Variation on biomass yield and morphological traits of energy grasses from the genus Miscanthus during the first years of crop establishment

This study presents the results of investigations of variation, genotype × year interactions and genotype × year × location interactions for the yield and morphological traits of several selected clones of energy grasses of the genus Miscanthus. The analyses were performed on the best clones of selected hybrid plants, which were obtained within the species M. sinensis or are the result of interspecific hybridization of M. sinensis and M. sacchariflorus. Analyses were conducted on the basis of three-year field trials at two locations. The young plants produced from in vitro cultures were planted at a density of one plant per m². The early stages of plant development, from planting until peak yield in the third year of cultivation, were analysed. Statistical analyses performed on the yield and morphological traits as well as changes in these characteristics over the successive years of the study showed considerable genotypic variation for traits under study. Moreover, significant genotype × year interactions as well as genotype × year × location interactions were observed in terms of yield and morphological traits. Based on the collective results of the study, we suggest that apart from M. x giganteus particularly hybrids of M. sinensis × M. sacchariflorus, should be taken into consideration in genetic and breeding studies on the improvement of yield from energy grasses of the genus Miscanthus.     

Key traits for biomass production identified in different Miscanthus species at two harvest dates

To grow the bioenergy crop Miscanthus x giganteus on wider climate range requires enlarged genetic variability. Our objective was to identify key traits favouring the production of above-ground yield in a cropping environment of Miscanthus at two harvest dates. Canopy height, panicle height, shoot number, stem diameter and above-ground yield of twenty-one clones were studied and compared with emergence earliness and growth traits at autumn and winter harvests in Northern France, during the second and third crop years.Crop age, clone, harvest date, and corresponding double interactions were significant for all traits. Species and ploidy explained clone sum of square effects (92%, 78%, 80% and 89% for canopy height, panicle height, shoot diameter and yield, respectively) and clone × age and clone × harvest date interactions for yield (94% and 77%, respectively). Plant height and shoot number were higher in the third year than in the second, whatever the harvest date. The above-ground development between the two years was higher in winter harvest than in autumn, mostly for M. sinensis. Higher above-ground development and yields were observed for M. x giganteus and M. floridulus than M. sinensis and M. sacchariflorus as well as for triploid and tetraploid M. sinensis and M. sacchariflorus than diploids. Plant height, stem diameter, lateness at panicle emergence or flowering and growth rate were the main traits positively related to yield, in contrast to shoots number and growth duration. This would help to early identify high-yielding clones and breed new inter-specific hybrids.     

Steam gasification of energy crops of high cultivation potential in Poland to hydrogen-rich gas

In the paper energy crops of considerable cultivation potential in Poland, namely: Salix viminalis, Helianthus tuberosus, Sida hermaphrodita, Spartina pectinata, Andropogon gerardi and Miscanthus X giganteus were tested in terms of steam gasification reactivity of biomass chars, as well as yields and composition of product gas in steam gasification and lime-enhanced steam gasification in a laboratory scale fixed bed reactor at 650 °, 700 ° and 800 °C.The highest value of reactivity for 50% of carbon conversion, R₅₀, was observed for Sida hermaphrodita, regardless the process temperature.Application of CaO for in-situ CO₂ capture in steam gasification of biomass chars resulted in hydrogen content increase at 650 °C to the levels comparable with the ones reached at 800 °C without carbonation reaction. Also hydrogen and total gas yields increased in tests of lime-enhanced gasification.     

Slow expansion and low yields of willow short rotation coppice in Sweden; implications for future strategies

About 16 000 ha of commercial willow Short Rotation Coppice (SRC) fields for production of biomass for energy were planted in the early 1990s in Sweden. The cultivated with SRC area has remained almost stable and was slightly decreased during the last years despite the incentives and predictions for drastic increases. Similar incentives and predictions in other countries have been lately launched. The bioenergy produced in the planted SRC areas in Sweden has been lower than anticipated, partly due to the lower than expected biomass yields and the termination of some willow SRC plantations. Explanations for the low yields are depicted based on analyzing the results of a survey where 175 willow SRC growers participated. Lower biomass yields are attributed to: (i) the low input in management activities; (ii) the choice of land for the willow SRC plantation; (iii) and the level of personal involvement of the farmer. Understanding the reasons to earlier years’ performance of willow SRC is important for development of better performing systems in the future, in Sweden as well as in other countries.     

Consequential life cycle assessment of the environmental impacts of an increased rapemethylester (RME) production in Switzerland

Arable land is a constrained production factor - particular in Switzerland. Merely 45% of the consumed crops are produced domestically. Hence, the additional cultivation of rape for producing methyl ester is assumed to substitute crops used for food production. Consequently, Switzerland has to face the decision either to use the arable land for food production and import fuels or to produce fuel from rape and import the displaced food. Using Consequential Life Cycle Assessment (CLCA), the environmental consequences have been assessed if rape for energetic utilization substitutes rape used as edible oil or barley used as animal fodder. The study shows, that displacing food production by RME production in Switzerland can reduce total GHG emissions, when GHG-intense soy meal from Brazil is substituted by rape and sunflower meal, which is a co-product of the vegetable oil production. On the other hand, an increased production of vegetable oils increases various other environmental factors, because agricultural production of edible oil is associated with higher environmental impacts than the production and use of fossil fuels. In summary, the environmental impacts of an increased RME production in Switzerland rather depend on the environmental scores of the marginal replacement products on the world market, than on local production factors.     

