发展生物质产业

介绍了当今全球性能源危机中生物质产业的特殊意义及发达国家在发展生物基产品（biobased products）、生物燃料（biofuels）和生物能源（bioenergy）方面的动向。对发展中国的生物质产业提出了具体建议,包括建设年产5000万t的绿色油田和开辟农业的“第三战场”。     

以菊芋粉为原料同步糖化发酵生产燃料乙醇

利用粟酒裂殖酵母（Schizosaccharomyces pombe）能发酵菊芋未水解糖液高产乙醇的特点提出了以菊芋粉为原料,同步糖化发酵生产燃料乙醇的新工艺。在摇瓶中考察了原料预处理方法、原料浓度和初始pH值对乙醇发酵的影响,进而在5 L发酵罐中考察了未调控pH值和恒定pH值与通气情况对乙醇发酵的影响。结果表明：该菌株最适pH值为4.0;100目筛分的菊芋粉发酵效果良好,115℃灭菌处理优于121℃,在此条件下,菊芋粉浓度200 g/L时,乙醇产量达到66.58 g/L,理论转化率为85.88%;发酵液pH值下降对乙醇发酵没有影响,通入适量氧气会导致乙醇产量的下降,这表明粟酒裂殖酵母进行乙醇发酵时不需要供氧;通入氮气保持厌氧环境不能显著提高乙醇产量,不通气进行乙醇发酵也达到高的转化率,因此在工业生产中,不必保持厌氧发酵环境。在此基础上,对菊芋粉补料发酵进行了试验,补料至菊芋粉终浓度为300 g/L,发酵终点乙醇浓度为94.81 g/L,理论转化率为81.54%。这些研究工作,为以菊芋为原料的燃料乙醇工业化生产提供技术依据。     

国内外生物质能发展综述

生物质能源是仅次于石油、煤炭和天然气的世界第4大能源,具有可再生和环境友好的双重属性,其发展对社会经济可持续发展具有重要意义.为此,通过对目前生物质能主要研究领域以及国内外生物质能实践发展的分析,提出了我国发展生物质能战略意义及对策,为我国生物质能的发展提供参考依据.     

柳枝稷和坚尼草的耐镉性初步研究

为了探究镉污染条件下开发能源植物的可行性,以高生物量黍属能源植物柳枝稷和坚尼草为材料,温室中苗期水培试验,分别对柳枝稷外源施加浓度为0,0.5,5,10,20,50,100μmol/L镉(Cd),对坚尼草施加浓度为0,2,5,7.5,10μmol/L Cd,从形态、生长生理等角度,分析两种能源草对镉的响应。结果表明:随Cd浓度的增加,柳枝稷和坚尼草生物量和根伸长量均下降,Cd浓度为50μmol/L时,柳枝稷根鲜重减少达显著水平(P0.05)。而坚尼草则在Cd浓度为2μmol/L时,根和地上部分总鲜重减少达显著水平。相比于对照,Cd浓度为2μmol/L时,坚尼草的根伸长量已下降96.3%,而柳枝稷在5μmol/L Cd时根伸长量才降低55.0%,柳枝稷的耐镉性高于坚尼草。经20μmol/L镉处理,柳枝稷的地上部镉浓度达40mg/kg,生物量下降了45%。不同浓度的镉处理下,镉在柳枝稷体内的迁移指数为5.9%~14.2%,柳枝稷可以在Cd污染条件下被开发为能源和修复植物种植。此外,实验还发现,在根平均直径为0~1mm范围内,柳枝稷的总根长、根表面积和根体积与镉积累呈显著负相关,与迁移指数呈显著正相关(P0.05),该结果说明,细根在植物的镉吸收积累和转运中可能起着非常重要的作用。     

Economic and Life-Cycle Analysis of Forest Carbon Sequestration and Wood-Based Bioenergy Offsets in the Central Hardwood Forest Region of United States

This study investigates the combined impact of carbon and bioenergy markets on upland oak dominated mixed hardwood forests in the Central Hardwood Forest Region (CHFR) of the United States. A modification of the Hartman model was used for the economic analysis of carbon sequestration and using wood-based biomass for bioenergy. A life-cycle assessment was used to determine the amount of carbon sequestered due to stand growth and emitted during harvesting and decay of wood products. Two scenarios were taken, one where additionality of carbon is considered and the other where it is not. Sensitivity analysis was done with the range of carbon and bioenergy prices. The results show that net carbon payments have more impact on land expectation value (LEV) when additionality is not considered; in contrast, bioenergy payments have more impact on LEV when additionality is considered. Carbon and bioenergy prices also influenced the amount of stand level supply of forest products and carbon in both scenarios. In general, sawtimber, wood bioenergy, and carbon supply increased with an increase in carbon prices, whereas, pulpwood supply decreased. With few exceptions at higher carbon prices, bioenergy supply decreased with the increase in wood bioenergy prices, showing a backward bending supply curve in both scenarios.     

