Search

The European energy policy promotes a gradual substitution of fossil fuels with renewable sources to reduce greenhouse gas emissions. This is motivated by increasing oil costs, the need to achieve partial energy independence, and reducing greenhouse gas emissions. However, the use of agricultural land to cultivate energy crops has increased the competition between fuel and food. To avoid this problem, the production of energy crops could be carried out in marginal lands that are unproductive due to unfavorable conditions such as for the limitations on nutrients and water availability or for the presence of contaminants as hydrocarbons or heavy metals. For example, in the case of heavy metal contaminated soils, one option could be the use of plants to extract or immobilize contaminants in the soil. This process is called phytoremediation. The possibility to use energy crops coupling a good phytoremediation potential and biomass production for bioenergy purposes highlights the opportunity to enhance these areas reducing the risk of abandonment of these lands due to the soil pollutions. Carthamus tinctoriusL., an oilseed crop belonging to the family Compositae, is an annual herbaceous plant with a deep root system, and the oil extracted from the seeds is an excellent oil for biofuel conversion. In this study, C. tinctorius was tested in soil contaminated with Zinc, Cadmium, Lead and Nickel, to ascertain their effects on yield and the heavy metal content in the different part of the plant.The results highlight that Safflower can tolerate the presence of heavy metals in the soil. Among the heavy metal studied, safflower seems to be more susceptible to the presence of zinc in the soil., Proceedings of the 30th European Biomass Conference and Exhibition, 9-12 May 2022, Online, pp. 183-186

Saccharum spontaneum ssp. aegyptiacum is a perennial rhizomatous grass that has been attracting great attention as a bioenergy crop in the Mediterranean area. In this study, an innovative propagation method by single-node stem cuttings, as alternative to the costly propagation by rhizomes, was applied in S. spontaneum. The effects of five excision times from mother plants and subsequent transplant of stem-cuttings in pots (from October 2020 to June 2021, at 2-month intervals) and four cuttings pre-treatments: no soaking (control), 24-h soaking in water (W), indole-3-acetic acid solution (IAA, 100 ppm), or indole-3-butyric acid solution (IBA, 100 ppm), were assessed upon cuttings shooting and rooting. Rooting in the control was maximized (67%) in October. Soaking in water or in IBA promoted the rate of rooting from February onwards, and the rate of shooting from April onwards. The promoting effects of IAA upon rooting and shooting were more evident in February and April. Shoot growth was greatly affected by the course of air temperature, being rather low in winter, and high in June. All pre-treatments significantly promoted shoot growth over the control, especially in April and June transplants. This study reveals that stem-cuttings may represent a useful and viable alternative to costly method by rhizomes, in the agamic propagation of S. spontaneum., Proceedings of the 30th European Biomass Conference and Exhibition, 9-12 May 2022, Online, pp. 133-136

Low-ILUC risk feedstock requires genotype selection with climate change and abiotic stress resilient traits to cope unsuitable sites for food crops. Giant reed is a C3 warm-season perennial energy grass that has received great attention for drought prone areas of southern Europe. Although phenotypic variability exists in giant reed, the restricted genetic diversity, inability to produce viable seeds and highly polyploidy of this species basically precludes breeding effort. This study compared 12 giant reed clones obtained at the University of Bologna (Italy) from mutagenesis .-irradiation of in vitro cell cultures. Preliminary observations at the University of Bologna identified a subset of 12 mutant clones with positive alterations in shoot morphology and architecture (increased plant height, higher number of stems per plots, erect habitus) when compared with giant reed wild type. To this end, twelve mutant clones were selected and compared side-by-side in fiend, in a semiarid environment in southern Italy (University of Catania, Italy) for yield and morphology. First year results of biomass yield and morphology under non-limiting water conditions are reported here, and compared with a local clone of giant reed grown in a complementary field experiment aside., Proceedings of the 30th European Biomass Conference and Exhibition, 9-12 May 2022, Online, pp. 125-128

Bioenergy perennial grasses (BPGs) are efficient from a water perspective and can afford a low-energy cultivation system. This work reports the results of the first-year harvest that screened several genotypes of three species (Miscanthus hybrids, Arundo donax and Saccharum spontaneum spp. aegyptiacum) under two irrigation levels at the establishment year. The results highlighted the effect of irrigation water at establishment to improve biomass yield. However, significant differences were observed between species and ecotypes/hybrids: S. spontaneum showed the highest reduction in biomass yield when irrigation water was reduced, while A. donax and the two new seed-based hybrids showed similar biomass yield at both irrigation levels. The leaf to mass ratio was highest in GNT3 and GNT43; this is an interesting trait for advanced biochemical conversions. This is the first time these new Miscanthus hydrid (GNT3 and GNT43) are grown in Sicily and compared with well-known perennial grasses, including M. x giganteus The results refer to the biomass production of stands during the first year after plant establishment. Species have not yet reached the optimal age for biomass productivity, hence, the potential of these genotypes will be evaluated in the next growing seasons., Proceedings of the 30th European Biomass Conference and Exhibition, 9-12 May 2022, Online, pp. 129-132

