薄膜和太阳能保温技术在草莓高架栽培中的应用

【目的】研究不同薄膜和太阳能保温技术在草莓高架栽培中的保温效果,并与地面高垄栽培相比较,寻找最佳的保温组合,为草莓高架式栽培在我国的推广奠定基础。【方法】以优良草莓品种“红颜”为试材,以地面高垄栽培为对照(CK),对高架栽培设5个薄膜保温处理（无薄膜帘披垂(CK1),外帘黑色薄膜、无内帘(T1),外帘白色薄膜、无内帘(T2),外帘白色薄膜、内帘黑色薄膜(T3),外帘黑色薄膜、内帘白色薄膜(T4）),对其中保温效果最好的处理进行太阳能热水保温（T5）,测定不同处理不同时间点(06:00开始,每隔3 h测定1次,连续测定3 d)的基质和土壤下0.05,0.10,0.15和0.20 m的温度及各处理的室内温度（CK、CK1的温室内温度,T1～T4的帘内温度）,并测定各处理果实的单果质量、最大单果重量、单株产量、可溶性固形物含量和硬度。【结果】各薄膜保温处理在09:00-18:00的保温效果差异较小,但在保温要求较高的21:00-次日06:00,各处理的保温效果差异较大,其中T3处理不同深度的基质温度均高于或显著高于其他处理,其基质的平均温度为18.4 ℃,室内平均温度为17.4 ℃。在对温度要求较高的18:00-次日06:00,T5处理不同深度的基质温度及室内温度明显高于其他处理,二者呈一定的正相关关系。T3、T5 处理的草莓果实经济性状均显著高于CK。【结论】T3处理（外帘白色薄膜、内帘黑色薄膜）对冬季草莓高架栽培的保温效果最佳;冬季低温期,利用滴管输送太阳能热水对基质増温效果明显。采取披垂薄膜帘和输送太阳能热水这2种措施能解决冬季草莓高架栽培中的保温问题,可以确保草莓在寒冷的冬季能正常生长发育。     

一个山区农场生态农业系统的分析与评价

供试农场生态农业系统由加工业，牲猪，沼气池，桔园，鱼池和农田６个系统组成。本文运用“黑箱理论”和方法，对６个子系统的投入能量，产出能量，能量效益及投能结构进行了分析。全系统的能量产投科为０．８１，光能利用率为１．５５％，产品能与总投能之比为３７．８％，单位产值含能量为１８８．３ＧＪ／万元，系统投入的有机能占总投能的９５％。从系统的Ｎ素循环和动态平衡分析表明：农田，桔园的Ｎ素输入均大于输出，Ｎ素处于     

Competition for electron donors among nitrate reducers,ferric iron reducers,sulfate reducers,and methanogens in anoxic paddy soil

Slurries of anoxic paddy soil were either freshly prepared or were partially depleted in endogenous electron donors by prolonged incubation under anaerobic conditions. Endogenous NO ₃ ^– was reduced within 4 h, followed by reduction of Fe³⁺ and SO ₄ ^2– , and later by production of CH₄. Addition of NO ₃ ^– slightly inhibited the production of Fe²⁺ in the depleted but not in the fresh paddy soil. Inhibition was overcome by the addition of H₂, acetate, or a mixture of fatty acids (and other compounds), indicating that these compounds served as electron donors for the bacteria reducing NO ₃ ^– and/or ferric iron. Addition on NO ₃ ^– also inhibited the reduction of SO ₄ ^2– in the depleted paddy soil. This inhibition was only overcome by H₂, but not by acetate or a mixture of compounds, indicating that H₂ was the predominant electron donor for the bacteria involved in NO ₃ ^– and/or SO ₄ ^2– reduction. SO ₄ ^2– reduction was also inhibited by exogenous Fe³⁺, but only in the depleted paddy soil. This inhibition was overcome by either H₂, acetate, or a mixture of compounds, suggesting that they served as electron donors for reduction of Fe³⁺ and/or SO ₄ ²⁺ . CH₄ production was inhibited by NO ₃ ^– both in depleted and in fresh paddy soil. Fe³⁺ and SO ₄ ^2– also inhibited methanogenesis, but the inhibition was stronger in the depleted than in the fresh paddy soil. Inhibition of CH₄ production was paralleled by a decrease in the steady state concentration of H₂ to a level which provided a free enthalpy of less than G=–17 kJ mol^-1 CH₄ compared to more than G=–32 kJ mol^-1 CH₄ in the control. The results indicate that in the presence of exogenous fe³⁺ or SO ₄ ²⁺ , methanogenic bacteria were outcompeted for H₂ by bacteria reducing Fe³⁺ or SO ₄ ²⁺ .Deceased on 27 December 1992     

包膜尿素不同用量对黄瓜幼苗生长及氮平衡的影响

为确定合理的包膜尿素用量以指导黄瓜育苗施肥,采用生产中常用的草炭:蛭石(2:1)为育苗基质,研究了包膜尿素不同用量对黄瓜幼苗生长、养分吸收及氮平衡的影响。结果表明:包膜尿素用量在125~375 mg N/株的情况下,可协调黄瓜幼苗地上部和地下部的生长,促进幼苗对磷、钾的吸收;移栽时,基质中的氮素残留总量90.5~250.3 mg N/株,其中,残留的包膜氮素占75.4%~82.3%,可实现带肥移栽;育苗期间可产生31.9~121.5 mg N/钵的氮素表观损失。     

