生物质燃烧技术综述

燃烧作为生物质能源转化的一种成熟技术，具有低成本、低风险和高效率等优越性。该文集中论述了有关生物质燃烧技术的各种观点与问题。首先，介绍了生物质燃料的物理和化学特性；其次，论述有关生物质燃烧和混合燃烧技术，其中生物质燃烧主要形式为层燃、下饲式、流化床和悬浮燃烧，生物质与煤的混合燃烧主要形式为直接利用和气化利用；然后，讨论有关灰分熔点较低而引起结渣、积灰和腐蚀等问题；最后，介绍生物质燃烧对环境的影响及最新研究现状。     

生物质的产量和贸易概述

生物质能源是一种可再生、低污染、分布广泛的清洁能源。基于此,介绍了生物质能源的贡献、生物质产量、贸易形式和发展潜力,并对生物质能源的发展进行了展望,以期为市场参与者和政策制定者提供参考。     

能源草发展的比较优势和战略潜力研究

纤维素类生物质已经成为发展生物质能源的主导原料。草本能源植物以其独具的优点在生物质原料中居重要地位,具有广阔的发展前景。针对能源替代、环保减排的迫切要求及生物质能源发展原料需求,分析了我国发展能源草的重要性和必要性,论述了能源草作为新型生物质原料的优势和潜力。     

气相温度脉动对非球形生物质颗粒焦炭燃烧的影响

将生物质颗粒与煤粉混合燃烧,可以有效地利用生物质能。生物质颗粒通常形状很不规则,有着较大的长径比,非球形特性较为明显。对于在燃烧室内运动与燃烧的生物质颗粒,气相湍流脉动是否会对非球形生物质颗粒的燃烧反应过程产生作用有待探讨。该文研究了气相温度脉动对热气流中非球形生物质颗粒瞬时焦炭燃烧的影响,给出了不同气相平均温度和颗粒长径比下生物质颗粒瞬时质量和瞬时焦炭燃烧速率随时间的变化。研究表明气相温度脉动对不同长径比的生物质颗粒的焦炭燃烧过程均有明显的影响,导致颗粒质量下降变快,焦炭燃尽时间变短。气相温度脉动幅度的增加进一步加快了不同长径比颗粒瞬时质量的下降。该文的研究揭示了气相温度的湍流脉动对非球形生物质颗粒瞬时焦炭燃烧过程的作用,这种作用并不会因为颗粒长径比的变化而发生改变。     

西藏贡嘎县生物质能源燃烧甲烷和氧化亚氮排放量估算

参照国际政府间气候变化研究小组推荐的方法，对西藏贡嘎县生物质能源燃烧甲烷的氧化亚氮的排放量进行了估算，结果表明，西藏贡嘎县生物质能源燃烧排放甲烷及氧化亚氮的总量分别为１１６７５２－２１６８４９ｋｇ和１０９４．４－５１９４．４ｋｇ。     

废弃生物质材料的高附加值再利用途径综述

现代工业的发展在促进人类社会物质文明繁荣的同时,导致了大量生物质资源的浪费。随着环境、能源等问题日益突出,废弃生物质资源的再利用研究越来越受到关注。该文在介绍废弃生物质材料丰富来源与传统处理方法的基础上,根据近几年的研究现状及发展趋势,就其循环利用途径进行了详细综述。废弃生物质材料主要来源于农业生产废弃物、农副产品与食品加工废弃物、林业与城市绿化废弃物及生活垃圾。废弃生物质材料的处理已经从传统方法(包括燃烧法、饲料化、肥料化与基质化处理),逐步走向能源化、生态化、材料改性,以及制备基于生物炼制技术的新型生物基功能与智能材料产品。总之,以废弃生物质材料为主要原料,开发新型基质与功能材料是发展趋势。     

生物质成型燃料燃烧设备结渣特性试验研究

本文采用生物质成型燃料双层炉排燃烧设备,分别进行了炉膛温度、燃料层厚度、燃料粒径和过量空气系数等对结渣率影响的试验,得出了生物质成型燃料燃烧设备的结渣特性。根据试验与观察,分析了生物质成型燃料燃烧设备的结渣过程及结渣影响因素,并总结了生物质成型燃料燃烧设备的结渣成因。     

