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Miscanthus, a perennial rhizomatous C4 grass, has emerged as a promising lignocellulosic crop. To avoid competition with food crops, marginal lands especially saline–alkaline soil are being recommended to grow Miscanthus across China. However, the challenges such as high cost and low reproduction coefficient associated with the propagation methods are impeding its large‐scale plantation in saline–alkaline soil. In this study, a "two‐steps" propagation method was designed, which was comprised of two phases: (1) seedling cultivation and (2) seedling strengthening. The parameters (substrate composition and plug size) for this method were determined. The optimal substrate composition of the seedling bed for M. sinensis, M. lutarioriparius, and their interspecific hybrids was peat and perlite at a ratio of 3:2, 3:1, and 3:3 by volume, respectively. The seedlings were transplanted into the plugs to deliver robust plantlets. The most appropriate plug size for M. sinensis, M. lutarioriparius, and their interspecific hybrids was 50 plugs (50 cm3/plug), 72 plugs (40 cm3/plug), and 72 plugs (40 cm3/plug), respectively. Three propagation methods, that is, direct sowing of seeds, rhizomes plantation, and "two‐steps" seed‐derived plugs for M. lutarioriparius were compared in saline–alkaline soil over 3 years (2014, 2015, and 2016). The establishment rate of the seeds directly planted was poor (zero). The performance (e.g., biomass yield) of the plants derived from the "two‐steps" seed‐derived plugs was better than that of the plants derived from rhizomes directly planted. Therefore, the "two‐steps" seed‐derived plugs can be regarded as an effective propagation method to upscale Miscanthus cultivation in saline–alkaline soil. [ABSTRACT FROM AUTHOR]

Miscanthus is characterized by high biomass production potential and low input requirements and therefore considered a leading candidate for second-generation energy crops. Because China has limited agricultural land resources, development of its miscanthus-based bioenergy industry must rely on the use of marginal land. This study focuses on the assessment of the production potential of miscanthus on China’s marginal land, which in this context is defined as land presently not used for agricultural production, residential purposes and other social uses. Geographic Information System (GIS) techniques and model simulation are adopted to identify the productive marginal areas for miscanthus and to estimate their biomass and bioenergy production potential. The results show that although a large marginal area of 17,163.54×10 4 ha is available for producing miscanthus, due to the limitation of low winter temperatures and low precipitation levels in some areas, the total suitable marginal area is only 769.37×10 4 ha. The Monteith radiation yield model was used to determine the potential miscanthus yield in Chinese climatic conditions. The simulation gave actual harvestable yield levels on arable land of 18.1–44.2 t ha −1 yr −1 . Taking the environmental stresses of marginal conditions into account then gave an achievable miscanthus yield potential on marginal land of 2.1–32.4 t ha −1 yr −1 (average for the different marginal lands). Based on these achievable yield levels, the total biomass production potential on the entire marginal area is 13,521.7×10 4 t yr −1 ; the bio-electricity generation and total greenhouse gas saving potential from these biomasses are 183.9 TW h yr −1 and 21,242.4×10 4 t CO 2 eq. yr −1 , respectively. The spatial distribution of the suitable marginal areas shows that they are mainly concentrated in the central part of Northeast China and the Loess Plateau. Both regions are recommended as priority development zones for the Chinese miscanthus-based bioenergy industry. [ABSTRACT FROM AUTHOR]

Miscanthus lutarioriparius is an endemic species in China and has been widely accepted as a promising eco-bioindustrial plant. Currently, predominantly used germplasms have narrow genetic diversity, which causes a gene resource utilization plateau. Therefore, this study was designed to map the geographic and genetic distribution of M. lutarioriparius. Grid search tuning technique was applied to combine occurrence sites, which was followed by the genetic diversity analysis using the Simple Sequence Repeat markers. The results have revealed that the natural distribution of M. lutarioriparius is in the area with altitude less than 300 m and enclosed by the eastern line of East China Sea, western boundary along the longitude line of 111° E, northern boundary of the Qinling-Huai River line, and the southern line of the 27–28° N in Hunan and Jiangxi, and the 30° N line in Zhejiang. The further analysis has demonstrated that the northern line is mainly determined by the climatic factors, whereas the other three boundaries by the dispersal barriers of the sea and high mountains. The genetic diversity of M. lutarioriparius across its distribution range is high with a total Nei's genetic diversity of 0.2462. Populations from the downstream of the Yangtze River generally have a higher genetic diversity than the relative upstream areas. The centeres of genetic diversity for the M. lutarioriparius across China are located in the central and the southern Jiangsu. Outcomes of this study will help expanding the M. lutarioriparius cultivation through improving breeding and subsequently accelerate the development of biobased industry. • Exact distribution range of M. lutarioriparius across China was firstly mapped. • Spatial distribution of M. lutarioriparius genetic variation was mapped. • M. lutarioriparius has a high genetic diversity than that of other monocots. • Key for the development of future biobased industry. • Central and southern Jiangsu are centers of M. lutarioriparius genetic variation. [ABSTRACT FROM AUTHOR]

