我国能源利用效率综合评价研究

引进环境系统建立基于能源-经济-环境的能源利用效率评价指标体系,运用因子分析法和层次分析法分别对我国及我国各地区能源利用效率进行综合评价,发现2种评价方法对同一评价指标体系的评价结果整体上具有一致性和趋同性,从而进一步说明评价结果的可靠性。并根据评价结果发现各地区的能源利用效率水平差距较大,效率水平极不平衡,节能减排潜力巨大。     

能源农业与现代农业发展研究

介绍了能源农业的产生背景、发展现状,阐述了发展能源农业的意义,我国发展能源农业的优势,以及能源农业对现代农业的推进作用。     

基于模糊神经网络的保鲜冷库节能研究

为了克服冷库空调系统的设备频繁启停和系统节能效率不高的问题,针对保鲜冷库制冷系统提出了基于Elman神经网络的模糊控制算法的优化改造,采用不同的温度偏差作为模糊控制系统的输入量,模糊控制规则由Elman神经网络在线学习实时生成,调控优化制冷系统的运行状态。试验数据表明,改进的保鲜冷库系统节能效果明显,提高了运行的平稳性,基本克服了压缩机频繁启动的问题。     

广东省农业生产能源消费碳排放分析及减排对策

[目的]研究广东省农业生产能源消费CO2排放量,并提出可行的减排对策。[方法]基于《中国能源统计年鉴》和《广东统计年鉴》提供的农业终端能源消费数据,采用IPCC推荐的碳排放计算方法,估算了2000～2009年广东省农业生产终端能源消费CO2排放量,并提出了相应的减排措施。[结果]随着农业产值和能源消费的快速增长,2000～2009年广东农业终端能源消费CO2排放总量总体呈不断上升的趋势,从2000年的423.63万t碳增加到2009年的605.99万t碳,年均增长率4.1%;而农业终端能源消费的碳排放强度则不断下降,从2000年的0.424 t碳/万元下降至2009年的0.301t碳/万元,年均下降率为3.7%。农业产值增长、能源利用效率提高、农业能源消费结构高碳化等是农业终端能源消费CO2排放变化的主要影响因素。通过大力开发利用农村可再生能源,开发推广先进的能源利用技术,加快推进农业机械的节能,建立健全农业生产能源消费碳排放的宏观调控机制等措施,可以减少农业生产能源消费的二氧化碳排放量。[结论]该研究为广东省农业生产能源消费碳减排政策的制定提供了依据。     

基于能值分析的闽台农业经济系统的相图法比较研究

运用能值方法,分析了福建和台湾两省农业生态经济系统发展过程中资源利用结构变化情况,以及该变化对各地环境和系统发展的影响。运用相图分析法对系统的发展进程、现状和变化趋势进行了全面系统的比较研究。结果表明,地区经济发展水平较高的台湾,农业生产过程对不可更新反馈能值的依赖更强,所造成的环境压力和对系统可持续性的削弱程度更大。针对存在的问题,提出了加强投资合作、改变传统农业生产模式、加强闽台农业生物科技合作等对策。     

新型制冷技术研究进展

在广泛文献检索基础上,总结了主要的新型制冷技术的制冷原理、特点和发展现状,并对其应用前景进行了展望。     

高粱-苏丹草杂交种的生长特性和光合功能研究

研究了高丹草(Sorghum bicolor×S.sudanense)和苏丹草(Sorghum sudanense (Piper) Stapf.)的生长特性、叶片叶绿素荧光特性及激发能的分配对干旱的响应。结果表明:高丹草的株高、根系长度和干物质积累等明显优于苏丹草,干旱下高丹草地上部相对含水率高于苏丹草。干旱降低了2种牧草叶片的PSⅡ反应中心活性和反应中心开放程度,电子传递速率降低,但高丹草叶片在重度干旱下的电子传递速率高于苏丹草,光抑制程度明显低于苏丹草。干旱下2种牧草叶片的PSⅡ反应中心吸收的光能用于光化学反应的量子产额(Ф_PSⅡ)和依赖于叶黄素循环的能量耗散的量子产额(Ф_NPQ)所占比例呈现降低趋势,但重度干旱下高丹草叶片的Ф_PSⅡ和Ф_NPQ明显高于苏丹草,而 PSⅡ反应中心的热耗散量子产额(Ф_NF)所占比例低于苏丹草,说明高丹草叶片在重度干旱下叶片以叶黄素循环为主的光保护机制在防御光破坏方面发挥着重要作用,从而保证了PSⅡ反应中心的正常生理功能,减轻了高丹草在重度干旱下的光抑制程度。     

