1,721,278 research outputs found
Switchgrass: a valuable biomass crop for energy
No full textThe demand of renewable energies is growing steadily both from policy and from industry which seeks environmentally friendly feed stocks. The recent policies enacted by the EU, USA and other industrialized countries foresee an increased interest in the cultivation of energy crops; there is clear evidence that switchgrass is one of the most promising biomass crop for energy production and bio-based economy and compounds. Switchgrass: A Valuable Biomass Crop for Energy provides a comprehensive guide to switchgrass in terms of agricultural practices, potential use and markets, and environmental and social benefits. Considering this potential energy source from its biology, breed and crop physiology to its growth and management to the economical, social and environmental impacts, Switchgrass: A Valuable Biomass Crop for Energy brings together chapters from a range of experts in the field, including a foreword from Kenneth P. Vogel, to collect and present the environmental benefits and characteristics of this a crop whit the potential to mitigate the risks of global warming by replacing fossil fuels. Including clear figures and tables to support discussions, Switchgrass: A Valuable Biomass Crop for Energy provides a solid reference for anyone with interest or investment in the development of bioenergy; researchers policy makers and stakeholders will find this a key resource
Sixteen-Year Biomass Yield and Soil Carbon Storage of Giant Reed (Arundo donax L.) Grown Under Variable Nitrogen Fertilization Rates
Full text linkHigh and stable biomass yields for long periods (15–20 years) are indispensable for the successful establishment of a well-developed bioenergy sector. However, the effects of management practices, particularly nitrogen fertilization, on productivity and soil organic carbon (SOC) are difficult to understand, especially when considering that continuous harvesting cycles may have cumulative effects on the crop and its resources use capacity. The objective of this study was to evaluate the effects of different N fertilization levels on biomass production and SOC accumulation of giant reed over 16 years. Every year, starting from the second one, two N fertilization rates were applied: 80 (N80) and 160 (N160) kg N ha−1. The control treatment (N0) was unfertilized. Nitrogen content and use capacity, and SOC gains were determined. Mean 16-year biomass yields were 16.2, 17.1, and 19.5 Mg ha−1 in the N0, N80, and N160 treatments, respectively. Variable yielding phases were observed in the N160 treatment with declining yields towards the last sampling season, whereas the N0 was characterized by increasing yields up to the fourth growing season; thereafter, declining yields were observed. Nitrogen concentration and removed N in the aboveground harvested biomass increased from N0 to N160 and as the stand become older. Mean total SOC stock gains were 1.0 and 0.6 Mg C ha−1 year−1 in the N160 and N0 treatments, respectively. The largest SOC stocks were found in the topsoil, with the largest amount (12 Mg C ha−1 in 16 years) in the N160 treatment. In conclusion, long-term high N fertilization rates result in marginal increments in biomass productivity (about 3 Mg ha−1 year−1), but in substantial increments in SOC, especially in surface soil layers. A farmer might prefer to grow giant reed without the burdens of fertilization despite the seemingly benefits on SOC and lower yields of unfertilized plots
An Integrated Approach to Harvest and Storage of Sweet Sorghum at Farm Scale
Full text linkA major constrain for sweet sorghum (Sorghum bicolor L. Moench) establishment as a reliable biofuel feedstock is the fast biomass degradation immediately after harvest due the high content of soluble sugars and their rapid fermentation that considerably decrease the actual ethanol yield. Such a drawback does not allow storing of sorghum for a reasonable period forcing the industry to process it immediately with consequent problems of handling, logistic, and plant size. Therefore, an appropriate harvesting and storage technique to prevent sweet sorghum juice degradation is urgently needed to ensure economic benefits to farmers. An efficient and cost-effective way to overcome this obstacle could be an on-farm storing system of undistilled ethanol from sweet sorghum juice, while the remaining bagasse could be ensiled and exploited for complementary energy generation. The objective of this study was to evaluate different harvest methods and storage techniques aiming to a low cost and efficient on-farm processing systems to store sweet sorghum biomass. Harvesting in the hard dough stage and defoliating the plants before juice extraction resulted in higher ethanol yield. The use of commercially available fructophilic yeasts allows maximizing undistilled ethanol yield and on-farm storing for about 1 year without spoilage. The residual bagasse was ensiled and inoculated with Lactobacillus bacteria commonly used in forage conservation which significantly improved its quality as feedstock for biogas fermenters. In conclusion, the integration of low-cost harvesting and storage techniques with the valorization of sweet sorghum by-products are worthwhile management strategies to be further developed
Conclusive Results of the European Project OPTIMA: Optimization of Perennial Grasses for Biomass Production in the Mediterranean Area
No full textThe European Project OPTIMA–Optimization of Perennial Grasses for Biomass Production in the Mediterranean Area (GA 289642, coordinated by the University of Catania)–was conceived with the ambitious aim of identifying and optimizing new strategies for the sustainable use of land in marginal Mediterranean areas particularly exposed to climate change. Curiously, although today the term “marginal land” is on everyone’s lips, there is no clear definition for it [1]. Generally speaking, marginal land is considered as a land of low-opportunity cost where it is not worth cultivating food crops; however, the degree of marginality remains vague and complex to estimate as it strongly depends on context and domain. Rabbinge [2], for example, provided an agronomic definition of marginal lands basing on crop growth, Van Orshoven [3] defined marginal land in terms of biophysical constrains, and the FAO [4] proposed an economic perspective of marginal land. An enlightening review article on the definition of marginal land has been submitted during the OPTIMA project by Soldatos and collaborators (under review)