生物质炭对土壤物理性质影响的研究进展

生物质炭在农业与环境中的应用已成为近期国内外研究热点,有关生物质炭特性以及生物质炭对土壤化学、生物学性质和作物产量的影响,已经有一些综述,但是生物质炭对土壤物理性质影响的相关综述很少。本文对近10年生物质炭对土壤物理性质影响相关的研究成果进行了整理分析。研究结果发现生物质炭可以降低土壤容重,提高土壤团聚体稳定性,增加田间持水量和土壤有效水含量,降低饱和导水率等。生物质炭影响土壤物理性质的主要原因是生物质炭具有较大的比表面积和孔隙度。此外,生物质炭与土壤矿质颗粒结合,并通过对土壤微生物活性和植物生长的影响间接影响土壤物理性质。生物质炭对土壤物理性质的影响与多种因素有关,如生物质炭原料、裂解温度、施用量和颗粒大小,土壤质地和处理时间等。关于生物质炭对土壤物理性质影响的长期研究很少,且缺乏田间试验。因此,将来的研究应更加倾向于长期田间条件下生物质炭对土壤物理性质的影响,并逐渐发现生物质炭的作用机理,为实际的农业生产和生态治理提供科学依据。     

草本类生物质与烟煤混烧特性及其影响因素分析

为了研究草本类生物质与烟煤的混烧特性,在空气气氛下分别对甜菜根、柳枝稷与烟煤的混烧特性进行热重试验,分析升温速率和质量配比对混烧特征参数的影响,并与纯烟煤的燃烧特征进行比较。结果表明:混合样品的着火温度远低于烟煤,但略高于纯生物质的着火温度,随着升温速率的提高,混合燃料着火温度逐渐提高。当生物质质量比例大于20%时,提高升温速率才能有效提高混烧样品的挥发分释放性能和综合特性指数,升温速率一定,生物质质量比例越大,混烧样品的挥发分释放特性指数和综合特性指数也越大,生物质质量比例为80%,升温速率为50℃/min时,混合样品有较好的燃烧性能。在10～90℃/min的升温速率范围内,柳枝稷混烧样品的燃烧特征参数均大于甜菜根混烧样品。研究结果可以为生物质与烟煤混合燃料的高效燃烧提供参考。     

生物质灰肥特性及对杨梅生长发育与果实品质的影响

生物质灰肥是利用生物质燃烧残渣开发的一种富含矿质营养元素的肥料。本文分析了4种原料生物质灰渣的特性,研究了生物质灰肥对杨梅(以荸荠种和东魁种为供试品种)生长发育和品质的影响。结果表明:生物质灰渣富含K、Si、Ca、Mg等营养元素,重金属含量符合国家标准。相同总养分含量条件下,生物质灰肥处理较杨梅专用肥和普通复合肥及对照处理明显提高杨梅坐果率与优质果比例,并使总可溶性固形物及糖含量较对照和普通复合肥处理显著上升;可滴定酸含量、Vc含量、单果重与其他3个处理差异显著,果实品质明显改善;东魁杨梅、荸荠杨梅的单株产量增幅最高分别可达26%、27%;同时,施用生物质灰肥能促进早熟。因此,将生物质灰肥用于杨梅生产可以提高其品质,并减少生物质灰渣对环境的污染。     

提高小麦光能利用效率机理的研究进展

农作物产量依赖于生物量和收获指数，过去作物产量的增加主要得益于收获指数的增加而生物量增加很小，进一步提升作物产量在很大程度上依赖于生物量的提高，而光能利用效率是提高作物生物量的瓶颈。小麦（Triticum aestivum L.）是一种在全世界广泛种植的谷类作物，可为全世界人口提供约20.0%的能量，阐明小麦光能利用效率变化的内在机理与外在因素，对提高作物资源利用效率和生产力有重要意义。本文对光能利用效率的定义、主要过程、小麦的光能利用特性和内外影响因素进行综述，表明提高光能利用效率具有较大的潜力；论述了外部因素，即光、水分、养分和耕作制度等对小麦光能利用效率的影响，主要表现为在单株尺度上主要由光合作用等内部因素控制，而在田间尺度则由温度、降水、耕作栽培方式等非生物因素控制。进一步分析了目前存在的问题以及在气候变化背景下小麦的适应机制，旨在为提升小麦光能利用效率提供理论依据。未来光能利用效率的研究可利用高通量表型观测技术，与分子标记结合，设计在目标环境下的具有高光能利用效率的理想株型，为培育高产高效小麦品种提供科学依据。     

