共查询到20条相似文献,搜索用时 15 毫秒
1.
Brian K. Richards Cathelijne R. Stoof Ian J. Cary Peter B. Woodbury 《Bioenergy Research》2014,7(3):1060-1062
Growing bioenergy feedstocks can provide a long-term sustainable production system for marginal land resources and is essential for minimizing food vs. fuel competition for prime croplands. However, the term “marginal” is too often used in research reports without being defined. We here suggest that clearly specifying the biophysical factors and agroeconomic context contributing to marginality will greatly enhance the utility and comparability of published research. 相似文献
2.
3.
R. B. Mitchell M. R. Schmer W. F. Anderson V. Jin K. S. Balkcom J. Kiniry A. Coffin P. White 《Bioenergy Research》2016,9(2):384-398
Dedicated energy crops and crop residues will meet herbaceous feedstock demands for the new bioeconomy in the Central and Eastern USA. Perennial warm-season grasses and corn stover are well-suited to the eastern half of the USA and provide opportunities for expanding agricultural operations in the region. A suite of warm-season grasses and associated management practices have been developed by researchers from the Agricultural Research Service of the US Department of Agriculture (USDA) and collaborators associated with USDA Regional Biomass Research Centers. Second generation biofuel feedstocks provide an opportunity to increase the production of transportation fuels from recently fixed plant carbon rather than from fossil fuels. Although there is no “one-size-fits-all” bioenergy feedstock, crop residues like corn (Zea mays L.) stover are the most readily available bioenergy feedstocks. However, on marginally productive cropland, perennial grasses provide a feedstock supply while enhancing ecosystem services. Twenty-five years of research has demonstrated that perennial grasses like switchgrass (Panicum virgatum L.) are profitable and environmentally sustainable on marginally productive cropland in the western Corn Belt and Southeastern USA. 相似文献
4.
The anticipated 2014 launch of three full-scale corn stover bioenergy conversion facilities is a strong US market signal that cellulosic feedstock supplies must increase dramatically to supply the required biomass in a sustainable manner. This overview highlights research conducted by the USDA-Agricultural Research Service Renewable Energy Assessment Project (now known as the Resilient Economic Agricultural Practices) team as part of the National Institute for Food and Agriculture Sun Grant Regional Feedstock Partnership Corn Stover team. Stover and grain yield, soil organic carbon, soil aggregation, greenhouse gas, energy content of the stover, and several other factors affecting the fledgling bioenergy industry are addressed in this special issue of the journal. 相似文献
5.
Ethanol fuel can be produced renewably from numerous plant and waste materials, but harnessing the energy of lignocellulosic feedstocks has been particularly challenging in the development of this alternative fuel as a substitute for petroleum-based fuels. Consolidated bioprocessing has the potential to make the conversion of biomass to fuel an economical process by combining enzyme production, polysaccharide hydrolysis, and sugar fermentation into a single unit operation. This consolidation of steps takes advantage of the synergistic nature of enzyme systems but requires the use of one or a few organisms capable of producing highly efficient cellulolytic enzymes and fermenting most of the resulting sugars to ethanol with minimal byproduct formation while tolerating high levels of ethanol. In this review, conventional ethanol production, consolidated bioprocessing, and simultaneous saccharification and fermentation are described and compared. Several wild-type and genetically engineered microorganisms, including strains of Clostridium thermocellum, Saccharomyces cerevisiae, Klebsiella oxytoca, Escherichia coli, Flammulina velutipes, and Zymomonas mobilis, among others, are highlighted for their potential in consolidated bioprocessing. This review examines the favorable and undesirable qualities of these microorganisms and their enzyme systems, process engineering considerations for particular organisms, characteristics of cellulosomes, enzyme engineering strategies, progress in commercial development, and the impact of these topics on current and future research. 相似文献
6.