Castor (Ricinus communis L.) is a member of the Euphorbiaceae family that is found across all the tropical and semi-tropical regions of the world. It is an important oilseed crop and its inedible oil is widely used in industrial, pharmaceutical and agricultural sectors. Castor plants show a high potential to be converted and use as a biorefining feedstock. Castor oil can be utilised for biodiesel production, while the main by-products generated in the castor oil production (capsule shells and castor oil cake) and the residual biomass, are potentially applicable as feedstocks for advanced ethanol and biomethane production. The production of biomethane through anaerobic digestion using agricultural waste has been widely adopted as innovative, sustainable and cost-effective technology. Similarly to others lignocellulosic materials, in order to use these biomass residues in bioenergy production process it is necessary a pretreatment to expose their compact structure to enzymatic hydrolysis. The aim of this work was to evaluate the effects, on the theoretical biomethane potential, of biological pretreatment using two white-rot fungi (Pleurotus ostreatus and Irpex lacteus) of capsule shells of castor fruits obtained from a trial with two different nitrogen fertilization treatments (0 and 120 kg ha-1). Compared to untreated treatment the fungal pretreatment using P. ostreatus showed an increase of theoretical BMP from castor shells in the biomass harvested in the nitrogen fertilized treatment, (+5%). By contrary, Irpex lacteus pretreatment reported a theoretical BMP similar to that of untreated biomass., Proceedings of the 30th European Biomass Conference and Exhibition, 9-12 May 2022, Online, pp. 769-772

Belonging to the Euphorbiaceae family, Castor bean (Ricinus communis L.) is one of the most important non-edible industrial oilseed crop due to its high oil content which ranges from 40 to 55%. According to its temperature requirements, Castor is expected to be one of the possible oilseed crop to develop and study in the Mediterranean area in order to enhance the cultivation in degraded and marginal land. Field experiment were conducted at the experimental farm of the University of Catania between the period of April and November 2021. The aim was to study the behavior of four dwarf hybrids in comparison with a local variety of castor bean evaluating which sowing date was the best to cultivate castor for avoiding the low-winter temperature and verify the best period of cultivation. The flowering of the first three sowing dates were recorded around the end of July due to temperature and photoperiodic effect. The seed yield was higher for the dwarf hybrids, while the local variety had higher production for the primary racemes because of the shifting of the sowing dates which reduces the growing season., Proceedings of the 30th European Biomass Conference and Exhibition, 9-12 May 2022, Online, pp. 116-119

Reducing agronomic input supply can significantly contribute to decrease the environmental impact of bioenergy cropping systems. Currently, there is a renewed industrial interest in non-food oil crops for different end-uses application. Among species from Brassica genus, Brassica carinata A. Braun is an interesting winter annual crop in warm and semi-arid environments and may provide a rotation alternative with cereal crops, sourcing non-edible oil for the industry, additional incomes to the farmers and soil benefits. The present study compared four Brassica carinata lines (GID-6165, GIP-6164, GID-6091, GID-6084) under two different organic fertilization levels (80 and 160 kg N ha-1) in a semiarid Mediterranean area. These four lines have not been tested in Southern Italy previously, nor under the present low-input cultivation practices in semiarid Mediterranean area. Main findings showed a significant fertilization effect (P=0.05), with the high-input providing higher seed yields and harvest index than low-input. There was no genotype effect, however, the gap between potential (i.e. seed yield at the programmed plant density) and actual yields was rather high for GID-6165 and GID-6080. On the other hand, genotype had the largest effect on the thousand seed weight and the residual biomass yield. In general, GID-6091 and GID-6165 reached seed physiological maturity earlier than GID-6084 and GID-6164 lines. The present study proved that improved B. carinata lines can be grown in semiarid Mediterranean area under low-input organic systems, providing satisfactory seed yields. However, seedbed preparation was noticed to be key to narrow the gap between potential and actual seed yield, particularly under the present clay soil., Proceedings of the 30th European Biomass Conference and Exhibition, 9-12 May 2022, Online, pp. 120-124