Investigating the effectiveness of environmental assessment of land use change: A comparative study of the approaches taken to perennial biomass crop planting in São Paulo and England

There is a move towards large-scale planting of perennial bioenergy crops in many countries to help reduce Green House Gas emissions, whilst still meeting energy demand. However, the implications of such wholesale land use change have yet to be fully understood which raises some concerns over the strategy. This paper identifies, through literature review, that significant social, economic and environmental impacts might be expected from land use change in two different parts of the world, São Paulo, Brazil, where sugarcane is the predominant perennial biomass crop, and England where miscanthus and short rotation coppice are likely to predominate. In order to examine the extent to which these impacts can be addressed in decision-making, the paper develops a framework for testing the effectiveness of environmental assessment practice in these two regions, and applies it to both. The conclusion is that, whilst tools which can address sustainability impacts in decision-making exist, the legal framework in England precludes their application for the majority of land use change, and in Brazil there is incomplete consideration of social and economic impacts at the strategic level.     

Study of hydrogen production by three strains of Chlorella isolated from the soil in the Algerian Sahara

In this study, the photosynthetic hydrogen production rates by some strains of green microalgae were investigated. Three strains of Chlorella isolated from arid soil and foggaras's water in the Algerian Sahara were used. Chlorella sorokiniana strain Ce, Chlorella salina strain Mt and Chlorella sp strain Pt6 produced hydrogen gas under sulphur-deprived conditions, but its rate was dependent on strain type and oxygen partial pressure in medium. In C. sorokiniana strain Ce, the maximum value of hydrogen accumulated was 147 ml at 222 h at 2% of O₂ pressure. Compared to C. sorokiniana strain Ce, C. salina strain Mt and Chlorella sp strain Pt6 produced less amount of hydrogen, but they were able to sustain with an O₂ partial pressure of up to 11–15.4%. Our data were compared with hydrogen production by Chlamydomonas reinhardtii. In this communication, the relationship between physiological behaviour, biochemical characteristic (starch and protein) and rates gas production (O₂ and H₂) was also specified.     

Development of an improved method of cultivation to obtain high biomass of the red alga Gelidiella acerosa (Gelidiales, Rhodophyta) in the open sea

This study describes a suspended stone (SS) method developed for in situ propagation of Gelidiella acerosa. The biomass yield potentials with various growth parameters were studied and compared to the floating raft method that was regarded as a superior method for Gelidiella propagation. The biomass of G. acerosa produced by the SS method consistently increased from the first to the fourth harvest (r = 0.940; P < 0.01) and ranged from 528 to 3645 g fresh wt m⁻². For the raft method biomass increased from the first to the third harvest (977-1288 g fresh wt m⁻²) and then decreased in the fourth harvest (953 g fresh wt m⁻²). The DGR values of the SS method increased exponentially (r = 0.865; P < 0.05) from the first to the fourth harvest (1.33-2.62%) and these values significantly differed from those obtained from the raft method in the second to fourth harvest (P < 0.001) but did not significantly differ in the first harvest (P > 0.05). The biomass of an individual plant harvested from the SS method was significantly higher (P < 0.001) than those obtained for the raft method at all four harvests. The frequency distribution of weight of an individual plant in the SS method also constantly increased in successive harvests and 5% of the plantings in the fourth harvest attained a biomass of 200-250 g fresh wt. The in situ propagation of this species through the SS method described in this study could be a viable option for conservation and large-scale farming in the sea.     

Soil organic carbon changes in the cultivation of energy crops: Implications for GHG balances and soil quality for use in LCA

The environmental impact of different land-use systems for energy, up to the farm or forest “gate”, has been quantified with Life Cycle Assessment (LCA). Four representative crops are considered: OilSeed Rape (OSR), Miscanthus, Short-Rotation Coppice (SRC) willow and forest residues. The focus of the LCA is on changes in Soil Organic Carbon (SOC) but energy use, emissions of GreenHouse Gases (GHGs), acidification and eutrophication are also considered. In addition to providing an indicator of soil quality, changes in SOC are shown to have a dominant effect on total GHG emissions. Miscanthus is the best land-use option for GHG emissions and soil quality as it sequesters C at a higher rate than the other crops, but this has to be weighed against other environmental impacts where Miscanthus performs worse, such as acidification and eutrophication. OSR shows the worst performance across all categories. Because forest residues are treated as a by-product, their environmental impacts are small in all categories. The analysis highlights the need for detailed site-specific modelling of SOC changes, and for consequential LCAs of the whole fuel cycle including transport and use.