基于作物产量反应和农学效率的推荐施肥方法

当前农民过量和不平衡施用化肥现象严重,导致肥料利用率降低,影响到农田的可持续利用。因此,发展适合我国农业生产特点的养分管理和施肥方法尤为重要。本文介绍了基于作物产量反应和农学效率的推荐施肥新方法,该方法是以改进的SSNM （Site-specific Nutrient Management）和改进的QUEFTS （Quantitative Evaluation of the Fertility of Tropical Soils）模型为指导的养分管理和推荐施肥为原则,同时考虑大、中微量元素的全面平衡,并应用计算机软件技术把复杂和综合的养分管理原则智能化形成可为当地技术推广人员掌握的Nutrient Expert推荐施肥专家系统软件。Nutrient Expert推荐施肥专家系统软件在用户回答一些简单问题后就能给出基于作物栽培管理措施的推荐施肥套餐,包括作物种植密度、目标产量、推荐的养分用量及其可选用的物化的肥料用量,同时根据预知的作物生长季节推荐施肥的最佳时间和次数。通过跨区域田间多点验证试验证明,基于作物产量反应和农学效率的推荐施肥方法是一种简单的易于掌握的作物增产增收、提高肥料利用率和保护环境的新方法。     

不同肥料/改良剂对冷泥田水稻生长、养分吸收及土壤性质的影响

【目的】西南地区冷泥田的水稻生长不良可归因于多种障碍因子,包括土壤物理、化学和生物因子。本文针对冷泥田影响水稻生长的土壤化学障碍因子,研究了不同肥料或改良剂对冷泥田水稻生长、养分吸收和土壤性质的影响,旨在为这类土壤的培肥、改良利用和水稻高产提供科学依据和实用技术。【方法】试验地点选在四川省东南地区冷泥田集中的泸县,试验历时2年。试验设无肥对照(CK)、全量化肥(NPK)、NPK+泥炭(NPK+Pe)、NPK+商品有机肥(NPK+COF)、NPK+鸡粪(NPK+CM)、NPK+硅肥(NPK+Si)、NPK+石灰(NPK+L)、NPK+硅钙肥(NPK+Si Ca),NPK+锌肥(NPK+Zn)9个处理。在水稻收获前采集代表性植株样,调查水稻农艺性状,分析水稻对氮、磷和钾的吸收量;水稻收获后采集土壤样品,测定不同处理的土壤p H、全氮、有效磷、速效钾、有机质、还原性物质总量、活性还原物质以及亚铁和亚锰含量。【结果】结果表明,在所有处理中,NPK+L和NPK+Si Ca处理可改善水稻的产量构成因子,稻谷产量比NPK处理显著提高15.40%和10.64%;而其他处理的增产效果则均不显著。NPK+L和NPK+Si Ca处理的土壤p H明显高于其他处理,土壤还原性物质总量和活性还原物质(含Fe2+和Mn2+)含量显著降低;NPK+L和NPK+Si Ca处理可增加土壤养分的有效性,促进水稻对氮、磷、钾养分的吸收,改善土壤的化学性质。同时,土壤分析结果表明,该试验土壤的有效钙和有效硅均缺乏,而NPK+L和NPK+Si Ca处理增加了土壤的有效钙和有效硅,对提高水稻产量有重要贡献。有机肥对土壤相关性质的影响与石灰和硅钙肥相反,特别是鸡粪。施用锌肥对水稻有一定的增产效果,但差异不显著。水稻收获后土壤中氮、磷、钾养分残留量与施肥量和水稻吸收携出量密切相关。【结论】对长期淹水地势低洼的酸性冷泥田来说,石灰和硅钙肥是比较理想的土壤改良剂,能同时起到改善土壤性质和提高作物产量的效果;而有机肥,特别是未腐熟的有机肥或有机物料,则不宜在冷泥田中施用或大量施用。     

基于产量品质及水肥利用率的袋培辣椒水肥耦合方案

为探究水肥耦合对袋培辣椒产量、果实品质、水分利用效率(Water Use Efficiency,WUE)和肥料利用率(Fertilizer Use Efficiency,FUE)的影响,构建袋培辣椒水肥精准化管理模式,该研究以'博陇(37-94)Bolon RZ F1'辣椒为对象,设3种灌溉水平(基质相对含水量70%～75%(W1)、55%～60%(W2)和40%～45%(W3))、3个营养液浓度水平(设置150%(F1)、100%(F2)、80%(F3)标准山崎辣椒营养液浓度)和2个营养液供应量(正常供应、减量供应(每次辣椒采收前6 d营养液减量40%供应))三因素耦合,共18个处理,分析各因子及其耦合效应,建立综合评价辣椒产量、WUE、FUE及果实综合品质的多目标优化模型,并利用遗传算法多目标优化法对该模型进行寻优。结果表明:灌溉量和营养液浓度单因子及其耦合效应均对辣椒产量、WUE和FUE有显著性影响,产量、WUE和FUE均随灌溉量和营养液浓度的增加先增加后降低;利用Topsis法对各处理的果实品质进行综合评价,营养液减量供应可在维持产量和WUE较高的基础上,显著提高辣椒果实综合品质和FUE;营养液减量供应下W2F2处理的辣椒产量、WUE和FUE最高,营养液减量供应下W2F1处理果实综合品质最好。遗传算法多目标优化法寻优表明营养液减量供应结合W2F2处理效果最佳。该试验条件下,高产优质的袋培辣椒水肥耦合方案为:通过灌溉将基质相对含水量控制在55%～60%,施用100%浓度的标准山崎辣椒营养液,且每次辣椒采收前6d营养液减量40%供应。该模式下的辣椒产量达到87930.52kg/hm2,果实品质综合评价贴合度达到0.742,WUE和FUE分别达到41.14 kg/m3和38.83%,此结果可为辣椒高产优质且水肥科学管理提供指导依据。     

