ALBERT

Description: For the C4 perennial grasses, Miscanthus  ×  giganteus and Panicum virgatum (switchgrass) to be successful for bioenergy production they must maintain high yields over the long term. Previous studies under the less conducive climate for productivity in N.W. Europe found little or no yield decline in M . ×  giganteus in the long term. This study provides the first analysis of whether yield decline occurs in M . ×  giganteus under United States. Midwest conditions in side-by-side trials with P. virgatum over 8–10 years at seven locations across Illinois. The effect of stand age was determined by using a linear regression model that included effects of weather. Miscanthus  ×  giganteus produced yields more than twice that of P. virgatum averaging 23.4 ± 1.2 Mg ha −1  yr −1 and 10.0 ± 0.9 Mg ha −1  yr −1 , respectively, averaged over 8–10 years. Relationships of yield with precipitation and growing degree days were established and used to estimate yields corrected for the stochastic effects of weather. Across all locations and in both species, yield initially increased until it reached a maximum during the fifth growing season and then declined to a stable, but lower level in the eighth. This pattern was more pronounced in M . ×  giganteus . The mean yields observed over this longer term period of 8–10 years were lower than the yields of the first 5 years. However, this decline was proportionately greater in M . ×  giganteus than in P. virgatum, suggesting a stronger effect of stand age on M . ×  giganteus . Based on the average yield over the period of this study, meeting the United States Renewable Fuel Standard mandate of 60 billion liters of cellulosic ethanol by 2022, would require 6.8 Mha of M . ×  giganteus or 15.8 Mha of P. virgatum . These appear manageable numbers for the United States, given the 16.0 Mha in the farmland Conservation Reserve Program in addition to another 13.0 Mha abandoned from agriculture in the last decade.

Description: s The goal of this study was to investigate if chilling tolerance of C 4 photosynthesis in Miscanthus can be transferred to sugarcane by hybridization. Net leaf CO 2 uptake ( A sat ) and the maximum operating efficiency of photosystem II ( Ф PSII ) were measured in warm conditions (25 °C/20 °C), and then during and following a chilling treatment of 10 °C/5 °C for 11 d in controlled environment chambers. Two out of three hybrids (miscanes), ‘US 84-1058’ and ‘US 87-1019’, did not differ significantly from the chilling-tolerant M . × giganteus ‘Illinois’ (Mxg), for A sat , and Φ PSII measured during chilling. For Mxg grown at 10 °C/5 °C for 11 days, A sat was 4.4 μmol m -2 s -1 , while for miscane ‘US 84-1058’ and ‘US 87-1019’, A sat was 5.7 and 3.5 μmol m -2 s -1 , respectively. Miscanes ‘US 84-1058’ and ‘US 87-1019’ and Mxg had significantly higher rates of A sat during chilling than three tested sugarcanes. A third miscane showed lower rates than Mxg during chilling, but recovered to higher rates than sugarcane upon return to warm conditions. Chilling tolerance of ‘US 84-1058’ was further confirmed under autumn field conditions in southern Illinois. The selected chilling tolerant miscanes have particular value for biomass feedstock and biofuel production and at the same time they can be a starting point for extending sugarcane's range to colder climates. This article is protected by copyright. All rights reserved.

Description: C 4 perennial grasses are being considered as environmentally and economically sustainable high yielding bioenergy feedstocks. Temporal and spatial variation in yield across the conterminious United States is uncertain due to the limited number of field trials. Here, we use a semi-mechanistic dynamic crop growth and production model to explore the potential of Miscanthus  ×  giganteus (Greef et. Deu.) and Panicum virgatum L. across the conterminous United States. By running the model for 32 years (1979–2010), we were able to estimate dry biomass production and stability. The maximum rainfed simulated end-of-growth-season harvestable biomass for M . ×  giganteus was ca. 40 Mg ha −1 and ca. 20 Mg ha −1 for P. virgatum . In addition, regions of the southeastern United States were identified as promising due to their high potential production and stability and their relative advantage when compared with county-level maize biomass production. Regional and temporal variation was most strongly influenced by precipitation and soil water holding capacity. Miscanthus  ×  giganteus was on average 2.2 times more productive than P. virgatum for locations where yields were ≥10 Mg ha −1 . The predictive ability of the model for P. virgatum was tested with 30 previously published studies covering the eastern half of the United States and resulted in an index of agreement of 0.71 and a mean bias of only −0.62 Mg ha −1 showing that, on average, the model tended to only slightly overestimate productivity. This study provides with potential production and variability which can be used for regional assessment of the suitability of dedicated bioenergy crops.