?zgül Persil ?etinkol Andreia M. Smith-Moritz Gang Cheng Jeemeng Lao Anthe George Kunlun Hong Robert Henry Blake A. Simmons Joshua L. Heazlewood Bradley M. Holmes 《PloS one》2012,7(12)
Eucalypt species are a group of flowering trees widely used in pulp production for paper manufacture. For several decades, the wood pulp industry has focused research and development efforts on improving yields, growth rates and pulp quality through breeding and the genetic improvement of key tree species. Recently, this focus has shifted from the production of high quality pulps to the investigation of the use of eucalypts as feedstocks for biofuel production. Here the structure and chemical composition of the heartwood and sapwood of Eucalyptus dunnii, E. globulus, E. pillularis, E. urophylla, an E. urophylla-E. grandis cross, Corymbia citriodora ssp. variegata, and Acacia mangium were compared using nuclear magnetic resonance spectroscopy (NMR), X-ray diffraction (XRD) and biochemical composition analysis. Some trends relating to these compositions were also identified by Fourier transform near infrared (FT-NIR) spectroscopy. These results will serve as a foundation for a more comprehensive database of wood properties that will help develop criteria for the selection of tree species for use as biorefinery feedstocks. 相似文献
7.
8.
Srabani Das Karin Teuffer Cathelijne R. Stoof Michael F. Walter M. Todd Walter Tammo S. Steenhuis Brian K. Richards 《Bioenergy Research》2018,11(2):262-276
The control of soil moisture, vegetation type, and prior land use on soil health parameters of perennial grass cropping systems on marginal lands is not well known. A fallow wetness-prone marginal site in New York (USA) was converted to perennial grass bioenergy feedstock production. Quadruplicate treatments were fallow control, reed canarygrass (Phalaris arundinaceae L. Bellevue) with nitrogen (N) fertilizer (75 kg N ha?1), switchgrass (Panicum virgatum L. Shawnee), and switchgrass with N fertilizer (75 kg N ha?1). Based on periodic soil water measurements, permanent sampling locations were assigned to various wetness groups. Surface (0–15 cm) soil organic carbon (SOC), active carbon, wet aggregate stability, pH, total nitrogen (TN), root biomass, and harvested aboveground biomass were measured annually (2011–2014). Multi-year decreases in SOC, wet aggregate stability, and pH followed plowing in 2011. For all years, wettest soils had the greatest SOC and active carbon, while driest soils had the greatest wet aggregate stability and lowest pH. In 2014, wettest soils had significantly (p?<?0.0001) greater SOC and TN than drier soils, and fallow soils had 14 to 20% greater SOC than soils of reed canarygrass + N, switchgrass, and switchgrass + N. Crop type and N fertilization did not result in significant differences in SOC, active carbon, or wet aggregate stability. Cumulative 3-year aboveground biomass yields of driest switchgrass + N soils (18.8 Mg ha?1) were 121% greater than the three wettest switchgrass (no N) treatments. Overall, soil moisture status must be accounted for when assessing soil dynamics during feedstock establishment. 相似文献
9.
The cultivation of microalgae gained high attention within the last years because of their potential to substitute conventional bioenergy crops. To evaluate algal bioenergy production pathways already at an early stage, several life cycle assessment (LCA) studies have been performed, but their results and conclusions vary drastically. Against this background, this review gives a comparative analysis of 16 recent studies. To allow for a comparison, a meta-approach served to uniform the considered systems. System boundaries have been equalized and the energy return on investment (EROI) has been calculated for each study. Depending on the assumptions made on biomass productivity, lipid content, required energy, and the output of the system, the energetic performance was assessed. Large variations from 0.01 to 3.35 for the EROI could be derived. 相似文献
10.
11.