筒式风能采集系统及其试验研究

为了克服现有技术中风能采集装置对风速或风向适应能力不足、风能利用率不高的问题,提出了一种适合城市高空风能利用的新型筒式垂直轴风力发电系统,其不仅具有很强的风向适应能力,而且能够在较低风速时,充分利用导风板将风力集中到筒式风能采集系统内,提高了风轮利用风能的效率。这种风力发电系统将与城市高层建筑构成一体化,充分利用高空风能优势进行发电,噪音小,不会给城市的生活和工作带来影响。介绍了该筒式风能采集系统的主要组成部分,以及实验结果,初步证实了该设计的可行性。     

新农村住宅中太阳能采暖研究

结合新农村住宅用综合能源价格法对太阳能地板采暖与常规热源进行经济效益对比,还对太阳能采暖进行节能效益分析、环保效益分析,得出太阳能采暖在新农村建设中值得推广的结论。     

智能化太阳能密集烤房节能效果研究

智能化太阳能密集烤房由太阳能供热系统、煤燃烧供热系统、装烟系统、通风排湿系统和自动控制系统等部分构成。通过智能化太阳能密集烤房与普通密集烤房的烟叶烘烤试验,结果表明:烘烤下部烟叶,历时118 h,其中3 d晴天,1 d雨天,1 d阴天,最大光照强度13.60×104lux,智能化太阳能密集烤房烘烤一炕烟叶较对照节煤198.6 kg,节煤效果达25.6%;烘烤中部烟叶,历时138 h,均为晴天,最大光照强度15.20×104lux,智能化太阳能密集烤房烘烤一炕烟叶较对照节煤123.2 kg,节煤效果达36.1%;烘烤上部烟叶,历时146 h,其中1 d阴天,其余为晴天,最大光照强度12.80×104lux,智能化太阳能密集烤房烘烤一炕烟叶节煤255.0 kg,节煤效果达35.6%。智能化太阳能密集烤房与对照烘烤各炕次烟叶的耗电量则无显著差异,智能化太阳能密集烤房的节能减排效果主要表现在节煤上。     

Evaluation of surface water drainage systems for cropping in the Central Highlands of Ethiopia

In Ethiopia vertisols cover about 10% of the total land area and is the fourth most important soil used for crop production, accounting for nearly 23% of the total arable land used for crop production. More than half of the vertisols are found in the Central Highlands of Ethiopia, with an altitude of more than 1500 m above mean sea level. The unique physical and chemical properties of these soils and the high rainfall during the main cropping season create severe surface waterlogging problems which hinder crop production activities. Severe surface waterlogging affects the growth of plants by impeding nutrient uptake and creating oxygen deficiency around the root zone. To address this crop production problem, three surface water drainage methods, namely broad bed and furrow (BBF), ditch, and flat (traditional) methods were evaluated using the water balance of the plant root zone and wheat as a test crop. The experiment was conducted at the Ginchi Research Station in the central highlands of Ethiopia over two consecutive seasons (2000 and 2001). The results showed that both the BBF and the ditch drainage methods gave about 33% and 22% more grain yield than the flat treatment, respectively. However, there were no significant differences between BBF and ditch for both grain and biomass yield during both experimental seasons. During both seasons the total water balance (ΔW_r) at the root zone especially, in the months of June, July and August on all the treatments was higher than the crop water requirement (ETc) and showed no significant difference between the treatments. Thus, the results of this study indicated that the soil water in the root zone was not significantly altered by surface drainage systems and therefore implies the need of further improvement of the different surface drainage methods regarding improving the waterlogging condition and hence the productivity of the vertisols in the Central Highlands of Ethiopia.     

花椒林地不同地面覆盖的水热效应研究

花椒(Zanthoxylumbungeanum)为芸香科(Rutaceae)花椒属落叶灌木或小乔木,是重要的调味品、香料及木本油料树种。我国花椒主产于四川、甘肃、陕西、山东、河北、河南等省,栽培历史悠久(曾京京,2000)。花椒耐干旱瘠薄,根系发达,表层根系密度大,水平根的分布大于冠幅3~4倍(余晓林,2003),因而是山区生态造林的重要树种。近年来,在退耕还林项目中被列为生态经济树种,在发展山区经济中发挥了重要作用(魏玉君等,1996;何腾兵等,2000)。研究(李洪钵等,1991;曹彬等,2002)表明,通过施肥、整形修剪等措施可提高花椒的产量。然而,目前花椒园土壤管理中仍…     

不同突扩比下空间淹没水跃的水力计算

突扩能够使局部范围内水流紊动剧烈,可以作为水利工程中消能工的一种重要方式．为了探讨突扩比对下游流体水力特性的影响规律,基于RNG k-ε紊流模型和PISO压力-速度耦合算法,采用非均匀结构网格技术,建立了三维紊流数学模型,对突扩比分别为1000,0833,0.667,0500,0333等5种空间水跃进行了多工况数值模拟,结合试验数据,计算结果量纲一化,讨论了不同突扩比大小对下游水力性能的影响,并分析了下游流速、紊动能及消能率等随突扩比的变化规律．数值计算结果表明:突扩比对下游流速、紊动能及消能率影响显著,突扩比越小,下游流速变化越显著,主流在空间内扩散愈迅速,流态转变越明显;随着突扩比的减小,紊动应力愈小,紊动能量愈小,而消能率越大;突扩水跃较典型水跃消能效果明显增强,当突扩比小于0500时,消能率增大不再显著．