Miscanthus has been used to breed a variety of energy crops suitable for cultivation in various adverse environments. The collection, conservation, characterization and maintenance of Miscanthus genetic resources are the basic premises for improving Miscanthus crop varieties and their utilization. Large datasets will be generated at the same time. A system designed to manage and analyse those large datasets of Miscanthus germplasms in a coherent and systematic manner is urgently needed. In the present study, the Miscanthus Germplasm Database (MGDB) is constructed to rationalize the storage, update, query and analysis of Miscanthus germplasm data for a multiuser environment. A multi-criteria decision-making model has been introduced into the MGDB to help evaluate Miscanthus and screen elite germplasm. Four hundred eighty-five representative materials of Miscanthus were evaluated and the results are described below. 1. Assessment of the energy potential: Miscanthus lutarioriparius (particularly accession A0118) and Miscanthus floridulus (particularly accession C0540) are the best species to use for combustion for power generation (CPG)/pyrolysis for bio-oil production (PBP) and fermentation for ethanol production (FEP)/fermentation for biogas production (FBP), respectively. 2. Assessment of the breeding potential: The optimal crossing combination is M. lutarioriparius and M. floridulus because of the parental advantages and complementarity. The C0602/C0540 accessions (M. floridulus) represent a suitable parent together with A0118 to breed new varieties for CPG and PBP; A0118 represents as an alternative parent for breeding to improve C0540 for use in FEP and FBP. 3. Prediction of the species distribution: The elite germplasm resources of M. floridulus are mainly distributed in ten floristic regions: IIID9a, IIID9b, IIID9c, IIID9d, IIID10c, IIID11a, IIID11b, IIID11c, IIID11d and IIID12a. The elite germplasm resources of M. lutarioriparius are mainly distributed in four floristic regions: IIID9a, IIID9b, IIID9d and IIID10c. • A Miscanthus Germplasm Database is constructed to rationalize the storage, update, query and analysis of data. • The Miscanthus Germplasm Database can be used to screen elite germplasms. • The occurrence rate of elite germplasms in the floristic regions can be predicted using the Miscanthus Germplasm Database. • Parental materials for breeding different varieties can be selected using the Miscanthus Germplasm Database. [ABSTRACT FROM AUTHOR]

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]

Perennial energy crops (PECs) such as Miscanthus spp. and switchgrass (Panicum virgatum L.) may have particular influence on microbial communities and their functions in soil organic carbon (C) utilization and mineralization (Cm). In this study, long‐term effects of PECs on Cm and soil hydrolase activities were examined in bulk and rhizosphere soils of Miscanthus and switchgrass grown on a red soil in South China. Long‐term cultivation (10 years) of PECs led to increases in soil organic C (SOC) and the absolute Cm of bulk and rhizosphere soils. Total Cm was correlated with dissolved organic C and dissolved organic nitrogen (N) in red soils. The specific Cm in bulk soils of switchgrass and Miscanthus were decreased by 11.73% and 20.67% comparing with the control group, respectively. Cultivation of PECs led to a relatively high C/N ratio. There was a difference in priming effect on activities of β‐glucosidase (BG), leucine amin peptidase, N‐acetyl‐β‐glucosaminidase (NAG), and phosphatase between rhizosphere and bulk soils. Compared with the control without PECs, BG activity did not change significantly in bulk soils of PECs, whereas NAG activity decreased significantly. Soil microorganisms were generally limited by soil C and phosphorus (P) in the red soil. The C and P limitations were significantly linearly related with relative Cm (p < 0.05). Phosphorus limitations in microbial communities were lower with PECs than in the control, indicating that cultivation of PECs could provide an optimal nutrient environment for both plants and microorganisms. Thus, long‐term cultivation of PECs increased SOC content but decreased specific Cm rates. However, because C and P limitations remain for plants and soil microbial communities, optimum fertilization is also necessary for sustainable growth of PECs on red soils. [ABSTRACT FROM AUTHOR]

