Perennial grasses as lignocellulosic feedstock for second-generation bioethanol production in Mediterranean environment.

In this paper the suitability of three perennial, herbaceous, lignocellulosic grasses ( Arundo donax , Saccharum spontaneous spp. aegyptiacum and Miscanthus x giganteus ) for the production of second-generation bioethanol in semi-arid Mediterranean environment was studied. Crops were established in spring 2002, supplying irrigation and nitrogen fertilization up to 2004/2005 growing season. Subsequently, crops were grown without any agronomic input and harvested annually. Data reported in this paper refers to 2008/2009 and 2009/2010 growing seasons. Aboveground dry matter (DM) yield was higher in Arundo (35.4±2.1 Mg ha –1 in 2009 and 32.2±1.9 Mg ha –1 in 2010 harvest) than in Saccharum (27.3±2.0 and 23.9±1.9 Mg ha –1 , respectively) and Miscanthus (19.6±2.8 and 17.2±1.6 Mg ha –1 , respectively). Structural polysaccharides of the raw material were higher in Miscanthus (63.4% w/w) followed by Saccharum (61.5% w/w) and Arundo (57.6% w/w). The same trend was identified for the cellulose content (41.0%, 36.8% and 34.6%, respectively). The highest values in the total hemicellulose complex were observed in Saccharum (24.7%), followed by Arundo (23.1%) and Miscanthus (22.4%). The composition of structural polysaccharides leads to a higher theoretical ethanol yield (TEY) from one dry ton of Miscanthus feedstock (kg DM Mg –1 ), followed by Saccharum and Arundo . On the other hand, the TEY per unit surface (Mg ha –1 ) was greater in Arundo than in Saccharum and Miscanthus . When compared to other lignocellulosic sources used in the second-generation bioethanol technology, such as agricultural residues, woody species and other herbaceous perennial crops, Arundo , Saccharum and Miscanthus showed a great potential in terms of TEY ha –1 . Given the high levels of biomass yield and composition of structural polysaccharides, the three species might be introduced into the Mediterranean cropping systems to supply lignocellulosic biomass for second-generation industrial plants or bio-refineries

Physiological responses of Arundo donax ecotypes to drought: a common garden study

Genetic analyses have suggested that the clonal reproduction of Arundo donax has resulted in low genetic diversity. However, an earlier common garden phenotyping experiment identified specimens of A. donax with contrasting biomass yields (ecotypes 6 and 20). We utilized the same well-established stands to investigate the photosynthetic and stress physiology of the A. donax ecotypes under irrigated and drought conditions. Ecotype 6 produced the largest yields in both treatments. The A. donax ecotypes exhibited identical high leaf-level rates of photosynthesis (PN) and stomatal conductance (Gs) in the well-watered treatment. Soil drying induced reductions in PN and Gs, decreased use of light energy for photochemistry, impaired function of photosystem II and increased heat dissipation similarly in the two ecotypes. Levels of biologically active free-abscisic acid (ABA) and fixed glycosylated-ABA increased earlier in response to the onset of water deficit in ecotype 6; however, as drought progressed, the ecotypes showed similar increases in both forms of ABA. This may suggest that because of the low genetic variability in A. donax the genes responding to drought might have been activated similarly in the two ecotypes, resulting in identical physiological responses to water deficit. Despite the lack of physiological ecotypic differences that could be associated with yield, A. donax retained a high degree of PN and biomass gain under water deficit stress conditions. This may enable utilization of A. donax as a fast growing biomass crop in rain-fed marginal lands in hot drought prone climates

Future yields assessment of bioenergy crops in relation to climate change and technological development in Europe

Bioenergy crops are expected to play an important role in reducing CO2 emission, in energy supply and in European energy policy. However, a sustainable bioenergy supply must be resilient to climate change and the impacts on agriculture at both global and regional scale. The purpose of this study was to forecast the potential distribution of several bioenergy crops based on agronomic and environmental constrains under current conditions and future scenarios (2020 and 2030) in European Union. Potential biomass yield, according to the category end use product achievable in each environmental zone of Europe at present and in the future available land have been also studied. Future yields were assessed according to two factors: technological development and climate change: the former was based on prospect of DG-Agriculture for conventional crops and expert judgments for bioenergy crops, while the latter based on relevant research papers and literature reviews which used site-specific crop growth models. Yields are expected to increase in northern Europe due to climate change and technological development, while in southerneastern Europe the negative effect of climate change will be mitigated by the technological development. The estimated total biomass production in Europe, on the basis of future yields and surplus land made available for energy crops, may not be sufficient to meet the needs of bioenergy supply as claimed in the European directive 2009/28/EC

Evaluation Of The Methanogenic Potential Of Two Lignocellulosic Crops

Biogas production can be considered an important technology for the sustainable use of agricultural biomass as a renewable energy source even more when the substrates for anaerobic digestion are crop residues, livestock residues or energy crops that don’t compete with food crops for land use. The aims of this study were to evaluate the production of biogas and biomethane from two lignocellulosic crops suitable for the Mediterranean environment (Arundo donax L. and Saccharum spontaneum subsp. aegyptiacum (Willd.) Hack) and the efficiency of a thermal pretreatment to increase the biomethane production. The purpose of the pretreatment is to break the recalcitrant lignin layer, so that the cellulose and hemicellulose present in the biomass are hydrolyzed by microorganisms and converted into simple sugars to achieve greater energy yield

leaf appearance rate and final main stem leaf number as affected by temperature and photoperiod in cereals grown in mediterranean environment