Nutrient Partitioning and Carbon and Nitrogen Mineralization of Switchgrass Plant Parts

Switchgrass (Panicum virgatum L.) is a native warm-season (C₄) grass that has the potential to be used as a bioenergy crop and reduce increases in atmospheric carbon dioxide (CO₂). Continuous production and removal of switchgrass, however, may deplete soil fertility. A strategy of returning plant components higher in nutrients to the field during harvest may help maintain soil fertility. In this study, nutrient partitioning in switchgrass parts over time and their C and N mineralization patterns in soil were determined. Switchgrass (cv. Alamo) was harvested on a biweekly schedule from June to October, with plants from each harvest separated into six parts (top, middle, and bottom leaves and stems) for mineral and fiber analysis. Plant materials from three harvests were used in an incubation study to determine effects of plant component, age, and composition on carbon (C) and nitrogen (N) mineralization. Results indicated that a strategy of returning specific plant parts to the field would not substantially conserve soil nutrients without proportionally decreasing materials available for bioenergy production. Structural components (cell wall and cellulose) were dominant factors affecting the quantity of C mineralized. Approximately 50% of C added as switchgrass was mineralized after 100 days of incubation. Soil N immobilization was observed in all switchgrass plant part treatments.     

Effect of Harvest Timing on Yield and Mineral Nutritional Value of Kabuli Type Chickpea Seeds

Chickpea (Cicer arietinum L.) seeds are a good source of protein and mineral nutrients. However, there is no information regarding harvest timing on yield and mineral composition of chickpea seeds. The effect of harvest timing on seed yield, some yield components and mineral nutritional value of seeds of field grown chickpea plants in two different sites were studied. The mineral composition of chickpea straw depending on harvest timing was also evaluated in order to explain the variations of seed mineral concentrations in sink-source relationship manner. Yield and mineral nutritional value of chickpea were significantly affected by harvest timing. When compared to the seed yield at optimal harvest time, seed yield was 18% and 9% lower in the early harvest and 27% and 31% in the late harvest in Site 1 and Site 2, respectively. Late harvest of chickpea crops resulted in significant pod dropping and shattering. Generally, protein, phosphorus (P), calcium (Ca), magnesium (Mg), copper (Cu), zinc (Zn), and manganese (Mn) concentrations of the seeds in optimal harvest were found to be greater than in early and late harvested plants. Harvest timing also results in significant variations in straw mineral nutrient concentrations of the plants. As the results of this study, it was concluded that the harvest timing is critical for yield losses and mineral nutritional value of chickpea seeds.     

A review of factors that influence the production of quality seed for long-term conservation in genebanks

Seed quality is a critical aspect in agriculture as well as in the long-term conservation of plant genetic resources in genebanks. Since potential seed longevity depends on initial quality, genebank curators need to be aware of the best management practices that contribute to the production of high quality seed during routine germplasm regeneration/multiplication. Among the factors influencing initial seed quality, those related to crop management, including plant nutrient and water supply during crop growth, climatic conditions during seed development and maturation, as well as the harvest and drying practices are of considerable significance. Seeds of high quality can be obtained by planting in suitable areas/fields and at appropriate times, applying good crop management practices, adoption of proper harvesting and drying techniques, careful handling and processing to minimize mechanical injuries and unwanted seed mixing with other accessions, and ensuring minimum deterioration before reaching the designated storage. However, seed production and post-harvest handling highly depend on the biology and agronomy of the species. As germplasm collections contain a wide range of diversity for morphological and agronomic characters and that there might well be critical gaps in knowledge among genebank staff or about the species in question, genebanks may also need to embark on research to gain crop specific knowledge on optimal seed production procedures to improve seed quality.     

