed value indices were low overall and ranged between 66.0 and 72.8 for new hybrids compared to M. ×giganteus '1993-1780' with 71.3. The genetic diversity of new hybrids, compared with existing cultivars, was characterized using whole genome sequences. Based on pair-wise distances, cluster analysis clearly showed increased diversity of new hybrids compared with earlier selections. These results document new triploid hybrids of M. ×giganteus with enhanced biomass and theoretical ethanol yields in combination with broader genetic diversity and lowreproductive fertility.

Miscanthus × giganteus (miscanthus) is considered a beneficial biomass energy crop because of its carbon (C) sequestration potential and low fertilizer requirements, but few studies in the United States have measured long-term C sequestration of miscanthus on suboptimal agricultural lands over a decadal scale, and none have been conducted in southeast Ohio. The objective of this study was to measure the soil C sequestration on abandoned agricultural land with a miscanthus crop that is harvested annually, the long-term changes in plant and soil nitrogen (N), and the photosynthetic capacity in the tenth year of growth. This study was conducted over a 10-year period from 2013 through 2023. A significant amount of C was accumulated in the soil (p < 0.05) and the mean C sequestration rates were 0.83 and 1.37 Mg C ha⁻¹ year⁻¹ at two different sites. The amount of C accumulated in the miscanthus plots by the tenth year was also greater than soil C in unmanaged grassland soils, but the difference was not statistically significant (p > 0.05). There was no statistically significant change in the amount of N found in soil and plants over 10 years (p > 0.05), but the variability in plant N was greater in some years relative to others. Even though miscanthus was grown without N fertilizers in this study, soil N at 0–30 cm depth was not depleted over 10 years of crop management. The photosynthetic capacity of miscanthus measured in this study indicated that the plants were thriving after 10 years, and C assimilation for growth was consistent with the findings of prior work that evaluated the maximum photosynthetic rates of this species. The combination of significant soil C sequestration, sustained soil N, and high photosynthetic rates has important implications for the sustainability of miscanthus as a biomass crop.

Concerns about climate change and the reliance on fossil fuel reserves have motivated researchers to identify new renewable sources of energy. Biomass holds the potential to replace fossil-derived products with biofuels and bio-based chemicals. Plant-derived lipids are promising sources of biofuels; however, the production of plant oil often leads to the release of massive amounts of carbon dioxide due to deforestation and land-use change. The production of biofuels via plant oils (such as soybean) also competes with food production and in turn, impacts biodiversity. To mitigate these issues, the production of lipids from oleaginous yeasts could be an excellent alternative by incorporating these microbes into biorefineries utilizing agricultural or forest residues. Eventually, these microbial lipids could be potential sources for producing lipid-derived biofuels. However, the current conventional methods for the production and recovery of lipids from oleaginous microbes suffer from economic and ecological challenges that affect its industrial-scale expansion. This review highlights the major economic and environmental bottlenecks for the production of lipid-derived biofuels from oleaginous yeasts. It also provides perspectives on the strategies that could be adapted on economic and ecological fronts to assist the expansion of the production of microbial lipid-derived biofuels at an industrial scale.

The area of land dedicated to growing maize for bioenergy in the United Kingdom is rapidly expanding. To understand how maize production influences soil carbon (C) dynamics, and whether this is influenced by soil type, we measured net ecosystem exchange (NEE) using the eddy covariance technique over the 2021 growing season. We combined the NEE data with C imports and exports to calculate the net ecosystem productivity (NEP) of two maize crops grown for bioenergy in the United Kingdom, one site on mineral soil and the other on lowland agricultural peat. Maize was similarly productive at both sites—gross primary productivity was 1107 g C m⁻² at the site with mineral soil and 1407 g C m⁻² at the peat site. However, total ecosystem respiration was considerably higher from the peat site (1198 g C m⁻²) compared with the mineral soil site (678 g C m⁻²). After accounting for the removal of C in harvested biomass, both sites were net C sources, but C losses were over two times greater from the peat site (NEP = 290 g C m⁻²) than the mineral site (NEP = 136 g C m⁻²). While annual crops may be needed to produce bioenergy in the short term, growing maize for bioenergy in the United Kingdom does not appear to be a viable option for C sequestration over the long term, as it leads to high carbon losses from agroecosystems, especially those on organic soils. Instead, growing perennial bioenergy crops on mineral soils with a low organic C content is a more appropriate option.

Genotyping-by-sequencing (GBS) is a widely used strategy for obtaining large numbers of genetic markers in model and non-model organisms. In crop plants, GBS-derived marker datasets are frequently used to perform quantitative trait locus (QTL) mapping. In some plant species, however, high heterozygosity and complex genome structure mean that researchers must use care in handling GBS data to conduct QTL mapping most effectively. Such outbred crops include most of the perennial grass and tree species used for bioenergy. To identify strategies for increasing accuracy and precision of QTL mapping using GBS data in outbred crops, we conducted an empirical study of SNP-calling and genetic map-building pipeline parameters in a Miscanthus sinensis population, and a complementary simulation study to estimate the relationship between genome-wide error rate, read depth, and marker number. The bioenergy grass Miscanthus is an obligate outcrossing species with a recent (diploidized) whole-genome duplication. For the study of empirical M. sinensis data, we compared two SNP-calling methods (one non-reference-based and one reference-based), a series of depth filters (12×, 20×, 30×, and 40×) and two map-construction methods (i.e., marker ordering: linkage-only and order-corrected based on a reference genome). We found that correcting the order of markers on a linkage map by using a high-quality reference genome improved QTL precision (shorter confidence intervals). For typical GBS datasets of between 1000 and 5000 markers to build a genetic map for biparental populations, a depth filter set at 30× to 40× applied to outbred populations provided a genome-wide genotype-calling error rate of less than 1%, improved accuracy of QTL point estimates and minimized type I errors for identifying QTL. Based on these results, we recommend using a reference genome to correct the marker order of genetic maps and a robust genotype depth filter to improve QTL mapping for outbred crops.

Biofuel can be used to abate greenhouse gas emissions in the transport sector, by replacing fossil fuel. To avoid the problem of competition with food production, the use of abandoned agricultural land (AAL) for production of the feedstock for biofuel has been proposed. AAL has generally low productivity but has also low opportunity costs, and production of perennial bioenergy crops on it can lead to carbon sequestration. A spatially explicit optimization model of biofuel production and transport fuel consumption, applied to Sweden, was used for an analysis of how AAL can alter costs for greenhouse gas emissions abatement. Results show that, compared to the case without AAL, AAL could decrease the costs of reducing greenhouse gas emissions by 29%, for emissions reductions equivalent to 50% of current emissions from gasoline in Sweden. The carbon sequestration from establishing perennial bioenergy crops on AAL is the main driver of the positive results. High carbon sequestration on AAL implies larger emissions reduction for a given volume of biofuel, and the results show that the total biofuel production can be both smaller and larger with AAL. The use of arable land for biofuel production is generally smaller with AAL, but larger at some of the highest analyzed target levels. The low AAL feedstock costs contribute to lower costs of the total biofuel production, which pushes for more total biofuel production and less fuel use reduction and therefore counteracts the reduced use of arable land.