Alternative energy sources, derived from biomass feedstocks, are important for China's energy security. To evaluate China's capacity for bioenergy in the future, Geographic Information System (GIS) techniques were adopted to identify potentially productive marginal areas for the growth of 16 energy crops and to comprehensively estimate their biomass and bioenergy production potential under three scenarios. The results showed that a total of 267.23 Mha (i.e., million hectare) of marginal land was available for energy crop production. When assessing the suitability of individual environments for each type of energy crop, the largest total land area of a lignocellulosic energy crop, an oil energy crop, and a lignocellulosic energy tree were 3.64 Mha (Miscanthus spp.), 45.44 Mha (Jatropha curcas L.), and 63.55 Mha [Haloxylon ammodendron (C. A. Mey.) Bunge], respectively. In addition, the proposed production of bioethanol [Sorghum bicolor (L.) Moench], biodiesel [Swida wilsoniana (Wanger.) Sojak], and bio-electricity [H. ammodendron] in the baseline scenario met 31.83%, 26.08%, and 9.2% of ethanol demand for E10, diesel, and electricity in 2016, respectively. Furthermore, if upland and forest land could be used to produce bioenergy, the bioethanol substitution rates of ethanol for E100, diesel, and electric power were calculated as 62.63%, 153.94%, and 60.47%, respectively, for 2040. The results indicated that China's future energy demands could not be satisfied by simply depending on energy crops in most situations. Future bioenergy should be developed based on reliable supplies of several types of biomass materials and dedicated biochemical or thermochemical conversion processes, among other renewable energy sources. [ABSTRACT FROM AUTHOR]

The sustainability of bioenergy cropping systems hinges on the dynamics of soil organic carbon (SOC). Switchgrass and Miscanthus , as the two leading perennial energy crops, have been extensively cultivated on marginal land for bioenergy production. However, the effects of their cultivation on SOC sequestration and its underlying mechanisms remain unclear. Herein, we quantified the contributions of plant– and microbial–derived C to SOC accumulation by tracing 13C natural abundance and amino sugars on switchgrass- and Miscanthus -planted lands (i.e. belongs to poor acidic red soil) experienced 10 years of C 3 –C 4 vegetation conversion. The results showed Miscanthus cultivation induced an approximately 6.3 times greater improvement in SOC compared to switchgrass. However, the organic C stability in Miscanthus -planted soil was comparatively lower than that of switchgrass. This was consistent with our global meta-analysis, whereby Miscanthus and switchgrass cultivation were observed to increase SOC by 16.0% and 7.1%, respectively. Miscanthus –cultivated soil was more replenished by plant–derived C stored in particulate organic C, owing to the greater biomass and lower root quality (reflected by the high ratio of lignin to nitrogen). In contrast, switchgrass–cultivated soil was enriched with more microbial–derived C, as its greater root quality induced a more efficient C utilization by the microbes. This was preferentially associated with the soil minerals. In conclusion, perennial energy crops cultivation on marginal land substantially enhances SOC sequestration, whereas the stability of SOC is dependent on the root traits. • Switchgrass and Miscanthus cultivation enhance SOC sequestration on marginal land. • Switchgrass cultivation stimulates more microbial-derived C accumulation. • Miscanthus -cultivated soils store more C 4 -derived C. • The SOC accrual contrasting pathway is dependent on root biomass and quality. [ABSTRACT FROM AUTHOR]

Miscanthus is an important plant resource in China, which has energy plant value, bio-material value, and ecological value. However, the taxonomy of Miscanthus remains poorly defined. To clarify the phylogenetic relationships among the Miscanthus species found in China, here we describe their morphological characters, simple sequence repeats (SSRs), inter simple sequence repeats (ISSRs), and trnL-F and rpl16 gene sequences. We identified M. sacchariflorus and M. lutarioriparius as the closest relatives of M. sinensis and M. floridulus , all of which constituted a major group. At the molecular levels, M. lutarioriparius and M. sacchariflorus were always grouped to form a monophyletic group. M. floridulus appeared as a stable secondary clade of M. sinensis. M. nepalensis , M. nudipes , and M. paniculatus were separated from the major group and more closely linked to an outgroup. M. paniculatus fell into an isolated position outside of the major group. Therefore, our findings support placing M. sacchariflorus and M. lutarioriparius in Miscanthus , treating M. lutarioriparius as a variety of M. sacchariflorus , treating M. floridulus as a subspecies of M. sinensis. We do not support merging M. nepalensis and M. nudipes into Miscanthus and propose the recognition of Diandranthus as a standalone genus, which includes D. nepalensis and D. nudipes. We do not support merging M. paniculatus into Miscanthus , and we support the recognition of Rubimons as a separate genus, including R. paniculatus. These data should help with efforts to evaluate and use Miscanthus germplasms. • Phylogenetic relationships between Chinese Miscanthus species and its relatives. • Morphological characters, SSR, ISSR, and trnL-F and rpl16 gene sequences. • Better evaluation and utilization of Miscanthus germplasm resources. • Miscanthus species were distinguished by morphological and molecular indicators. [ABSTRACT FROM AUTHOR]