Soils give rise to many environmental problems, such as heavy metals pollutant that reduces water resources, leading to serious health problems for humans directly or indirectly, by the contamination of the food crops. Moreover, the cultivation of industrial crops in heavy metals contaminated land improves several ecosystem services, such as biodiversity maintenance and nutrient and water cycling, while promoting soil decontamination through a phytoremediation technique. This biological technique uses plants to remediate the contaminated land while generating economic value in land that used to be unproductivity. However, industrial crop selection is crucial for good results of phytoremediation. In this way, hemp appears suitable for heavy metals contaminated soil. It is possible to obtain high-quality cellulose (stems), oil, and hemp proteins when using different varieties. Still, it requires special attention for several physiological features, crop management, and site-specific selection of genotypes. This work aimed to evaluate the tolerance of two genotypes of industrial hemp (Futura 75 and Kc Dora) in soils contaminated by three heavy metals (Ni, Cd, Pb). The results confirm the possibility to use hemp as possible crops for phytoremediation. Moreover the difference observed among the two studied genotypes suggest the possibility to investigate others genotypes., Proceedings of the 30th European Biomass Conference and Exhibition, 9-12 May 2022, Online, pp. 178-182

Kenaf (Hibiscus cannabinus L.) is a warm-season annual plant grown in the past for the bast fiber. In the last decades, this crop has been re-evaluated for many alternative industrial uses of its biomass (i.e., production of biofuel, biocomposite materials, bioproducts). In this paper, the interaction effects of sowing time (May and June) and plant population (P20 and P40, 20 and 40 plants m-2, respectively) on yield and some biomass parameters were analysed in two cultivars of kenaf (Tainung 2-TAI, and Everglades 41-EVER), in a two-year experiment in semi-arid environment, under irrigation. The aim of this paper was to assess the potential of this crop as an energy or industrial feedstock, in south Mediterranean environment where was never cultivated. Overall, plants from late sowing (June) were smaller and with less node, those at high plant density (P40) were thinner. In both seasons, plants of TAI were taller than those of EVER. Plant weight was greater in P20, and an overall significant negative correlation was found between plant weight and actual plant density (r = -0.76 **). The shift of sowing time reduced significantly the final dry biomass. Crop productivity did not change with plant density, however a higher percent bark corresponded to P40 in both years, cultivars, and sowing times, A simple model was developed to simulate and predict the course of LAI and dry biomass (AGB) with time, using field dataset of 2004, for calibration, and dataset of 2005, for validation. The minor response of LAI to plant population in 2005 led to a low accuracy of model approximation. This result suggests that other variables that are not considered in the model, may influence LAI. Nevertheless, the overall AGB model approximation of observed value was accurate. Concluding, the results revealed that biomass productivity is more influenced by sowing time than by plant density. However, plant population has been found to regulate the proportion of bark/core layers, with important implications for industrial (energy and pulp production) purposes. Further improvements on the simple model developed, e.g., including soil water nitrogen balances submodels, may be done, in order to explore the possibility of using the model under different conditions of soil water content and nitrogen fertilization.

The Mediterranean climate is a climate change hot spot suffering by increasing drought periods during summer, with low rainfall and high evapotranspiration, which are limiting conditions for plant CO2 assimilation and biomass production, particularly for spring-summer crops. This would be even worst under marginal lands, where climatic, terrain and other limiting factors will further aggravate growing conditions and productivity. The present field experiment investigated the response to irrigation of several lignocellulosic perennial grasses. Plant stem density, stem height, stem weight and leaf area index were evaluated during the growing season with a monthly frequency. Stem density showed the lowest values for A. donax genotypes and the highest for the Miscanthus seed-based hybrids. High stem densities are observed at high irrigation levels. Stem height and weight are inversely correlated to stem density. A. donax genotypes had higher stem height and weight than the other genotypes. Irrigation has a significant positive effect on both measures. Leaf area index varied among genotypes, and irrigation increased this trait., Proceedings of the 29th European Biomass Conference and Exhibition, 26-29 April 2021, Online, pp. 345-351

Increasing energy demand and fossil fuel prices together with environmental concerns have motivated scientists to find alternative energy sources such as biofuels. Biofuels are renewable and biodegradable sources of energy with beneficial environmental impacts. Biodiesel is a mixture of mono alkyl esters of vegetable oils or animal fats. Currently, more than 95% of the world biodiesel is produced from edible vegetable oils through different transesterification systems. Castor oil is an excellent raw material in terms of price and quality, but especially this non-edible vegetable oil does not have any issues or compromise food security. Recently, the use of castor oil has attracted attention for producing and optimizing biodiesel production, due to its high content and the possibility to esterify with only methanol, which assures low production costs. Additionally, the use of feedstocks as vegetable oils can contribute to decreasing greenhouses gases such as carbon dioxide, because these oils are obtained from crops which have previously captured this gas during their photosynthetic process. The innovative aspect of this study is the evaluation of the morphologic and productive response of castor bean to changing soil water and nitrogen fertilization under the semiarid Mediterranean climate., Proceedings of the 29th European Biomass Conference and Exhibition, 26-29 April 2021, Online, pp. 85-88