Description: The first replicated productivity trials of the C4 perennial grass Miscanthus  ×  giganteus in the United States showed this emerging ligno-cellulosic bioenergy feedstock to provide remarkably high annual yields. This covered the 5 years after planting, leaving it uncertain if this high productivity could be maintained in the absence of N fertilization. An expected, but until now unsubstantiated, benefit of both species was investment in roots and perennating rhizomes. This study examines for years 5–7 yields, biomass, C and N in shoots, roots, and rhizomes. The mean peak shoot biomass for M . ×  giganteus in years 5–7 was 46.5 t ha −1 in October, declining to 38.1 t ha −1 on completion of senescence and at harvest in December, and 20.7 t ha −1 declining to 11.3 t ha −1 for Panicum virgatum . There was no evidence of decline in annual yield with age. Mean rhizome biomass was significantly higher in M . ×  giganteus at 21.5 t ha −1 compared to 7.2 t ha −1 for P. virgatum , whereas root biomass was similar at 5.6–5.9 t ha −1 . M . ×  giganteus shoots contained 339 kg ha −1  N in August, declining to 193 kg ha −1 in December, compared to 168 and 58 kg ha −1 for P. virgatum . The results suggest substantial remobilization of N to roots and rhizomes, yet still a substantial loss with December harvests. The shoot and rhizome biomass increase of 33.6 t ha −1 during the 2-month period between June and August for M . ×  giganteus corresponds to a solar energy conversion of 4.4% of solar energy into biomass, one of the highest recorded and confirming the remarkable productivity potential of this plant.

Description: To achieve the goals of energy security and climate change mitigation in Denmark and the EU an expansion of national production of bioenergy crops is needed. Temporal and spatial variation of yields of willow and Miscanthus are not known for Denmark because of a limited number of field trial data. The semi-mechanistic crop model BioCro was used to simulate the production of both short rotation coppice (SRC) willow and Miscanthus across Denmark. Predictions were made from high spatial resolution soil data and weather records across this area for 1990-2010. The potential average, rain-fed mean yield was 12.1 Mg DM ha −1 yr −1 for willow and 10.2 Mg DM ha −1 yr −1 for Miscanthus. Coefficent of variation as a measure for yield stability was poorest on the sandy soils of northern and western Jutland and the year-to-year variation in yield was greatest on these soils. Willow was predicted to outyield Miscanthus on poor, sandy soils whereas Miscanthus was higher yielding on clay-rich soils. The major driver of yield in both crops was variation in soil moisture, with radiation and precipitation exerting less influence. This is the first time these two major feedstocks for northern Europe have been compared within a single modeling framework and providing an important new tool for decision making in selection of feedstocks for emerging bioenergy systems. This article is protected by copyright. All rights reserved.

Description: This study characterized phenotypic and genetic variation of overwintering ability in a Miscanthus sinensis germplasm panel consisting of 564 accessions, evaluated in field trials at three locations in North America and two in Asia. Genome‐wide association (GWA) and genomic prediction analyses were performed. The Korea/N China M. sinensis genetic group is a valuable gene pool for cold tolerance. The Yangtze‐Qinling, Southern Japan, and Northern Japan genetic groups were also potential sources of cold tolerance. A total of 73 marker–trait associations were detected for overwintering ability. Estimated breeding value for overwintering ability based on these 73 markers could explain 55% of the variation for first winter overwintering ability among M. sinensis. Average genomic prediction ability for overwintering ability across 50 fivefold cross‐validations was high (~0.73) after accounting for population structure. Miscanthus accessions collected from high latitude locations with cold winters had higher rates of overwintering, and more alleles for overwintering, than accessions collected from southern locations with mild winters. Abstract Overwintering ability is an important selection criterion for Miscanthus breeding in temperate regions. Insufficient overwintering ability of the currently leading Miscanthus biomass cultivar, M. ×giganteus (M×g) ‘1993–1780', in regions where average annual minimum temperatures are −26.1°C (USDA hardiness zone 5) or lower poses a pressing need to develop new cultivars with superior cold tolerance. To facilitate breeding of Miscanthus, this study characterized phenotypic and genetic variation of overwintering ability in an M. sinensis germplasm panel consisting of 564 accessions, evaluated in field trials at three locations in North America and two in Asia. Genome‐wide association (GWA) and genomic prediction analyses were performed. The Korea/N China M. sinensis genetic group is a valuable gene pool for cold tolerance. The Yangtze‐Qinling, Southern Japan, and Northern Japan genetic groups were also potential sources of cold tolerance. A total of 73 marker–trait associations were detected for overwintering ability. Estimated breeding value for overwintering ability based on these 73 markers could explain 55% of the variation for first winter overwintering ability among M. sinensis. Average genomic prediction ability for overwintering ability across 50 fivefold cross‐validations was high (~0.73) after accounting for population structure. Common genomic regions for overwintering ability were detected by GWA analyses and a previous parallel QTL mapping study using three interconnected biparental F1 populations. One QTL on Miscanthus LG 8 encompassed five GWA hits and a known cold‐responsive gene, COR47. The other overwintering ability QTL on Miscanthus LG 11 contained two GWA hits and three known cold stress‐related genes, carboxylesterase 13 (CEX13), WRKY2 transcription factor, and cold shock domain (CSDP1). Miscanthus accessions collected from high latitude locations with cold winters had higher rates of overwintering, and more alleles for overwintering, than accessions collected from southern locations with mild winters.

