The effects of integrated food and bioenergy cropping systems on crop yields, soil health, and biomass quality: The EU and Brazilian experience

Integrated food and bioenergy production is a promising way to ensure regional/national food and energy security, efficient use of soil resources, and enhanced biodiversity, while contributing to the abatement of CO2 emissions. The objective of this study was to assess alternative crop rotation schemes as the basis for integrating and enhancing the sustainable biomass production within the food-energy agricultural context. Sunn hemp (Crotalaria spp.) in rotation with wheat (Triticum spp.) in the EU and with sugarcane (Saccharum spp.) in Brazil were evaluated. Sunn hemp did not negatively affect crop's productivity and soil fertility; wheat grain yields were maintained around the mean regional production levels (6, 7, 3 and Mg ha(-1) in Greece, Italy, and Spain, respectively), and the cumulative biomass in the extended rotation (wheat straw+sunn hemp) was between 1.5 and 2.0 times higher than in the conventional rotation. In Brazil, sugarcane stalks yield in clay soils increased by around 15 Mg ha(-1) year(-1) under sunn hemp rotation in comparison with bare fallow. Moreover, sunn hemp in the EU rotations did not have negative effects on soil available macronutrients, organic matter, pH, and cation exchange capacity, neither on C and N stocks in Brazil. The qualitative characteristics (mineral, ash, and hemicelluloses contents) of the cumulated biomass were somehow higher (in average +26%, +35%, and +3.4%, respectively) than in the conventional system. In summary, in temperate and tropical climates the integration of dedicated biomass legume crops within conventional systems could lead to enhanced biomass availability, crop diversification, and efficient use (in space and time) of the land resources

Long-Term Yields of Switchgrass, Giant Reed, and Miscanthus in the Mediterranean Basin

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 22 years) 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 10.0 Mg 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 13.6 Mg 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 22 years) 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

Long-term studies on switchgrass grown on a marginal area in Greece under different varieties and nitrogen fertilization rates

Switchgrass (Panicum virgatum L.) is a perennial grass that has been selected as a candidate bioenergy crop for USA in the early 80s, while the research in Europe started a decade later. A long-term study on switchgrass had been carried out (1998\ue2\u80\u932015) on a marginal area in Greece comparing five varieties (having lowland or upland ecotype) at increasing nitrogen fertilization rates (0, 75 and 150 kg N ha\ue2\u88\u921). Due to the successful establishment of the plantation quite satisfactory yields were recorded even at the establishment year (8.9 Mg DM ha\ue2\u88\u921) and the ceiling yields were recorded in the 2nd year and came up to 20 Mg DM ha\ue2\u88\u921. The under study lowland varieties (Alamo, Kanlow and Pangburn) were more productive compared to the upland varieties (Blackwell and CIR) with mean dry yields 12.37 and 11.39 Mg ha\ue2\u88\u921, respectively and showed higher resistance to lodging. Among the five under study varieties, Alamo was the best performing giving an average yield of 12.7 Mg DM ha\ue2\u88\u921, averaged over all treatments and years, while CIR was the least performing producing a corresponding average yield of 10.8 Mg DM ha\ue2\u88\u921. From the fourth growing season and onwards significantly higher yields were recorded under increasing N fertilization up to 150 kg N ha\ue2\u88\u921 with an average yield of 13.9 Mg DM ha\ue2\u88\u921 (150 kg N/ha) over all varieties and years. The corresponding yields for the other two tested nitrogen rates (0 and 75 kg N/ha) were 10.31 and 11.69 Mg DM ha\ue2\u88\u921, respectively

Comparative studies on several castor (Ricinus communis L.) hybrids: Growth, yields, seed oil and biomass characterization

