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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

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

Presentation of the OPTIMa Project

optimized cropping systems of perennial grasses in Mediterranean regions are discussed

The Mediterranean climate is characterized by low summer rainfall, high temperature and evapotranspiration, which combine to limit plant CO2 assimilation reducing biomass yield of spring-summer crops. Climate change scenarios predict even lower rainfall and prolonged summers increasing aridity. Therefore, it is important to identify crops that can use available water efficiently and can withstand prolonged periods of water-deficit. The present experiment assessed the biomass yield and quality of two ecotypes of Arundo donax L, one ecotype of Saccharum spontaneum spp. aegyptiacum and three hybrids of Miscanthus, namely the commercial M. × giganteus, and two new clonal hybrids, GNT9 and GNT10, during the first year of establishment with sufficient irrigation to prevent water deficits. The Miscanthus clonal based hybrids GNT9 and GNT10 have been selected for the adaptability to drought conditions among the F1 generation obtained from interspecific Miscanthus cross. Measurements of total aboveground biomass, stem density, stem weight and biomass quality were recorded from one harvest following the first year after establishment to assess the different establishment phase performances between genotypes. S. spontaneum produced the highest dry biomass yield during the first year of the trial due to the combination of high stem density and stem dry weight. A. donax ecotypes had the highest stem weight, but yields were reduced by the low stem density. In contrast, the yield of Miscanthus hybrids was constrained by low stem weight. Miscanthus hybrids had higher cellulose and hemicellulose and lower content of lignin and neutral detergent soluble (NDS) than A. donax and S. spontaneum whose composition was found to be similar., Proceedings of the 28th European Biomass Conference and Exhibition, 6-9 July 2020, Virtual, pp. 228-233