播期对麦(油)后直播棉产量、品质及氮磷钾利用的影响

为明确长江流域下游棉区麦(油)后直播棉生产的适宜播期,本研究以?中棉所50‘为材料,于2017—2018年进行大田试验,研究不同播期(5月15日、5月25日、6月4日、6月14日和6月24日)对直播棉产量、品质及养分利用的影响。结果表明,播期推迟,棉花生育进程推迟;花铃期日均温和日照时数降低、有效积温先升高后降低且以6月4日播期花铃期有效积温最高。可见,前3个播期棉花花铃期温光条件较好。棉株与生殖器官的生物量及氮磷钾累积量随播期推迟降低,且前3个播期的棉株生物量和养分累积进入较高速率累积期早于后2个播期的棉株。随着播期的推迟,直播棉成铃数与皮棉产量显著降低。与5月15日播期相比,其余4个播期直播棉的皮棉产量分别降低15.9%～16.9%、13.1%～16.9%、26.9%～33.5%、58.2～62.0%。100kg皮棉氮、磷和钾吸收量随播期推迟而增加,但养分利用效率降低。不同播期间,以6月4日和6月14日播期棉纤维综合品质较优。综上,本试验条件下,5月15日—6月4日是长江流域棉区麦(油)后直播棉获得较高产量的适宜播期,该播期内适当推迟播种有利于棉花优质纤维的形成。     

Yield and chemical composition of five common grassland species in response to nitrogen fertiliser application and phenological growth stage

Abstract

The interaction of grassland management factors such as plant species, rate of nitrogen (N) fertiliser application and stage of maturity at harvest, will determine the optimal balance of herbage yield, nutritive quality and ensilability for ruminant nutrition and/or industrial applications. This study investigated the effects of N fertiliser input and harvest date on the yield and chemical composition of five common grass species, and made comparisons with red clover. Perennial ryegrass (PRG), Italian ryegrass (IRG), tall fescue, cocksfoot, timothy and red clover were grown under two inorganic N fertiliser inputs (0 kg N ha^?1 and 125 kg N ha^?1; except red clover) and harvested at five dates (fortnightly from 12 May to 7 July) in the primary growth. Regression analysis of these data allowed comparison of the yield and chemical composition of each grass species at common growth stages, without the confounding effects of variation in maturity between grass species at common harvest dates. Of the grass species investigated, timothy was most productive in terms of dry matter (DM) yield and thus has the potential to provide a cheaper feed per unit DM. However, the most digestible grass species was PRG, with timothy being the lowest, and this could impact on both animal and bioenergy production potential. The most suitable grass species for ensiling was IRG (particularly when grown without fertiliser N) due to its higher water soluble carbohydrate (WSC) concentration and lower buffering capacity (BC) compared to all other grass species. In comparison to the grasses receiving inorganic N fertiliser, red clover had a numerically lower DM yield, but a higher mean DM digestibility and crude protein concentration. The lower WSC concentration and higher BC of the red clover may result in a greater preservation challenge during ensiling.     

Nutrient Accumulation and Utilization in Rice Under Film‐Mulched and Flooded Cultivation

Abstract

In recent years, plastic film mulched cultivation has been widely used in China as a strategy to reduce irrigation water consumption and increase water use efficiency (WUE). Experiments were conducted to study nitrogen (N), phosphorus (P), and potassium (K) accumulation and utilization in flooded rice comparing plastic film mulched (PFM) and conventionally flooded cultivation (CFC) in two successive years. In comparison with the plants under CFC, the plants under PFM had significantly higher N concentration at booting stage and lower K and P concentrations at heading and maturity stages and N concentrations after booting stage. More N accumulation was found in PMC‐treated plants than in CFC‐treated plants before booting, while thereafter CFC showed a significant increase in nutrient accumulation. N, P, and K accumulation ratios were significantly larger for PFM than for CFC at early stage (before booting), but the trend was just opposite after booting. The PFM‐treated plants substantially showed smaller nutrient accumulation rate through the whole growing process relative to the CFC‐treated plants. Although PFM‐treated plants had significantly higher physiological efficiency (PE) of all three nutrients than the CFC‐treated plants, its fertilizer recovery efficiency (RE) and agronomic nutrient utilization efficiency (AE) was markedly lower due to lower biomass and grain yield. In addition, the PFM‐treated plants had lower P/N and K/N in terms of nutrient accumulation, suggesting the importance to improve the P and K availability in rice film‐mulched cultivation.