For three growing periods (2011, 2012 & 2014) a total number of tencastor hybrids (Kaiima 71, Kaiima 75, Kaiima 93, C854, C855, C856, C 857, C864, C1002 and C1008) were tested in Greece (Aliartos; 2011, 2012 & 2014) and Italy (Cadriano; 2014) in order to compare the seed yields and straw production as well as to evaluate residual straw as solid biofuel. In Greece, the mean seed yields, was 2.77. t/ha and ranged from 1.68. t/ha (C865, 2012) to 4.27. t/ha (Kaiima 93, 2011). Correspondingly, the mean oil content of the castor seeds was 48.12% with a range from 45.5% (C1008, 2014) to 52.1% (Kaiima 75, 2011). In Italy, the mean seed yields was 2.46. t/ha and varied from 0.94. ton/ha (C855) to 4.44. ton/ha (C856). In both sites the seed yields were significantly affected by the hybrid. In terms of the common tested hybrids (C855, C856, C864 and C1008) it was found that the best performed hybrid in Greece was C855 with seed yields 3.87. t/ha, while in Italy was C856 with 4.44. t/ha. The remaining dry biomassyields varied from 0.88. t/ha (2012) to 2.86. t/ha (2011). The gross calorific value (GCV) of the remaining biomass was 4035. kcal/kg and the net calorific value (NCV) was 3852. kcal/kg. The ash content was quite high, varied from 9.21% (Kaiima 93, 2012) to 11.75% (C864, 2012), while the nitrogen content was quite low, ranged from 0.73% (C855) to 0.94% (Kaiima 93)

Switchgrass

The knowledge that has been collected on switchgrass at world level, covering the whole production chain, is presented in this chapter. Although several breeding programs have been carried out in the United States, switchgrass is still considered primarily as an undomesticated plant with great potential for agronomic and biofuel trait improvements. There are a large number of available varieties (lowland and upland) covering latitudes from Mexico to the far north of North America. When switchgrass had been successfully established the celling yields could be anticipated as early as the second or third year, and its lifespan could be longer than 15years. In most studies, lowland varieties have been reported as more productive than upland varieties. Nitrogen fertilization should be avoided at the establishment year but should be applied from the second year and thereafter on an annual basis. Most studies agreed that the final harvest should be done a few weeks after a killing frost (winter). The harvested biomass is characterized by a high portion of leaf material (∼40%), while its moisture content may be quite low (∼20%). The lignocellulosic biomass of switchgrass is suitable for energy production through thermochemical (gasification, combustion, and pyrolysis) and biochemical (advanced biofuels: bioethanol and biogas) processes

Agronomic performance and seed quality attributes of Camelina (Camelina sativa L. crantz) in multi-environment trials across Europe and Canada

Camelina (Camelina sativa L. Crantz) is considered a relatively new oilseed Brassicacea in both Europe and North America, even though its history as a crop dates back to the Bronze Age. Camelina has recently received renewed interest from both the scientific community and bio-based industries around the world. The main attractive features of this species are: drought and frost tolerance, disease and pest resistance, a unique seed oil composition with high levels of n-3 fatty acids, a considerably high seed oil content, and satisfactory seed yields, in particular under low-input management and in limiting environments. Aiming at evaluating the feasible introduction of recently released camelina breeding lines under different environmental conditions and their productive potential a multi-location trial was set up. The agronomic performance of nine improved genotypes of camelina was evaluated in a wide range of environments in Europe (Greece, Italy, Poland) and in five locations across Canada, in two consecutive growing seasons (2015 and 2016). Sowing time was optimized for each location according to the different climatic conditions. Camelina proved to be a highly adaptable species, reaching seed yields of about 1MgDMha-1 under the most limiting conditions (i.e., low precipitation, poor soil quality, extremely high temperature at flowering). Growing environments characterized by mild temperatures and adequate rainfall (>170mm, during the growing season) resulted in higher average seed yields. The length of the growing cycle varied greatly between different locations (80-110d), but the cumulative thermal time was quite stable (∼1200 GDD, growing degree days). The advanced breeding line 787-08, which possesses up to 30% larger seed compared to the mean seed size of all other test entries, proved to be the most promising genotype across all locations in Europe and Canada, combining high seed yields (1.1-2.7MgDMha-1) with improved yield stability. To the best of our knowledge, for the first time, camelina lines with improved oil composition (i.e., increased oleic and α-linolenic and lower linoleic acid contents) for feed, food and industrial applications were identified (789-02 and 887).</p