There are several environmental advantages in the use of perennial crops such as reduction of soil erosion, increased soil organic matter, low fertilizer and agrochemical demands and increased biodiversity. Bioproducts, biofuels and bioenergy appears as an alternative to replace petroleum based products and nowadays, using land to grow crops for bioenergy has become an increasingly important policy objective designed in the RED II (2018/2001/EU). In this context, marginal lands appear as an alternative for industrial crops production without threatening food production. Marginal lands can be understood as generally as unproductivity lands which are exposed to stress conditions such as limitations of nutrients or water, or contamination by hydrocarbons or heavy metals. Therefore, production of biomass in marginal soils is being recommended to lessen land use change ethical issues linked with competition with food crops. Contaminated soils hinder the cultivation of traditional food crops, while industrial crops can provide several ecosystem services. However, understanding the tolerance and the phytoremediation of each species to a single contaminant helps us to better clean up the polluted areas and it can be useful for organizing protocols aimed at the reclamation of these areas, reducing time and reducing management costs providing a renewable source for energy and bioproducts. The species suitable to heavy metals polluted soils can be divided in two group: exclusion and resistance. The mechanisms of exclusion prevent the accumulation of toxic concentrations in sensitive sites within the cell, and thus preventing negative effects. The mechanisms of resistance generally concern the development of proteins that allow the plant to resist to heavy metals, allowing the accumulation of the same contaminant in the aerial parts of plant. The aim of this work was to study the physiological response of plants tolerant to heavy metals, in particular, focused the attention on two non-food lignocellulosic perennial grasses: giant reed (Arundo donax L.) and African fodder cane (Saccharum spontaneum L. ssp. aegyptiacum), in soils contaminated by four heavy metals (Cd, Pb, Ni, Zn) with the purpose to observe the physiological response and the mechanisms of resistance in the increasing concentrations of the four soil heavy metals., Proceedings of the 29th European Biomass Conference and Exhibition, 26-29 April 2021, Online, pp. 339-344

Castor (Ricinus communis L.) is a member of the Euphorbiaceae family that is found across all the tropical and semi-tropical regions of the world. Castor is considered to be one of the most promising nonedible oil crop, due to its high annual seed production and yield, and adaptability to semiarid climate and adverse growing conditions. Castor plant is an important renewable resource that has a high potential for use as a biorefining feedstock. Castor oil can be used for biodiesel production, while the main by-products generated in the castor oil production (capsule husks and meal) and the residual biomass, are potentially applicable as feedstocks for advanced ethanol and biogas. Field experiments were conducted over the period 2019-2020 at the Experimental farm of the University of Catania to compare 28 genotypes of Castor (Ricinus communis L.) breed from native perennial plants in the Mediterranean basin in terms of seed and oil yield. The total seed yield ranged between 2985 and 1747 kg ha-1. Oil content in castor seeds was on average 42.7 % and 46.1 % for the primary and secondary racemes, respectively. Oil yield reflected the changes in seed yield obtaining on average 1140 kg ha -1., Proceedings of the 29th European Biomass Conference and Exhibition, 26-29 April 2021, Online, pp. 362-365

Raising water and energy productivity in agriculture can contribute to reducing the pressureon the limited freshwater availability and non-renewable energy sources. Bioenergy perennial grassesare ecient from a water perspective and can a ord a low-energy cultivation system; however, cropselection and cultivation practices for minimizing land use change and maximizing resource use eciencies remain a challenging task in view of sustainable bioeconomy development. The presentwork investigated the soil water e ect on a long-term plantation of Saccharum (Saccharum spontaneumssp. aegyptiacum), a bioenergy perennial grass holding great promise for semiarid Mediterraneanareas. The plantation was in its 13th year following establishment and was subjected to three levels ofirrigation for three successive growing seasons. Regression models between crop water use (CWU)and productivity, biomass composition, energy, and water indicators showed di erent predictioncurves. Raising CWU (from 230 to 920 mm) enhanced the dry biomass yield (from 14.8 to 30.1 Mgha-1) and the net energy value (from 257.6 to 511 GJ ha-1). On the same CWU range, unirrigatedcrops improved the energy eciency (from 99.8 to 58.5 GJ ha􀀀1), the energy productivity (from 5.6to 3.4 Mg GJ-1) and the water productivity (from 114.5 to 56.1 MJ m􀀀3) by reducing the waterfootprint (from 8.7 to 17.8 m3 GJ-1). Biomass composition was also superior in unirrigated crops,as the lower heating value, structural polysaccharides, and the acid detergent lignin were higher, while ash and soluble compounds were lower. Present findings demonstrated the good yield levelsand persistence of Saccharum, improving our knowledge of plant responses to changing soil wateravailability to maximize energy and conserve natural resources, paving the way for sustainablebioeconomy development in the Mediterranean area.

