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The cultivation of energy cane throughout the Southeastern United States may displace grazed pastures on organic soil (Histosols) to meet growing demands for biofuels. We combined results from a field experiment with a biogeochemical model to improve our understanding of how the conversion of pasture to energy cane during early crop establishment affected soil GHG (CO 2 , CH 4 , and N 2 O) exchange with the atmosphere. GHG fluxes were measured under both land uses during wet, hot and cool, dry times of year, and following a fertilization event. We also simulated the impact of changes in precipitation on GHG exchange. Higher fertilization of cane contributed to greater emission of N 2 O than pasture during warmer and wetter times of the year. The model predicted that energy cane emitted more nitrogen than pasture during simulated wetter than drier years. The modeled emission factor for N 2 O was 20 to 30-fold higher than the default value from IPCC (1%), suggesting that the default IPCC value could dramatically underestimate the consequences of this land conversion on the climate system. Predicted soil CH 4 and CO 2 fluxes were higher in pasture than energy cane, and this difference was not affected by increasing precipitation. Model simulations predicted that soils under first year cane emit more GHGs than pasture, particularly during wet years, but this difference disappeared two years after energy cane establishment. Our results suggest that management practices may be important in determining soil GHG emissions from energy cane on organic soils particularly during the first year of cane establishment. [ABSTRACT FROM AUTHOR]

The use of woody biomass in thermochemical conversion is still the most popular method of obtaining bioenergy from this material. Elemental composition has a significant effect on biomass quality and parameters of the combustion process. The aim of this study was to determine the content of selected macroelements (phosphorus, potassium, magnesium, calcium, sodium and sulphur), microelements (boron, copper, iron, manganese and zinc) and trace elements (cadmium, chromium, nickel and lead) in willow biomass of two different varieties and three clones, harvested in annual, biennial and triennial cycles in north-eastern Poland. The study found significant variability between varieties/clones and harvest cycles. Biomass of the UWM 200 clone of Salix alba in triennial harvest rotation had the best parameters as a potential fuel source; it was found to contain the significantly smallest concentrations of P, K, Na, S (1.48, 5.45, 0.08, 0.35 g kg −1 DM, respectively) and Fe, Cr, Pb (208.85, 4.91, 0.83 mg kg −1 , respectively). The content of all of the elements under study decreased significantly with an extended harvest cycle, and the differences, when comparing the triennial to the annual cycle, ranged from −9% to −29% for macroelements, from −7% to −48% for microelements and from −11% to −20% for trace elements. [ABSTRACT FROM AUTHOR]

This paper makes projections of the theoretical and technical potentials of bioenergy supply for 2050. The projections consider changes in available land for bioenergy and food for the global demand and advancements in yield, productivity, expansion of bio-waste recovery, and energy conversion. We present a literature review on projections. We introduced a novel logical and transparent forecasting model. Three future scenarios were established: business as usual (BUS), optimistic trends (OPT), and full adaptation response (FAR). The projection is carried out based on four adjusting factors. An uncertainty analysis was carry-out based on a Monte-Carlo method. Projections of bioenergy production in 2050 were compared with other projections in the literature. The FAR scenario showed that it would be possible to produce twenty-one times the current primary bioenergy supply and to even supply all global primary energy demand in 2050, mostly by energy crops. The assumptions adopted for the BUS and OPT scenarios make their projections more likely. Therefore, the contribution of bioenergy in the global energy matrix is expected to be between 64 and 313 EJ (7.5%–37%) in 2050. There would be a significant change in the composition of the bioenergy supply from today's mostly firewood to energy crops and biowastes. The technical potential for fuel and electric power mostly follow the supply trends for primary bioenergy (theoretical). The potential avoided greenhouse emissions are estimated. The heuristics and the level of transparency of the novel model will allow adjustments and exploration of other scenarios as time passes. • Novel model for projections of the potential of global primary bioenergy supply. • Bioenergy supply potential is shown for 11 different groups of biomass. • Global primary bioenergy supply could increase up to 6 times by 2050 (37% of demand). • Full adaptation response scenario could meet 100% of the global energy demand. • Bioenergy can play a major role in the global energy supply. [Display omitted] [ABSTRACT FROM AUTHOR]

Literature values for glucose release from corn stover are highly variable which would likely result in tremendous variability in bio-refinery ethanol yield from corn stover feedstock. A relatively recent change in United States corn genetics is the inclusion of the Bacillus thuringiensis (Bt) trait, which now accounts for three-fourths of all US planted corn acreage. The objective of this study was to evaluate the effect of corn grain yield, inclusion of the Bt trait, and location environment on corn stover quality for subsequent ethanol conversion. Two hybrid pairs (each having a Bt and non-Bt near-isoline) were analyzed giving a total of 4 hybrids. In 2010 and 2011, field plots were located in Michigan at four latitudinal differing locations in four replicated plots at each location. Stover composition and enzymatic digestibility was analyzed and estimated ethanol yield (g g −1 ) was calculated based on hydrolyzable glucan and xylan levels. Analysis showed that there were no significant differences in total glucose or xylose levels nor in enzymatically hydrolyzable glucan and xylan concentrations between Bt corn stover and the non-Bt stover isolines. Regression analyses between corn grain yield (Mg ha −1 ) and corn stover ethanol yield (g g −1 ) showed an inverse relationship indicative of a photosynthate source-sink relationship. Nevertheless, the quantity of stover produced was found to be more critical than the quality of stover produced in maximizing potential stover ethanol yield on a land area basis. [ABSTRACT FROM AUTHOR]