脂类与健康饮食

介绍了脂类的生理功能、营养价值以及脂类在主要食物中的含量,提出今后人们在饮食过程中对脂类摄取的见解。     

Lowering carbon footprint of durum wheat by diversifying cropping systems

Improving cropping systems may help mitigate greenhouse gas emissions. This study determined the carbon footprint of durum wheat (Triticum turgidum L.) produced in diverse cropping systems. Durum was grown in rotation systems which had different combinations of oilseed, pulse, and cereal crops at five site-years in Saskatchewan, Canada. Total greenhouse gas emissions from the decomposition of crop residues along with various production inputs were used for the estimation of carbon footprint. On average, emissions from the decomposition of crop straw and roots accounted for 25% of the total emissions, those from the production, transportation, storage, and delivery of fertilizers and pesticides to farm gates and their applications 43%, and emissions from farming operations 32%. Durum wheat preceded by an oilseed crop (Brassica napus or Brassica juncea) the previous year had carbon footprint of 0.33 kg CO₂e kg⁻¹ of grain, or 7% lower than durum in cereal-cereal-durum system. Durum preceded by a biological N-fixing crop (Cicer arietinum chickpea, Lens culinaris lentil, or Pisum sativum pea) the previous year lowered its carbon footprint by 17% compared with durum preceded by a cereal crop. Durum produced in a pulse-pulse-durum system had carbon footprint 0.27 kg CO₂e kg⁻¹ of grain, 34% lower than durum grown in cereal-cereal-durum systems. Diversifying cropping systems with oilseeds and biological N-fixers significantly lowered carbon footprint of durum wheat.     

Accumulation and partitioning of nitrogen,phosphorus and potassium in different varieties of sweet sorghum

This study investigated changes in accumulation and partitioning of nitrogen (N), phosphorus (P), and potassium (K) with harvest dates of early, middle, and late maturity sweet sorghum varieties in 2006 and 2007 in North China. All the varieties exhibited an obvious trend of decrease in concentrations of N, P and K in aboveground plants from elongation to 60 days after anthesis (DAA). The reduction in nutrient concentrations was found in the order of K (14.5 − 4.5 g kg⁻¹) > N (13.3 − 7.4 g kg⁻¹) > P (2.40 − 0.96 g kg⁻¹). Conversely, N, P, and K accumulation significantly increased from elongation to anthesis, and continued to increase until 40 DAA. The accumulation of N, P, and K at maturity (40 DAA) was 128–339 kg ha⁻¹, 30–75 kg ha⁻¹ and 109–300 kg ha⁻¹, respectively. Between elongation and anthesis, the middle and late maturity varieties had a higher ratio of N (50–82%), P (55–83%), and K (62–88%) accumulation than the early varieties (51–64% for N, 40–62% for P, and 55–75% for K). Sweet sorghum exhibited only one important K uptake stage from elongation to thesis according to the accumulation ratio (percentage of the nutrient accumulated at a given stage relative to that at physiological maturity) and rate (kilogram of nutrient accumulated per day per hectare). The stage from anthesis to grain maturity was the second important N and P uptake period. During the delay harvest period between 40 and 60 DAA, the early varieties exhibited significant increases in N accumulation; and the late varieties exhibited the reverse. P accumulation did not decrease significantly, whereas K accumulation decreased for all varieties in both years. Although of the N and P concentrations in straw were significantly lower than in grains, the N, P and K accumulation in straw was 2.2–9.3, 1.7–7.7, and 8.1–30.5 times higher than in grains, respectively. The concentrations of N and P in leaves were higher than in stems after anthesis. We found significantly higher accumulation of P and K in stems than in leaves, with a comparable N accumulation. The findings are helpful to make a fertilization regime recommendation for sweet sorghum production as a bioethanol crop in North China. It also suggests a further genetic improvement for optimizing nutrient use.