Salinity is one of the most important challenge facing the supply of food to the world population in the future. The soil electrical conductivity threshold set by the Joint Research Center (JRC) to define marginal lands due to salinity is 3.2 dS/m in the top soil. The aim of the present study was to evaluate the biomass yield, morphology and physiology of three different perennial energy grasses, namely Arundo donax, Miscanthus x giganteus and Saccharum spontaneum ssp. aegypticum under increasing soil salinity levels (0, 9.0 and 18.0 dS/m) and NPK fertilization differentiation (0, 60 and 120 kg ha-1). The leaf area index (LAI) of investigated species under salinity and fertilization treatments showed an upward trend followed by a decline as the growing seasons progressed. Across treatments, Arundo showed the highest LAI. In Miscanthus this trait was much more affected by salinity levels than Sacchaum. LAI reduced proportionally with increasing salinity and decreasing fertilization levels. The instantaneous water use efficiency (iWUE), which represents the net photosynthesis over the transpiration rate, showed a fluctuating trend around the mean throughout the growing season. It was the highest in the C4 crops, however, across the average of treatments, the C3 Arundo had an iWUE as high as the other crops in comparison. Surprisingly, the higher the salinity levels the higher the iWUE, across species and fertilization. Fertilization, across species and salinity levels, led to a higher iWUE in unfertilized and intermediated than the highest fertilization level. As expected, the biomass weight at harvest showed a significant effect of species, salinity and fertilization. Across the average of salinity and fertilization, Arundo and Saccharum showed the highest yields (21.8 and 19.4 g plant-1), and Miscanthus the lowest (7.2 g plant-1). Across the average of species and fertilization, there was a significantly higher yield on the lowest salinity level (24.9 g plant-1), followed by the intermediate (13.3 g plant-1) and the highest salinity condition (10.1 g plant-1). The highest level of fertilization significantly improved the biomass weight as compared with the control and the medium fertilization level. Increasing the knowledge on energy crops under soils affected by salinity is strategic to reduce land abandonment, recommending bioenergy crops for marginal lands where food crops may face difficulties to be grown, in turn decreasing the food vs fuel competition and the effect of land use changes., Proceedings of the 28th European Biomass Conference and Exhibition, 6-9 July 2020, Virtual, pp. 216-221

According to the RED II (2018/2001/EU), Member States must supply a minimum of 14% of the energy consumed in road and rail transport by 2030, of which the contribution of advanced biofuels and biogas must reach at least 3.5%. Reduce biomass recalcitrance of high-yielding lignocellulosic crops by means of agronomic strategies would significantly contribute to the advanced biofuel production goal. Lignocellulose is the lowest cost raw material on earth, it is a no-food biomass and its use alone or in mix with other biomasses can strongly increase the biomass availability for advanced biomethane production. The present study evaluated the suitability of the lignocellulosic, herbaceous Arundo donax as a biomass feedstock for advanced biomethane production. Harvest time and nitrogen fertilization treatments were adopted to reduce biomass recalcitrance thereby increasing biomethane yield. Biochemical Methane Potential (BMP) was evaluated on batch anaerobic fermenters in mesophilic conditions. The BMP at 30 days of incubation was influenced by the investigated treatments, the incubation time and the interaction of these two factors. The trend showed a lag phase for the first 5 days of testing, due probably to the adaptation of the bacterial flora to the lignocellulosic matrix, followed by an exponential increase up to approximately 18 days; after that a slight increase tending to an asymptotic trend in the final phase (up to day 30) was observed. The highest BMP was reached by the combination of winter harvest (W) and 80 kg N ha-1 (123.4 Nml CH4 g-1 SV), followed by the autumn harvest (A) and 80 kg N ha-1 (118.1 Nml CH4 g-1 SV). The unfertilized treatments showed an opposite BMP, with the autumn higher than winter harvest (106.2 and 100.3 Nml CH4 g-1 SV, respectively). In terms of biomethane yield per unit land area, WN80 showed the highest (1717 ± 203 m3 CH4 ha-1) and WN0 the lowest (859 ± 93 m3 CH4 ha-1). Nitrogen fertilization looks a promising strategy to reduce biomass recalcitrance for bioconversion by anaerobic digestion mainly due to the higher content of neutral detergent soluble and protein; however, it should be proved by an energy, economic and environmental analysis to ascertain an overall sustainability., Proceedings of the 28th European Biomass Conference and Exhibition, 6-9 July 2020, Virtual, pp. 222-227