Evaluation of Integrated Anaerobic Digestion and Hydrothermal Carbonization for Bioenergy Production
M. Toufiq Reza Maja Werner Marcel Pohl Jan Mumme 《Journal of visualized experiments : JoVE》2014,(88)
Lignocellulosic biomass is one of the most abundant yet underutilized renewable energy resources. Both anaerobic digestion (AD) and hydrothermal carbonization (HTC) are promising technologies for bioenergy production from biomass in terms of biogas and HTC biochar, respectively. In this study, the combination of AD and HTC is proposed to increase overall bioenergy production. Wheat straw was anaerobically digested in a novel upflow anaerobic solid state reactor (UASS) in both mesophilic (37 °C) and thermophilic (55 °C) conditions. Wet digested from thermophilic AD was hydrothermally carbonized at 230 °C for 6 hr for HTC biochar production. At thermophilic temperature, the UASS system yields an average of 165 LCH4/kgVS (VS: volatile solids) and 121 L CH4/kgVS at mesophilic AD over the continuous operation of 200 days. Meanwhile, 43.4 g of HTC biochar with 29.6 MJ/kgdry_biochar was obtained from HTC of 1 kg digestate (dry basis) from mesophilic AD. The combination of AD and HTC, in this particular set of experiment yield 13.2 MJ of energy per 1 kg of dry wheat straw, which is at least 20% higher than HTC alone and 60.2% higher than AD only. 相似文献
12.
Alternative Oils Tested as Feedstocks for Enzymatic FAMEs Synthesis: Toward a More Sustainable Process
下载免费PDF全文

Belén Infanzón Silvia Cesarini Josefina Martínez F. I. Javier Pastor Pilar Diaz 《Biotechnology progress》2017,33(5):1209-1217
Previously isolated and characterized Pseudomonas lipases were immobilized in a low‐cost MP‐1000 support by a re‐loading procedure that allowed a high activity per weight of support. Immobilized LipA, LipC, and LipCmut lipases, and commercial Novozym® 435 were tested for fatty acid methyl ester (FAMEs) synthesis using conventional and alternative feedstocks. Triolein and degummed soybean oils were used as model substrates, whereas waste cooking oil and M. circinelloides oil were assayed as alternative, low cost feedstocks, whose free fatty acid (FFA), and acylglyceride profile was characterized. The reaction conditions for FAMEs synthesis were initially established using degummed soybean oil, setting up the best water and methanol concentrations for optimum conversion. These conditions were further applied to the alternative feedstocks and the four lipases. The results revealed that Pseudomonas lipases were unable to use the FFAs, displaying a moderate FAMEs synthesis, whereas a 44% FAMEs production was obtained when M. circinelloides oil was used as a substrate in the reaction catalysed by Novozym® 435, used under the conditions established for degummed soybean oil. However, when Novozym® 435 was tested under previously described optimal conditions for this lipase, promising values of 85 and 76% FAMEs synthesis were obtained for waste cooking oil and M. circinelloides oil, respectively, which might result in promising, nonfood, alternative feedstocks for enzymatic biodiesel production. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1209–1217, 2017 相似文献
13.
Clementina Dellomonaco Carlos Rivera Paul Campbell Ramon Gonzalez 《Applied and environmental microbiology》2010,76(15):5067-5078
Although lignocellulosic sugars have been proposed as the primary feedstock for the biological production of renewable fuels and chemicals, the availability of fatty acid (FA)-rich feedstocks and recent progress in the development of oil-accumulating organisms make FAs an attractive alternative. In addition to their abundance, the metabolism of FAs is very efficient and could support product yields significantly higher than those obtained from lignocellulosic sugars. However, FAs are metabolized only under respiratory conditions, a metabolic mode that does not support the synthesis of fermentation products. In the work reported here we engineered several native and heterologous fermentative pathways to function in Escherichia coli under aerobic conditions, thus creating a respiro-fermentative metabolic mode that enables the efficient synthesis of fuels and chemicals from FAs. Representative biofuels (ethanol and butanol) and biochemicals (acetate, acetone, isopropanol, succinate, and propionate) were chosen as target products to illustrate the feasibility of the proposed platform. The yields of ethanol, acetate, and acetone in the