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Marginal land conversion to perennial energy crops can provide biomass feedstocks and climate change mitigation. However, the effect of perennial energy crop cultivation on soil organic carbon (SOC) sequestration and its underlying mechanism in marginal land still remains incomplete. Here, SOC turnover, stability, and its potential sequestration were evaluated based on 10 years of land use change from C3 grass‐dominated marginal land to C4 energy crops Miscanthus and switchgrass cultivation. The naturally occurring 13C signature down to 60 cm depth was used to determine the energy crops‐derived C. Compared to reference marginal land, Miscanthus plantation increased the SOC stock at 0–60 cm depth by 17.8% and 64.3% in bulk and root zone, respectively. Similarly, the SOC stock under switchgrass was also 16.5% and 93.0% higher in bulk and root zone than in reference marginal land, respectively. The higher SOC stock in the root zone of switchgrass relative to Miscanthus was supported by the higher contribution of C4‐derived C to SOC (44.5% vs. 32.4%). The mean residence time of old C was higher under switchgrass than Miscanthus in the bulk zone across 0–60 cm (p < 0.05) but remained the same at 0–20 cm in the root zone. Specific SOC mineralization and temperature sensitivity were lower in soils under Miscanthus and switchgrass compared to reference marginal land. The partial least squares path model revealed that perennial energy crop cultivation enhances soil C stock via increased C4‐derived C input and reduced mineralization. In conclusion, marginal land conversion to perennial energy crops is a win–win strategy for C sequestration to mitigate climate change and support the growing bioenergy sector with biomass supply. [ABSTRACT FROM AUTHOR]

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Miscanthus lutarioriparius is a native perennial Miscanthus species of China, which is currently used as raw material of papermaking and bioenergy crop. It also has been considered as a promising eco-bioindustrial plant, which can offer raw material and gene for the biomass industry. However, lack of germplasm resources and genetic diversity information of M. lutarioriparius have become the bottleneck that prevents the stable and further development of the biomass industry. In the present study, genetic diversity of 153 M. lutarioriparius individuals nine populations was studied using 27 Start Codon Targeted (SCoT) markers. High polymorphic bands (97.67%), polymorphic information content (0.26) and allele number (1.88) showed SCoT as a reliable marker system for genetic analysis in M. lutarioriparius. At the species, the percentage of polymorphic loci [PPL] was 97.2%, Nei’s gene diversity [H] was 0.36, Shannon index [I] was 0.54 and Expected Heterozygosity [He] was 0.56. Genetic variation within populations (84.91%) was higher than among populations (15.09%) based on analysis of molecular variance (AMOVA). Moderate level of genetic differentiation was found in M. lutarioriparius populations (Fst = 0.15), which is further confirmed by STRUCTURE, principal coordinates analysis (PCoA) and an unweighted pair group method with arithmetic mean (UPGMA) analysis that could reveal a clear separation between groups of the north and south of Yangtze River. The gene flow of the populations within the respective south and north of Yangtze River area was higher, but lower between the areas. There was no obvious correlation between genetic distance and geographic distance. The breeding systems, geographical isolation and fragmented habitat of M. lutarioriparius may be due to the high level of genetic diversity, moderate genetic differentiation, and the population, structure. The study further suggests some measure for conservation of genetic resources and provides the genetic basis for improving the efficiency of breeding based on the results of diversity analysis. [ABSTRACT FROM AUTHOR]

Highlights • Multi-criteria decision making model was developed to screen miscanthus for energy breeding. • Energy-related traits of miscanthus include the two aspects of agronomy and quality. • Miscanthus lutarioriparius is most suitable for producing electricity and pyrolysis bio-oil. • Miscanthus floridulus is most suitable for producing bioethanol and biogas. Abstract Biomass is the bioenergy carrier and can be converted to solid, liquid and gaseous fuels. Miscanthus , a plant type with high biomass yield potential, is a promising feedstock source for bioenergy production. However, the current expansion of miscanthus (Miscanthus spp.) production is constrained by a shortage of commercial varieties, especially those suitable for different energy usages and cultivation under adverse environmental conditions. Therefore, breeding or selecting high-biomass-yielding, high quality and stress tolerant miscanthus varieties is essential for the extension of miscanthus for bioenergy production. To effectively select elite germplasms and breed new varieties of miscanthus, it is necessary to establish a scientific evaluation method for analysing their energy potential. In this study, a multi-criteria decision making (MCDM) model was designed to evaluate the potential of miscanthus germplasms as feedstock in four energy usages including combustion for power generation (CPG), pyrolysis for bio-oil production (PBP), fermentation for ethanol production (FEP) and fermentation for biogas production (FBP). The MCDM model was constructed based on 11 sub-criteria indices, which were grouped into agronomic-related and quality-related criteria indices. The agronomic-related criteria indices include dry matter yield, canopy height, stem diameter, tiller number and base diameter/canopy diameter ratio. The quality-related criteria indices include the leaf/stem ratio, moisture content, ash content, cellulose content, hemicellulose content and lignin content. Thirty-eight representative germplasms of miscanthus were evaluated. The MCDM analysis results showed that Miscanthus lutarioriparius (especially the XiangNanDi no. 1 variety) and Miscanthus floridulus (especially A0521) are the best species for CPG/PBP and FEP/FBP, respectively. These results are superior to those calculated by the traditional energy potential assessment method, which showed that Miscanthus floridulus was the most suitable species for CPG, FEP and FBP, especially A0521 and D0624. Moreover, the analysis also indicated that D0505 (M. floridulus) can be used as a suitable parent together with XiangNanDi no. 1 to breed new varieties for CPG and PBP; XiangNanDi no. 1 can be used as an alternative parent for breeding to improve A0521 for use in FEP and FBP. [ABSTRACT FROM AUTHOR]