Description: C 4 perennial grasses are being considered as environmentally and economically sustainable high yielding bioenergy feedstocks. Temporal and spatial variation in yield across the conterminious United States is uncertain due to the limited number of field trials. Here, we use a semi-mechanistic dynamic crop growth and production model to explore the potential of Miscanthus  ×  giganteus (Greef et. Deu.) and Panicum virgatum L. across the conterminous United States. By running the model for 32 years (1979–2010), we were able to estimate dry biomass production and stability. The maximum rainfed simulated end-of-growth-season harvestable biomass for M . ×  giganteus was ca. 40 Mg ha −1 and ca. 20 Mg ha −1 for P. virgatum . In addition, regions of the southeastern United States were identified as promising due to their high potential production and stability and their relative advantage when compared with county-level maize biomass production. Regional and temporal variation was most strongly influenced by precipitation and soil water holding capacity. Miscanthus  ×  giganteus was on average 2.2 times more productive than P. virgatum for locations where yields were ≥10 Mg ha −1 . The predictive ability of the model for P. virgatum was tested with 30 previously published studies covering the eastern half of the United States and resulted in an index of agreement of 0.71 and a mean bias of only −0.62 Mg ha −1 showing that, on average, the model tended to only slightly overestimate productivity. This study provides with potential production and variability which can be used for regional assessment of the suitability of dedicated bioenergy crops.

Description: The first replicated productivity trials of the C4 perennial grass Miscanthus  ×  giganteus in the United States showed this emerging ligno-cellulosic bioenergy feedstock to provide remarkably high annual yields. This covered the 5 years after planting, leaving it uncertain if this high productivity could be maintained in the absence of N fertilization. An expected, but until now unsubstantiated, benefit of both species was investment in roots and perennating rhizomes. This study examines for years 5–7 yields, biomass, C and N in shoots, roots, and rhizomes. The mean peak shoot biomass for M . ×  giganteus in years 5–7 was 46.5 t ha −1 in October, declining to 38.1 t ha −1 on completion of senescence and at harvest in December, and 20.7 t ha −1 declining to 11.3 t ha −1 for Panicum virgatum . There was no evidence of decline in annual yield with age. Mean rhizome biomass was significantly higher in M . ×  giganteus at 21.5 t ha −1 compared to 7.2 t ha −1 for P. virgatum , whereas root biomass was similar at 5.6–5.9 t ha −1 . M . ×  giganteus shoots contained 339 kg ha −1  N in August, declining to 193 kg ha −1 in December, compared to 168 and 58 kg ha −1 for P. virgatum . The results suggest substantial remobilization of N to roots and rhizomes, yet still a substantial loss with December harvests. The shoot and rhizome biomass increase of 33.6 t ha −1 during the 2-month period between June and August for M . ×  giganteus corresponds to a solar energy conversion of 4.4% of solar energy into biomass, one of the highest recorded and confirming the remarkable productivity potential of this plant.

Description: Replacing fossil fuels with an economically viable green alternative at scale has proved most challenging in the aviation sector. Recently sugarcane, the most productive crop on the planet, has been engineered to accumulate lipids. This opens the way for production of far more industrial vegetable oil per acre than previously possible. This study performs techno-economic feasibility analysis of jet fuel production from this new cost efficient and high yield feedstock. A comprehensive process model for biorefinery producing hydrotreated jet fuel (from lipids) and ethanol (from sugars), with 1 600 000 MT yr −1 lipid-cane processing capacity, was developed in SuperPro Designer. Considering lipid-cane development is continuing for higher oil concentrations, analysis was performed with lipid-cane containing 5%, 10%, 15%, and 20% lipids. Capital investments for the biorefinery ranged from 238.1 to 351.2 million USD, with jet fuel capacities of 12.6–50.5 million liters (correspondingly ethanol production of nil to 102.6 million liters). The production cost of jet fuel for different scenarios was estimated $0.73 to $1.79 per liter ($2.74 to $6.76 per gal) of jet fuel. In all cases, the cost of raw materials accounted for more than 70% of total operational cost. Biorefinery was observed self-sustainable for steam and electricity requirement, because of in-house steam and electricity generation from burning of bagasse. Minimum fuel selling prices with a 10% discount rate for 20% lipid case was estimated $1.40/L ($5.31/gal), which was lower than most of the reported prices of renewable jet fuel produced from other oil crops and algae. Along with lower production costs, lipid-cane could produce as high as 16 times the jet fuel (6307 L ha −1 ) per unit land than that of other oil crops and do so using low-value land unsuited to most other crops, while being highly water and nitrogen use efficient.