Harvest storage and handling of round and square bales of giant reed and switchgrass: An economic and technical evaluation
No full textThis study evaluated an innovative collection system for biomass based on single-pass harvesting to reduce handling and storage costs. Trials were conducted on two herbaceous perennials: giant reed (Arundo donax L.) and switchgrass (Panicum virgatum L.). A technical and economic evaluation compared two single-pass harvesting systems in which the biomass was cut-shredded-baled in the same operation. The two systems were composed of a Nobili biotriturator (for biomass shredding and windrowing) front-mounted on a 4-wheel-drive tractor and two types of balers: a KUHN VB2160 round baler and a KUHN LSB 1290 large square baler. Costs of harvesting, handling, storage and delivery to the conversion plant were evaluated. Three distances of delivering were considered (0-20; 20-40; 40-60 km). It was estimated that the harvesting system could produce round bales of switchgrass and giant reed stored in-field under a plastic tarp at a cost of 22.3 (sic) Mg-1 and 23.3 (sic) Mg-1 dry and square bales at 26.0 (sic) Mg-1 and 21.7 (sic) Mg-1 for switchgrass and giant reed respectively. The costs of harvesting, handling, in-field storage and delivery to the conversion plant amounted to 43.7 (sic) Mg-1 and 45.7 (sic) Mg-1 dry for round bales and 43.1 (sic) Mg-1 dry and 34.9 (sic) Mg-1 for square bales of switchgrass and giant reed for delivery distances of less than 20 km. (C) 2015 Elsevier Ltd. All rights reserved
Model Simulation of Cumulative Carbon Sequestration by Switchgrass (Panicum Virgatum L.) in the Mediterranean Area Using the DAYCENT Model
No full textLiterature lacks large-scale studies on cumulative C storage capacity of perennial grasses in Europe. At the same time, there is raising interest toward growing biomass crops in Europe, especially under marginal lands of the Mediterranean basin. In the present study, we used the DAYCENT model to estimate the potential of switchgrass (Panicum virgatum L.) as a bioethanol crop to store soil C in the Mediterranean basin. Two scenarios were simulated: (i) cultivation only on heathlands, shrublands, and pastures (1.76 Mha) and (ii) cultivation on heathlands, shrublands, and pastures, plus 5 % of arable lands currently used for cereals (2.97 Mha in total). Cumulative biomass resulted in 184 and 303 Mt over 15 years, while soil organic carbon (SOC) storage values were 6.1 and 12.4 Mt, respectively. Mean annual biomass yield ranged between 5.6 and 9.4 Mg ha−1, while annual SOC accumulation was 0.02 to 0.62 Mg ha−1. Fossil fuel displacement resulted in 54 and 89 Mt of C, i.e., 198 and 327 Mt of equivalent CO2 in the first and second scenarios, respectively. In the second scenario, switchgrass SOC storage was much more pronounced. However, a loss of 54 Mt of grain commodities was also caused by switchgrass cultivation on 5 % of arable lands with consequent indirect land use change (ILUC) effects. The latter were, however, quite low (16 %) when compared to environmental benefits as stored SOC
Land-use change from poplar to switchgrass and giant reed increases soil organic carbon
No full textSwitchgrass and giant reed can provide a dual contribution in reducing greenhouse-gas emissions through displacing fossil fuels and derivatives and increasing soil organic carbon. However, if it is generally true that displacing fossil fuels with biomass brings favorable effects, there is not as much evidence that perennial grasses increase soil organic carbon, as it mainly depends on the land-use change. The present study investigated, for the first time, the effects on soil organic carbon of the land-use change from poplar to switchgrass and giant reed. We addressed the soil organic carbon variation over 10 years of switchgrass and giant reed succeeding a 30-year poplar. Soil samplings were performed after 3 and 10 years from establishment down to 0.6 m depth. The results show that although the ability of poplar to store large quantities of soil C is widely demonstrated, the two perennial crops allowed to further increase soil organic carbon stocks; particularly, giant reed increased soil organic carbon at a double rate than switchgrass (0.19 and 0.09 g kgâ1 yearâ1). The variation in soil organic carbon highly affected total greenhouse gas savings as estimated by a life-cycle assessment: 11â35 and 20â42% of total savings from switchgrass and giant reed, respectively, derived from increasing soil C stocks. These results highlight the importance of understanding long-term environmental- and crop-specific land-use-change effects in life-cycle assessments instead of applying coefficients to generic crop categories (e.g., perennial tree/crop) and crop sequences, as it normally happens
The bio-based economy can serve as the springboard for camelina and crambe to quit the limbo
Full text linkSocial, economic and environmental importance of bio-based economy is rapidly growing and
vegetable oils play an important role. About 75% of global production of vegetable oils
derives from commodity oilseeds (i.e., soybean, oil palm, rapeseed),
while the remaining 25% is produced from minor oilseeds characterized by unusual fatty
acid composition. The present review aims at analyzing the potentialities of two
alternative oilseed crops for Europe, camelina (Camelina sativa) and
crambe (Crambe abyssinica), identified as major candidates for the future
European bio-based economy as testified by the recently funded EU Project (Horizon 2020)
COSMOS (Camelina and crambe Oil crops as Sources of Medium-chain Oils for Specialty
oleochemicals). The interest on camelina and crambe is mainly due to their unique fatty
acid profile, low input management and wide environmental adaptability. We attempted to
analyze pros and cons of development of camelina and crambe in Europe in the light of
biorefinery concept (i.e., using oil and whole produced biomass) as
undertaken by COSMOS project
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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