engineered strains exceeded those reported in the literature for their production from sugars, and in the cases of ethanol and acetate they also surpassed the maximum theoretical values that can be achieved from lignocellulosic sugars. Butanol was produced at yields and titers that were between 2- and 3-fold higher than those reported for its production from sugars in previously engineered microorganisms. Moreover, our work demonstrates production of propionate, a compound previously thought to be synthesized only by propionibacteria, in E. coli. Finally, the synthesis of isopropanol and succinate was also demonstrated. The work reported here represents the first effort toward engineering microorganisms for the conversion of FAs to the aforementioned products.Concerns about climate change and the depletion and cost of petroleum resources have ignited interest in the establishment of a bio-based industry (5, 49, 61), and the conceptual model of a biorefinery has emerged (27, 28, 45). Given its abundance in nature, the carbohydrate portion of edible crops such as sugarcane, sugar beet, maize (corn), and sorghum is currently used as the primary feedstock in the biological production of fuels and chemicals (12, 49, 52). Although the use of nonedible lignocellulosic sugars has been proposed as an efficient and sustainable avenue to the aforementioned processes, the availability of fatty acid (FA)-rich feedstocks and recent progress in the development of oil-accumulating organisms make FAs an attractive alternative. Edible oil-rich crops such as rapeseed, sunflower, soybean, and palm are currently available and widely used as feedstocks for chemical conversion to biodiesel (6), while oleaginous algae and nonedible FA-rich crops along with industrial by-products are receiving greater attention as longer-term alternatives. These nonedible FA-rich feedstocks are presently generated in large amounts and can be exploited for the biological production of fuels and chemicals (14, 22, 51, 56, 57). Unfortunately, microbial platforms to enable this are at present almost absent.FAs not only are abundant but also offer several advantages when used for fuel and chemical production. For example, their metabolism to the key intermediate metabolite acetyl coenzyme A (acetyl-CoA) is very efficient, as it results in 100% carbon recovery (Fig. (Fig.1).1). Since many fuels and chemicals can be derived from acetyl-CoA, high yields can be realized if FAs are used as the carbon source. In contrast, sugar metabolism generates one molecule of carbon dioxide (or formate) per molecule of acetyl-CoA, limiting the yield of products derived from acetyl-CoA (Fig. (Fig.1).1). The product yield advantage of FAs over sugars is also supported by the more highly reduced nature of their carbon atoms. Table Table11 provides a comparison of maximum theoretical yields, on both weight and carbon bases, for the production of biofuels and biochemicals from FAs and lignocellulosic sugars. Maximum theoretical yields have been calculated from stoichiometry based on the pathways shown in Fig. Fig.11 for the utilization of FAs and glucose, the synthesis of products, the tricarboxylic acid (TCA) cycle, and oxidative phosphorylation. The stoichiometric coefficients were obtained by conducting elemental balances on carbon, hydrogen, and oxygen, and an ATP balance was also included in the analysis. As an example, when production of biofuels (e.g., ethanol and butanol) is considered, utilization of FAs (e.g., palmitic acid [C16:0]) as a substrate returns product yields 2.7-fold (wt/wt) or 1.4-fold (C/C) higher than those for sugars (calculations are provided for glucose but are equally valid for other lignocellulosic sugars). Although the current prices of feedstocks on a weight basis are comparable (lower than 20¢/pound), the data reported in Fig. S1a in the supplemental material show that the price per carbon for glucose derived from corn is remarkably higher. Regardless of the basis used for calculations (i.e., weight or carbon basis), when maximum theoretical yields and costs of FA and sugar feedstocks are accounted for, the advantages of using FAs are remarkable (see Fig. S1b in the supplemental material).Open in a separate windowFIG. 