The Joint Research Center (JRC) has set a series of thresholds to define marginal lands in terms of biophysical constraints. We focus on climate limitation given by the ratio between precipitations and potential evapotranspiration (P/PET). Indeed, the Mediterranean climates are characterized by long drought periods during summer, with low rainfall and high evapotranspiration, what limits plant CO2 assimilation and biomass production, particularly of spring-summer crops. The present study ascertained the potential and actual yield of African fodder cane (Saccharum spontaneum ssp. aegypticum), a perennial, herbaceous, rhizomatous perennial grass, native from North Africa and widespread in South Mediterranean regions. Saccharum was grown under different water regimes (I0 - rainfed, I50 – 50% ETm and I100 – 100% ETm restoration) for six successive growing seasons, namely from the 7th to the 12th. Throughout the experimental period, the dryness index greatly changed among the six growing seasons: three out of the six (2012, 2013 and 2014) were much lower than the threshold of 0.6 set in the JRC report, indicating severe drought seasons, two were quite similar to the threshold value (2015 and 2016), while the 2011, which was the wettest season overall, had a dryness index higher than the threshold. Actual biomass yield was mostly driven by meteorological conditions through the growing seasons. However, even in the driest seasons, Saccharum was able to maintain satisfactory biomass yield and good yield persistence. As compared to the potential yield (I100), the relative yield reduction over the six years was in the range of 31% in the most stress condition (I0), but the energy productivity and the water footprint improved by 62% and 32%, respectively, indicating a higher sustainability of the cropping system when irrigation water was not provided. When the irrigation level was raised to the 50% of the maximum evapotranspiration restoration (ETm), the relative yield, over the six growing seasons, reduced by 16.5%; the energy productivity and the water footprint improved of only 14 and 22%, respectively. This study underlines the importance for strategic selection of crops for a given environmental condition dominated by a specific biophysical constraint and the agronomic practices leading to increase the energy productivity while reducing the pressure on Mediterranean freshwater., Proceedings of the 28th European Biomass Conference and Exhibition, 6-9 July 2020, Virtual, pp. 34-40

Giant reed (Arundo Donax L.) is a perennial, non-food and low-input energy crop representing a promising solution to produce renewable energy at low cost, especially in marginal areas - i.e. low profitable areas which are prone to land abandonment. This research investigates the effect of two levels of irrigation (100% ETm and rainfed) on a 20-year old plantation of 40 genotypes of giant reed (Arundo donax L.) collected around Southern Italy. The experimental methanogenic potential of the biomass was defined trough the BMP test (Biochemical Methane Potential). The trial shows that several genotypes maintain high biomass yield and thus high biomethane potential yield even from old plantations. The variability of biomass yield and biomethane potential yield among genotypes is high. Giant reed genotypes show a positive response to the irrigation, which represent the main limiting factor in Mediterranean environments., Proceedings of the 28th European Biomass Conference and Exhibition, 6-9 July 2020, Virtual, pp. 234-237

Bioeconomy is “the knowledge-based production and utilization of biological resources to provide products, processes and services in all sectors of trade and industry within the framework of a sustainable economic system” (German Bioeconomy Council, 2015). A growing bioeconomy involves the replacement of fossil by biogenic resources (or biomass) derived from plants, animals or microorganisms. According to the National Renewable Energy Action Plans of the European member states, about double the amount of biomass used for energetic purposes in the year 2012 will be required by 2020. In addition, it is expected that more than 80 million tons of bioproducts will be produced in 2020 (Scarlat et al., 2015) and potentially about 150 million tons of fossil-based products and chemicals could be replaced by biobased products. This indicates a substantial demand for additional biomass to fulfill the EU’s bioeconomy goals. In the envisioned "ideal" bioeconomy, biomass production will take ecological, social and health aspects into consideration (Staffas et al., 2013). From the definitions and ambitions of the bioeconomy, it can be concluded that its growth will require a sufficient supply of sustainably produced biomass. According to (Scarlat et al., 2015), the potential risks arising from increased biomass production and supply in Europe are: The move towards a bioeconomy based on natural resources from land and sea would lead to a large increase in the demand for biomass undermining the sustainability of a biobased economy. Additional land use could lead to negative impacts from land-use change, such as biodiversity, soil carbon and soil fertility losses. The need to increase crop productivity could lead to increased use of fertilizers and pesticides with additional problems related to water and soil pollution. Additional pressure on water resources. Increasing competition for resources between food supply and non-food biomass. The MAGIC project has been established with the ambition of helping mitigate these risks.&nbsp