边际土地草本能源植物应用潜力评价

为促进中国边际土地草本能源植物种植与生物质原料生产,基于京郊边际土地草本能源植物规模化种植的实践,从生产潜力、生物质品质、生物质利用潜力、生态效应等4个方面对荻的应用潜力进行了分析评价.结果表明:荻在京郊挖沙废弃地上的生产潜力为2.31 t/hm2,达到京郊耕地条件下的8.41％,生物质品质优良,其标准煤折算当量、沼气产量、纤维素乙醇产量分别为1.42 t/hm2、289.99 m3/hm2、0.59 t/hm2,分别达到京郊耕地条件下的8.38％、8.37％、8.15％,生态效应明显.荻在边际土地上具备良好的应用潜力.     

Biochar‐compost substrates in short‐rotation coppice: Effects on soil and trees in a three‐year field experiment

Both biochar and compost may improve carbon sequestration and soil fertility; hence, it has been recommended to use a mixture of both for sustainable land management. Here, we evaluated the effects of biochar–compost substrates on soil properties and plant growth in short rotation coppice plantations (SRC). For this purpose, we planted the tree species poplar, willow, and alder in a no‐till field experiment, each of them amended in triplicate with 0 (= control) or 30 Mg ha^?1 compost or biochar–compost substrates containing 15% vol. (TPS15) and 30% vol. biochar (TPS30). For three years running, we analyzed plant growth as well as soil pH, potential cation exchange capacity (CEC), stocks of soil organic carbon (SOC), total N, and plant‐available phosphate and potassium oxide.Biochar‐compost substrates affected most soil properties only in the topsoil and for a limited period of time. The CEC and total stocks of SOC were consistently elevated relative to the control. After three years the C gain of up to 6.4 Mg SOC ha^?1 in the TPS30 plots was lower than the added C amount. Especially in the case of TPS30 treatment, C input was characterized by the greatest losses after application, although the black carbon of the biochar was not degraded in soil. Additionally, tree growth and woody biomass yield did not respond at all to the treatments. Overall, there were few if any indications that biochar–compost substrates improve the performance of SRC under temperate soil and climate conditions. Therefore, the use of biochar for such systems is not recommended.     

芒和荻作为草本能源植物的潜力分析

利用多年生草本植物发展生物质能源产业是可再生能源发展的一个新方向。研究发现,芒和荻是我国本土多年生高大C4草本植物,具有作为能源植物的开发潜力,在欧洲已被广泛应用,在我国仅仅用于水土保持、造纸、饲料等。该文综述了芒和荻的生物学特征、生物质品质特性、生态效益、国内外利用现状,认为该类植物具有生态类型多、野生资源丰富、适应性广,抗逆性强,产量高,净能产出高,生物质品质好,转化利用途径广,生态价值好等特点,是优良的草本能源植物,适合在我国边际土地上种植利用,目前的研究重点应集中于种质资源的搜集、评价和新品种选育及适用于边际土地的栽培管理技术。     

Population Dynamics of Aphthona whitfieldi (Coleoptera: Chrysomelidae), Pest of Jatropha curcas,and Environmental Factors Favoring Its Abundance in Burkina Faso

The flea beetle Aphthona whitfieldi Bryant (Coleoptera: Chrysomelidae) is the main pest of the bioenergy crop Jatropha curcas L. (Euphorbiaceae) in Burkina Faso and several other West African countries. Adults severely defoliate plants, resulting in seedling mortality, poor growth, and low yields. To study the population dynamics of the pest in the Sissili Province of Burkina Faso, 12 sites were monitored weekly during a year and 31 sites were inspected for damage at the peak period of insect abundance. The effect of cropping systems (hedge, intercropping, and monoculture) and surrounding vegetation on population densities of A. whitfieldi was assessed. Beetles were rarely found in the dry season and peaked in the second half of the rainy season. The cropping system did not significantly influence the abundance and attack level. In contrast, the close vicinity of fallow lands seems to increase damage levels. Many aspects of the biology and ecology of A. whitfieldi remain to be investigated before sustainable control methods can be developed. However, this study already allows us to propose recommendations for further research on management.     

Influence of leaching on the chemical composition of grassland biomass for combustion

Bioenergy production from grassland biomass is an alternative use for semi‐natural grasslands, but chemical composition of grassland herbage can limit its suitability for combustion. Leaching by precipitation during the field period is currently used to remove unwanted elements from other herbaceous biofuels. The aims of this study were to assess the influence of leaching on chemical composition of grassland biomass, to establish the influence of leaching intensity and to evaluate the feasibility of a simplified laboratory method for leaching studies. Freshly cut and dried herbage from two contrasting grasslands were leached using 12 and 36 mm of simulated rain. A second experiment compared three methods of different leaching intensity. Leaching resulted in strong reduction in Cl and K concentrations; ash was moderately reduced and Mg slightly reduced. Concentrations of N, S and Ca were not affected. Leaching occurred in dried, but not in fresh herbage, and Cl leaching was affected by herbage type. Cl, K and ash responded differently to increased leaching intensity. Slagging, fouling and corrosion problems during combustion, which are closely linked to Cl and K concentrations, could be reduced by natural leaching under suitable weather conditions. A standardized laboratory leaching method is suggested for further investigating the influence of herbage characteristics on the leachability of K and Cl.