In the present study, a two-year field trial was carried out with the aim to evaluate daylength and air temperature effects on leaf appearance and related rates in two durum wheat (Triticum durum Desf.), two bread wheat (Triticum aestivum L.) and two barley (Hordeum vulgare L.) cultivars, using six different sowing dates (SD). Significant effects of SD on final main stem leaf number (FLN), thermal leaf appearance rate (TLAR), daily leaf appearance rate (DLAR) and phyllochron (PhL) were found. Cultivars resulted inversely correlated to mean air temperature in the interval emergence - fifth leaf full expansion (E-V). Linear response of leaf number over days after sowing was shown for all SD and cultivars, with R2 higher than 0.95. FLN linearly decreased from the first to the last SD for durum wheat, while more variable behaviour was observed in bread wheat. TLAR and DLAR showed a linear increment of the rate from the first to the last SD in durum wheat, while did not for bread wheat and barley. PhL in durum wheat decreased from the first to the last SD. Barley and bread wheat showed the highest values on those SDs which did not reach flowering. The increase of TLAR was affected by photoperiod and photothermal units in durum wheat, while by temperatures only in barley and bread wheat. Present results might find practical application in the improvement of phenology simulation models for durum wheat, bread wheat and barley grown in Mediterranean area in absence of water and nutrient stress

Achieving hybridisation between Miscanthus species:Commercially-scalable methods to manipulate flowering synchronisation and maximise seed yield

Miscanthus is a high-yielding lignocellulosic perennial biomass crop. The low multiplication rate of clonal rhizome propagation is a bottleneck to upscaling plantation areas of feedstock needed to supply and expand the bioeconomy. Novel seeded Miscanthus hybrids are currently being developed to overcome this bottleneck by increasing annual multiplication rates from approximately 10 to over 1000 times. We describe a series of field experiments in southern Italy using agronomic methods to optimise multiplication rates through (i) planting configurations and densities, (ii) ratio of seed parents to pollen parents (iii) supplemental pre-dawn misting to increase humidity during pollination. In these trials the seed-bearing M. sinensis started flowering 2–3 weeks earlier than the M. sacchariflorus pollen parent. Earlier experiments indicated that flowering in M. sacchariflorus was mostly determined by photoperiod while in M. sinensis it was modulated by endogenous signals. Consequently, a second set of experiments were conducted to delay flowering time in M. sinensis: (iv) mid-season stem cut back, (v) oversupply of nitrogen, and (vi) undersupply of water. Across all treatments and years, the multiplication rates varied from 140 to 1300 seeds m². Reducing the proportion of the pollen parent plants (M. sacchariflorus) from 50 % to 25 % did not reduce seed yield per plant. This therefore increases the seed yield per m² and reduces seed production upscaling costs. Flowering time and duration in M. sinensis was significantly impacted by mid-season cutting and water stress, but not by nitrogen supply rates. Mid-season shoot cutting reduced number of flowers per plant (77 %), seed quantity (47 %), seed size (46 %), and resulted in seeds with a low germination rate of 39 %. High M. sinensis planting densities produced higher seed yields in the first year. However, in subsequent years higher density plots were more susceptible to autumn lodging lowering seed production by loss of panicles. Pre-dawn misting to prolong pollen life and stigma receptivity had no significant effects on seed production. This study demonstrates the importance of flowering time synchronization in the open field for commercial seed production. The limited effect of agronomic efforts to reduce the interspecies flowering time gap emphasises the importance of genetic factors in controlling flowering time. The most impactful intervention to change flowering time and improve parental synchronisation was mid-season cutting, while this method reduced seed production when applied to the seed parent it could be ideal for pollen parents.</p

Valorisation of typical products through characterising and promoting actions: morpho-biometric traits, sensory analysis and flavonol content in Cipolla di Giarratana

The performances of 9 accessions of Cipolla di Giarratana landrace were evaluated at 5 different sites located 2 in the area where this landrace is traditionally grown (South-Eastern Sicily, 550 m asl), 2 in the neighbor areas with similar average altitude, and one on the South East coast of Sicily (sea level). Biometric and morphological traits, flavonol content and sensory profile were all considered in the valorisation of a typical product of a marginal area of Sicily. Data on the actual yield and crop management at farm scale were also obtained involving more than half of the growers actually cultivating Cipolla di Giarratana , and measuring yield, plant density, and bulb weight directly on the farms. The Cipolla di Giarratana landrace is characterised by a large and heavy bulb (535 g), strongly flattened at the poles, with the maximum diameter at the central section, and white in colour. Significant differences in bulb weight and diameter were found among accessions and locations, but there were no interactions between them and one accession reported the highest bulb weight value in all of the locations studied. With regards to bulb weight, farm scale data confirm the results we obtained at the experimental locations. Fifty percent of registered yield at farm scale ranged between 86 and 152 t ha –1 with a median of 119 t ha –1 , and measured plant density revealed that 50% of the farmers planted 20-27 plants per square meter. Analysis of the UV-vis and mass spectra showed the presence of 10 different flavonols with Quercetin as the most represented flavonol. The sensory profile of Cipolla di Giarratana onion showed that this landrace is characterised by a high intensity of sweet, typical fresh flavour and texture perception