The main objective of the present study was to assess the biomass dry matter yield (DM), the water use efficiency (WUE), the energy content (EC) and the energy return on investment (EROI) at the farm gate of several perennial grasses grown at the experimental farm of the University of Catania, Italy. Field trials of Arundo donax, Miscanthus x giganteus, Saccharum spontaneum spp. aegyptiacum, Sorghum halepense, Oryzopsis miliacea and Cymbopogon hirthus grown under low-input practices in an autumn and a winter harvesting regime were used. From February 2014 to February 2015 (winter harvest regime), and from October 2014 to October 2015 (autumn harvest regime), the dryness index (P/ET) was computed. Main results suggested that Saccharum was the outstanding species. Across species there was no difference in DM between autumn and winter harvests. On the other hand, WUE was higher in autumn than winter harvest, due to the lower dryness index in the autumn (0.32) than in the winter regime (0.53). The EC, although significantly different, was in the range of 1.0 MJ kg-1 between the most (Miscanthus, 15.9 MJ kg-1) and the least (Oryzopsis, 14.9 MJ kg-1) species. All species can be considered sustainable from the energy point of view as the EROI ranged from 120:1 in Saccharum to 20:1 in Cymbopogon., Proceedings of the 27th European Biomass Conference and Exhibition, 27-30 May 2019, Lisbon, Portugal, pp. 226-230

Research is needed to look for plants or lines that can thrive on soils affected by water deficit or other constraints. The present work investigated the potentiality of Saccharum spontaneum L. spp. aegyptiacum (Willd.) Hack., a lignocellulosic, perennial, rhizomatous, no-food crop in semi-arid Mediterranean area. A 3-year field trial was carried out with the aim to evaluate its physiology, biomass yield, water use efficiency, and biomass quality under different soil water availability. During 2011/2012, 2012/2013, and 2013/2014 growing seasons (hereinafter referred as 2011, 2012, and 2013, respectively), three levels of maximum evapotranspiration restitution (ETm) were compared: I 100 (100% ETm restitution), I 50 (50% ETm restitution), and I 0 (rainfed condition). Net photosynthesis, stomatal conductance, and transpiration rate were strictly related to the available soil water content (ASWC), with maximum gas exchange at field capacity. However, gas exchange between plants and atmosphere was also measured when ASWC was close to wilting point. Biomass dry matter (DM) yield and main morpho-biometric traits (e.g., stem height and basal stem diameter) were significantly affected by ASWC. A non-linear model showed that maximum DM yield, 37.86 Mg ha −1 , can be achieved when 1150 mm of water were used by the crop. Water use efficiency (WUE) was always highest in rainfed condition ( I 0 ), however, only in 2013 I 0 was significantly higher than I 50 and I 100 (5.89 g L −1 vs 4.26 and 3.33 g L −1 ). Within the variables employed, a linear model showed that WUE was negatively related to crop water use (CWU). The fiber content was not affected by the irrigation treatments. In the average, hemicellulose, cellulose, and lignin accounted for 23.9 (% w/w), 35.0 (% w/w), and 19.9 (% w/w), respectively. On the other hand, moisture and ash content, bulk density, low heating value, and ash melting point resulted significantly affected by the treatment. Present results suggested that S. spontaneum spp. aegyptiacum possesses a range of agronomically desirable traits of biomass crop: C4 plant, high biomass yield, active assimilation rates during drought–stress periods, able to use water efficiently, and satisfactory biomass quality.

Uncertainty in predictions of long-term yields of perennial grasses makes business plans untenable in the short run. Long-term data across varied environments, including marginal lands, will help in preventing uncertainty while providing farmers and entrepreneurs with sound information to estimate reliable and affordable strategies on what, where, and how long to grow perennial grasses. In the present study, the long-term yields (11 to 22years) of switchgrass (Panicum virgatum L.), miscanthus (Miscanthus × giganteus Greef et Deuter), and giant reed (Arundo donax L.) grown in northern and southern Mediterranean environments are reported. Switchgrass was grown in Greece and northern Italy, giant reed in southern and northern Italy, and miscanthus in southern Italy. Furthermore, lowland and upland switchgrass ecotypes were compared in Greece. Despite similar biomass productions (9.8 and 10.0Mg DM ha−1 for uplands and lowlands, respectively), the upland ecotypes showed a significantly higher yield stability (CV of 24 and 32% for uplands and lowlands, respectively) over a 17-year period. Biomass yield varied considerably across years and locations; giant reed outperformed switchgrass under northern Italy environment (21.2 and 13.6Mg DM ha−1 for giant reed and switchgrass, respectively). Annual yield of switchgrass was 30% higher in the north than south Mediterranean; miscanthus showed intermediate production compared to giant reed and switchgrass (average of 22years) and a CV similar to switchgrass. In summary, these results evidence that multi-location, long-term trials are strongly needed to reduce uncertainties on crop yield variability and provide more accurate data from which optimized socio-economic and environmental predictions can be achieved.