1.Pathways engineered in E. coli for the conversion of fatty acids to fuels (red) and chemicals (green). Also shown is the catabolism of fatty acids via the β-oxidation pathway (orange) and of glucose through the Embden-Meyerhof-Parnas pathway (blue). Relevant reactions are represented by the names of the genes coding for the enzymes (E. coli genes unless otherwise specified in parentheses as follows: C. acetobutylicum, ca; C. beijerinckii, cb): aceA, isocitrate lyase; aceB, malate synthase A; adc, acetoacetate decarboxylase (ca); ackA, acetate kinase; adh, secondary alcohol dehydrogenase (cb); adhE, acetaldehyde/alcohol dehydrogenase; adhE2, secondary alcohol dehydrogenase (ca); atoA and atoD, acetyl-CoA:acetoacetyl-CoA transferase; atoB, acetyl-CoA acetyltransferase; bcd, butyryl-CoA dehydrogenase (ca); crt, crotonase (ca); etfAB, electron transfer flavoprotein (ca); fadA, 3-ketoacyl-CoA thiolase; fadB, enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase; fadD, acyl-CoA synthetase; fadE, acyl-CoA dehydrogenase; hbd, β-hydroxybutyryl-CoA dehydrogenase (ca); icd, isocitrate dehydrogenase; pta, phosphate acetyltransferase; sdhABCD, succinate dehydrogenase; scpA, methylmalonyl-CoA mutase; scpB, methylmalonyl-CoA decarboxylase; scpC, propionyl-CoA:succinate CoA transferase; sucA, 2-oxoglutarate dehydrogenase; sucB, dihydrolipoyltranssuccinylase; and sucCD, succinyl-CoA synthetase. Abbreviations: 2[H] = NADH = FADH2 = QH2 = H2; P/O, amount of ATP produced per oxygen consumed in the oxidative phosphorylation.
Open in a separate windowaStoichiometry is based on the pathways shown in Fig. Fig.11 for the utilization of FAs and glucose, the synthesis of products, the TCA cycle, and oxidative phosphorylation. For the synthesis of biochemicals, CO2 fixation via the Wood-Ljungdahl pathway (50) (2CO2 + ATP + 8[H] → acetyl-CoA) or the carboxylation of phosphoenolpyruvate (54) (phosphoenolpyruvate + CO2 → oxaloacetate + ATP) were also considered (not shown in Fig. Fig.1).1). The stoichiometric coefficients were obtained by conducting elemental balances on carbon, hydrogen, and oxygen. An ATP balance was also included in the analysis for the reactions shown in italics. All other reactions represent ATP-generating pathways. Every acetyl-CoA oxidized through the TCA cycle generates three NADH, one reduced flavin adenine dinucleotide (FADH2), and one ATP equivalent. Eleven ATPs can be generated from the oxidation of the NADH and FADH2 produced in the TCA cycle (two and three ATPs per FADH2 and NADH, respectively) via coupling between the electron transfer chain and oxidative phosphorylation.Despite the aforementioned advantages, biological conversion of FA-rich feedstocks has been exploited only for the production of polyhydroxyalkanoates (46, 47), with no report to date of organisms engineered for the conversion of FAs to fuels and chemicals (see the text in the supplemental material for more details).Escherichia coli is one of the most amenable organisms to industrial applications and has been engineered for biofuel production (52). The utilization of FAs in E. coli is mediated by enzymes encoded by the fad regulon and the ato operon (11) (Fig. (Fig.1).1). Products of the fad regulon mediate the transport, acylation, and β-oxidation of medium-chain (C7 to C11) and long-chain (C12 to C18) FAs. Two additional enzymes encoded by the atoD-atoA and atoB genes (part of the atoDAEB operon) are also required for the growth of E. coli on short-chain (C4 to C6) FAs (25). The expression of the fad regulon and ato operon is controlled by FadR (fadR) and AtoC (atoC), respectively (44).While advantageous, the high degree of reduction of carbon in FAs also poses a metabolic challenge because their average degree of reduction per carbon is higher than in biomass. Therefore, the incorporation of fatty acids into cell mass generates reducing equivalents (Fig. (Fig.1)1) and hence requires the presence of an external electron acceptor. That is, the aforementioned pathways are active only in the respiratory metabolism of FAs, which leads to the synthesis of cell mass and carbon dioxide but no other metabolic product. Therefore, fuel and chemical production from FAs requires the engineering of a respiro-fermentative metabolic mode that would support the synthesis of fermentative products during respiratory metabolism of FAs. To this end, we metabolically engineered native and heterologous pathways for the efficient catabolism of FAs and the synthesis of fuels and chemicals in E. coli. Biofuels, commodity chemicals, and polymer building blocks were chosen as model products to illustrate the feasibility of the proposed approach. 相似文献
TABLE 1.