The composition, cellulose degradability and biochemical methane potential (BMP) of M. sinensis , M. floridulus , Miscanthus × giganteus and M. lutarioriparius were investigated concomitantly at different growth/harvest times during their growing season. For all the four species, there was only a slight change in the compositional content. Meanwhile there was a huge change in the BMP values. At the growth time of 60 days the BMPs ranged from 247.1 to 266.5 ml g −1 VS. As growth time was prolonged, the BMPs decreased by 11–35%. For each species, the BMP was positively correlated to the cellulose degradability with the correlation coefficients (R 2 ) ranging from 0.8055 to 0.9925. This suggests that besides the biomass yield, it is justifiable to consider cellulose degradability when selecting the suitable harvest time for biofuels production from Miscanthus , especially in tropical and subtropical regions where Miscanthus can be harvested twice or more within a year. [ABSTRACT FROM AUTHOR]

Bio-energy production from lignocelluloses biomass has gained a lot of interest in recent years. Miscanthus sp. are high lignocelluloses biomass yielding with relatively high carbohydrate content cultivable on different soils and under climatic conditions. However, the lignocellulosic nature means that cellulose and hemicellulose are cover by lignin network that might limit hydrolysis. In this study, physical pretreatments (size reduction), physiochemical (steam expulsion) and chemical pre-treatments (mild acid and alkaline) were investigated in a view to improve the anaerobic biodegradability of Miscanthus lutarioriparius for biogas production. Prior to the pretreatment and methane potential test, the compositional analyses of M . lutarioriparius was performed in order unveil the carbohydrate (cellulose and hemicelluloses), protein and lignin contents. From these analyses, the maximum theoretical methane potential was estimated. All pretreatments led to solubilisation of organic matter as was evidenced by increase dissolve COD and ammonium nitrogen. There was a positive correlation between dissolved COD and methane yields meanwhile a negative correlation was observed for reducing sugar and methane yields. The achieved methane yields ranged from 121 to 238 ml CH 4 /g VS. Steam explosion, 0.3 M NaOH treatment and 0.5 mm size reduction led to the highest increases in methane yields, which was in the order of 57% with regard to the untreated samples. These improvements resulted in 71% of theoretical methane yield of M. lutarioriparius. Alkaline pretreatment in particular also improve the rate of methane production as was evidenced by the fact that as high 15% of the final methane yield that was achieve on the first day as compared to only 3% for the untreated sample. Indeed, the time to reach 90% of the ultimate methane yield was reduced by 13 days following 0.3 M NaOH treatment. M. lutarioriparius may therefore represent an interesting candidate as a lignocellulosic feedstock for biogas production after suitable pretreatment. [ABSTRACT FROM AUTHOR]

Severe environmental and ecological problems have resulted due to the unharvested Miscanthus lutarioriparius biomass in Dongting Lake, the largest miscanthus production hub in the world. Pyrolyzing the miscanthus biomass to produce biochar is a win–win strategy for abandoned miscanthus biomass utilization and Cd-polluted paddy restoration in Hunan. However, the sorption efficiency of biochar requires improvement by modification. It is theoretically possible that biological modification by fungi and bacteria as well as a modification technique using Fe will increase the Cd sorption capacity. Thus, the current study used two biomass biomodification techniques, FB (fungal decomposition) and BB (bacterial digestion), and one biochar Fe-modification technique (by NH 3 ·H 2 O–FeCl 3), and determined their ability to improve biochar quality. The results showed that the biomass modification by FB and BB increased the Cd sorption capacity of the derived biochar. The Cd sorption capacity of FB-derived biochar (36.4 mg g−1) was significantly greater as compared to BB-derived biochar (30.2 mg g−1) and the unmodified control (14.8 mg g−1). This improvement can be further optimized by Fe-modification, with an average potential of 22.2% (13.5–32.3%). The increased Cd sorption capacity is attributed to (in descending order of importance) the increased amount of ash, specific surface area, amount of alkaline functional groups and phenolic hydroxyl groups, and the pH of the biochar after modification. The Fe-FB-derived biochar pyrolyzed under 650 °C was tested and exhibited the highest Cd sorption capacity, at 64.9 mg g−1. Biomodification of M. lutarioriparius biomass and its subsequent pyrolysis to produce biochar will simultaneously provide economic and ecological benefits. This approach provides a model for the integrated production of food and energy from biomass. [Display omitted] • Biomass modification strongly increases the Cd sorption capacity of biochar. • Fungal decomposition and bacterial digestion are effective modification techniques. • The Cd sorption capacity of biochar can be further optimized by Fe modification. [ABSTRACT FROM AUTHOR]

Abstract: Near infrared spectroscopy (NIRS) has been broadly applied as a quick assay for biological component and property analysis. However, NIRS remains unavailable for in-depth analysis of biomass digestibility in plants. In this study, NIRS was used to determine biomass enzymatic digestibility using 199 Miscanthus samples, which represents a rich germplasm resource and provides for a stable calibration model. The intensive evaluation indicates that the calibration and validation sets are comparable. Using the modified partial least squares method, seven optimal equations were generated with high determination coefficient on calibration (R 2) at 0.75–0.89, cross-validation (R 2 cv) at 0.69–0.87, and the ratio performance deviation (RPD) at 1.80–2.74, which provide multiple options for NIRS prediction of biomass digestibility under different pretreatments. As biomass digestibility is a crucial parameter for biofuel processing, NIRS is a powerful tool for the high-throughput screening of biomass samples in plants. [Copyright &y& Elsevier]