In the present study the effect of temperature, reaction time and dilute oxalic acid (OA) concentration during steam-pretreatment of Miscanthus × gigantueus has been evaluated using the combined severity factor (CS). At the highest CS glucan and lignin content in the water insoluble fraction (WIF) increased, while xylan content decreased. While glucose recovery in the water soluble fraction (WSF) was found at low concentration when mild CS were used (≤5.0 g L−1 at CS ≤ 2.17), xylose and arabinose concentrations were higher at low-mild CS (1.58–2.17) with a concentration peak at CS 2.03 (39.9 and 3.2 g L−1 for xylose and arabinose, respectively). The decrease in pentoses coincided with inhibitory formation in the WSF, namely acetic acid, furfural, HMF and phenolic compounds. Glucan conversion rose from 46.1% at CS 1.54 to 91.2% at CS 2.76. Likewise, maximum ethanol concentration was achieved at CS 2.76, corresponding to 20.2 g L−1 and a volumetric ethanol productivity of 0.28 g L−1 h−1. Negative correlations have been found between xylan vs. glucan conversion and xylan vs. ethanol production, suggesting that decreasing the xylan content in WIF increases both saccharification rate and ethanol concentration (R2 0.91 and R2 0.93, respectively). On the other hand, a positive correlation was found between ethanol production and glucan conversion (R2 0.93). Fermentation of WSF by Scheffersomyces (Pichia) stipitis CBS 6054 at CS 1.54 produced 12.1 g L−1 of ethanol after 96 h incubation with a volumetric ethanol productivity of 0.13 g L−1 h−1.

A general obstacle to the development of perennial grasses is the relatively high cost of propagation and planting. The objective of the present study was to investigate new propagation and planting methods of giant reed (Arundo donax L.), miscanthus (Miscanthus x giganteus Greef et Deuter) and switchgrass (Panicum virgatum L.). Field and open-air pot trials were carried out in four different locations across Europe: hydro-seeding of switchgrass was tested in field trials at the experimental farm of the University of Bologna, Italy; stem propagation and bud activation methods of miscanthus were evaluated in field experiments in Péteri, Hungary; giant reed rhizome and stem propagations were compared in a field trial in Aliartos, Greece; finally, an open-air pot trial was carried out in Catania, Italy, using single-node stem cuttings of giant reed. Hydro-seeding emerged as a feasible and promising technique for switchgrass to ensure prompt seed emergence and weed control during plant establishment. Direct stem plantings of miscanthus were successful, and activated stem-buds were able to sprout in field conditions; however, timely stem transplant was determinant for shoot density and biomass yield. In giant reed, rhizome propagation showed a higher stem density and biomass yield than stem propagation; however, the yield gap was not significant from the second year onwards. Single-node rooting was mainly driven by air temperature. Nodes from basal stems showed higher rooting rates than median and apical ones. Growth regulator pretreatments enhanced rooting rate only at transplanting times under suboptimal air temperatures. In general, these experiments provided insights into propagation strategies aimed at enhancing the establishment phase of perennial grasses.

Side by side biomass productivities, harvesting time (autumn vs. winter) and frequency (annual vs. biennial) of three perennial grasses were compared under northern and southern Mediterranean climates. Miscanthus ( Miscanthus × giganteus Greef et Deu.) was compared to giant reed ( Arundo donax L.) in Catania (37°24′N, 15°03′E), and to switchgrass ( Panicum virgatum L.) in Bologna (44°55'N, 11°45′E). Generally, giant reed produced about 50% higher biomass than miscanthus in Catania. Miscanthus almost halved biomass productivity in the driest year, while giant reed reduced biomass yield by only 30% under the same conditions. In Bologna, miscanthus and switchgrass produced similar amounts of cumulative biomass over 6 years. Switchgrass kept more stable annual yields than miscanthus, which, however, evidenced a higher potential under favorable climate conditions. Autumn harvest significantly reduced biomass productivity and quality (moisture content, ashes, cellulose and hemicellulose), particularly under South Mediterranean climate. In Catania, autumn biomass was 50% (giant reed) to 85% (miscanthus) lower than winter biomass, while in Bologna, autumn cut reduced switchgrass yield by 20%. Biennial harvesting resulted in almost 40% lower cumulative biomass yield than annual cut, after 6 years.