Comparison of maximum theoretical yields for the production of biofuels and biochemicals from fatty acids (palmitic acid) and lignocellulosic sugars (glucose)Pathway stoichiometry for the synthesis of the specified product from glucose (C6H12O6) or palmitic acid (C16H32O2)a | Maximum yield (wt basis/C basis) |
---|---|
Biofuels | |
Ethanol (C2H6O) | |
C6H12O6 → 2C2H6O + 2CO2 | 0.51/0.67 |
C16H32O2 → 23/3C2H6O + 2/3CO2 | 1.38/0.96 |
C16H32O2 + 51/7H2O → 53/7C2H6O + 6/7CO2 + 8/7[H]; 8/7[H] + 2/7O2 → 4/7H2O | 1.36/0.95 |
Butanol (C4H10O) | |
C6H12O6 → C4H10O + 2CO2 +H2O | 0.41/0.67 |
C16H32O2 + 7/2H2O → 53/14C4H10O + 6/7CO2 + 8/7[H]; 8/7[H] + 2/7O2 → 4/7H2O | 1.10/0.95 |
Biochemicals | |
Acetate (C2H4O2) | |
C6H12O6 + 2H2O → 3C2H4O2 | 1.00/1.00 |
C16H32O2 + 7H2O + 7CO2 → 23/2C2H4O2 | 2.70/1.44 |
Acetone (C3H6O) | |
C6H12O6 → 3/2C3H6O + 3/2CO2 + 3/2H2O | 0.48/0.75 |
C16H32O2 + 5/4H2O + 5/4CO2 → 23/4C3H6O | 1.30/1.08 |
Isopropanol (C3H8O) | |
C6H12O6 → 4/3C3H8O + 2CO2 + 2/3H2O | 0.44/0.67 |
C16H32O2 + 40/9H2O → 46/9C3H8O + 2/3CO2 | 1.20/0.96 |
Succinate (C4H6O4) | |
C6H12O6 + 6/7CO2 → 12/7C4H6O4 + 6/7H2O | 1.12/1.14 |
C16H32O2 + 152/17CO2 + 86/17H2O → 106/17C4H6O4 + 80/17[H]; 80/17[H] + 20/17O2 → 40/17H2O | 2.87/1.56 |
Propionate (C3H6O2) | |
C6H12O6 → 12/7C3H6O2 + 6/7CO2 + 6/7H2O | 0.70/0.86 |
C16H32O2 + 262/83CO2 + 370/83H2O → 530/83C3H6O2 + 216/83[H]; 216/83[H] + 54/83O2 → 108/83H2O | 1.81/1.20 |
14.
15.
Alisa W. Coffin Timothy C. Strickland William F. Anderson Marshall C. Lamb Richard R. Lowrance Coby M. Smith 《Bioenergy Research》2016,9(2):587-600
With global increases in the production of cellulosic biomass for fuel, or “biofuel,” concerns over potential negative effects of using land for biofuel production have promoted attention to concepts of agricultural landscape design that sustainably balance tradeoffs between food, fuel, fiber, and conservation. The Energy Independence Security Act (EISA) of 2007 mandates an increase in advanced biofuels to 21 billion gallons in 2022. The southeastern region of the USA has been identified as a contributor to meeting half of this goal. We used a GIS-based approach to estimate the production and N-removal potential of three perennial biofeedstocks planted as conservation buffers (field borders associated with riparian buffers, and grassed waterways) on the Coastal Plain of Georgia, USA. Land cover, hydrology, elevation, and soils data were used to identify locations within agricultural landscapes that are most susceptible to runoff, erosion, and nutrient loss. We estimated potential annual biomass production from these areas to be: 2.5–3.5 Tg for giant miscanthus (Miscanthus?×?giganteus), 2–8.6 Tg for “Merkeron” napier grass (Pennisetum purpureum), and 1.9–7.5 Tg for “Alamo” switchgrass (Panicum virgatum). When production strategies were taken into consideration, we estimated total biomass yield of perennial grasses for the Georgia Coastal Plain at 2.2–9.4 Tg year?1. Using published rates of N removal and ethanol conversion, we calculated the amount of potential N removal by these systems as 8100–51,000 Mg year?1 and ethanol fuel production as 778–3296 Ml year?1 (206 to 871 million gal. US). 相似文献
16.
17.
18.
19.
Karla A. Hernández Vance N. Owens Arvid Boe José L. González-Hernández Dokyoung Lee Ezra Aberle 《Bioenergy Research》2018,11(2):440-448
Prairie cordgrass (Spartina pectinata, Link.) has been evaluated for its biomass potential because of its high yield, relatively low nutrient demand, and diverse geographical adaptation. Our objectives were to determine (1) biomass production potential of prairie cordgrass in South Dakota and Kansas under varying nitrogen levels, (2) the effect of N on prairie cordgrass yield components (tillers m?2 and tiller mass), and (3) the effect of N on yield and N concentration of belowground biomass. Older stands of Red River prairie cordgrass (RR-PCG) in South Dakota and Atkins prairie cordgrass (AT-PCG) in Kansas were fertilized with 0, 56, 112 and 168 kg N ha?1 from 2008 to 2011 in South Dakota and in 2009 and 2010 in Kansas. Experimental design at all locations was a 4?×?4 Latin square. Prairie cordgrass was harvested around a killing frost in October and early November. Biomass production ranged from 5.50 to 13.69 Mg ha?1 in South Dakota and 5.33 to 12.51 Mg ha?1 in Kansas. Prairie cordgrass yield did not increase significantly with N application at any location or year. Across years, tiller density ranged from 536 to 934 tillers m?2 for RR-PCG in South Dakota and from 234 to 315 tillers m?2 for AT-PCG in Kansas. Neither tiller density or tiller mass was affected by N rate at any location in any year. Belowground biomass production to a depth of 25 cm was equal to or greater than aboveground biomass. However, it was not affected by N rate in all locations by any year. Understanding prairie cordgrass nitrogen-use dynamics to improve biomass and nutrient management will be essential for future investigations. Findings of this study are important to support the notion that prairie cordgrass biomass production in two different environments can be achieved with minimal N inputs. 相似文献
20.
M. Hammad Nadeem Tahir Michael D. Casler Kenneth J. Moore E. Charles Brummer 《Bioenergy Research》2011,4(2):111-119
Reed canarygrass, Phalaris arundinacea L., produces high biomass yields in cool climates and wetlands. The number and timing of harvests during a growing season directly affect biomass yield and biofuel quality. In order to determine optimum harvest management, seven cultivars of reed canarygrass were planted in field experiments at Ames, IA; McNay, IA; and Arlington, WI in the upper Midwestern USA and harvested once in autumn or in winter, twice in spring + autumn or spring + winter, or three times during the season as hay. Biomass yield varied considerably among harvest treatments, locations, and years, ranging up to 12.6 Mg ha?1. Dry matter percentage ranged from 37% for spring-harvested biomass to 84% for overwintered biomass. The three harvest hay and two harvest spring + autumn managements produced the highest biomass yield compared to other systems, but the advantage, if any, of hay management was small and probably does not justify the cost of additional fieldwork. More mature biomass, such as that found in the single harvest systems, had higher fiber concentrations. Overwintered biomass had superior biofuel quality, being low in P, K, S, and Cl and high in cell wall concentration. However, winter harvest systems had lower yield than autumn harvest and in some years, no harvest was possible due to lodging from snow compaction. The main limitation of a two harvest system is the high moisture content of the late spring/early summer biomass. 相似文献