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1.
用不同的冬季采暖和夏季降温技术可获得不同的环境条件。该文分别就热风炉采暖、湿帘风机系统降温与火炉采暖自然通风降温的分娩舍、保育舍二种猪舍进行了对比试验。结果表明,试验舍的环境条件明显好于对照舍;试验舍哺乳仔猪断奶成活率冬季、夏季分别为96．37％和95．36％,比对照舍分别提高4．28和6．97％;冬季试验舍保育猪的平均育成率为98．09％,日增重0．409kg／(d·头),分别较对照舍提高5．27％和30．67％,料肉比为1．472:1,下降13．25％,而夏季湿帘风机系统对保育舍猪的生产性能没有明显影响。 相似文献
2.
湿帘-风机系统对北京育肥猪舍的降温效果 总被引：2，自引：4，他引：2
北京市夏季高温将对猪的生产造成严重影响,夏季猪舍环境温度控制尤为重要。该试验研究比较了湿帘-风机和单纯风机在北京猪舍的降温效果,设计了风机风量测量系统并实测了猪舍通风量,每天定时分别测定两猪舍内温度、湿度、风速和舍外温、湿度并进行比较分析。结果表明:试验期间,湿帘-风机猪舍和单纯风机舍6个断面风速范围分别为0.51~0.84和0.51~0.68 m/s,整体风速差异不显著(P0.05)。湿帘-风机舍舍内温度显著低于单纯风机舍(P0.05),湿帘-风机舍和单纯风机舍舍内温度高于30.0℃的小时数占比分别为5.0%和20.2%。湿帘-风机舍同一时刻断面1(湿帘端)温度低于断面6(风机端)温度0.4~2.2℃,单纯风机舍各时刻不同断面的温度差异不显著(P0.05)。单纯风机舍内的猪只呼吸频率均显著高于湿帘-风机舍内呼吸频率3.82次/min(12:00)和3.05次/min(14:00)(P0.05)。湿帘-风机舍降温系统日用水量为1.20~6.27 m~3。北京地区猪舍使用湿帘-风机系统降温效果优于单纯风机降温效果,但湿帘-风机降温将耗用一定水资源。 相似文献
3.
湿帘-风机降温下的温室热/流场模拟及降温系统参数优化 总被引：2，自引：5，他引：2
为提高温室夏季降温环境性能,提出了一种基于计算流体力学(computational fluid dynamics,CFD)的温室湿帘-风机系统的降温环境优化设计方法。采用太阳射线追踪法来模拟太阳辐射对夏季温室内流场环境的影响,并结合温室内作物的多孔介质模型,构建并求解温室三维非稳态模型,模拟了湿帘-风机降温下的温室内部温度场与速度场分布情况。模拟结果与试验测量的温度值和风速值进行了对比,其平均误差分别在4%和6%以内,验证了建立的温室CFD模型的准确性。结合正交试验方法,基于CFD模型对不同温室长度、湿帘面积和风机速度参数条件下的室内降温环境进行了优化设计。根据模拟优化获得的不同配置方案结果,建立了温室长度、湿帘面积和风机速度参数的拟合结果,为夏季华东沿海地区Venlo型温室湿帘-分机降温系统的设计提供了可靠的理论依据。 相似文献
4.
热应激会对猪产生不利影响,为探究猪舍适宜的夏季通风条件和合理的降温需求,该研究利用环境气象资料,结合能质平衡方程,对围护结构传热及通风散热占比进行了分析,构建了保育及育肥舍夏季最大通风量的计算公式,对五大气候区的典型城市：长春、北京、南宁、武汉、贵阳的保育及育肥舍夏季最大通风量取值进行了规范,并对这些城市的110 m×15 m的模型猪舍的热湿环境进行了分析。结果表明,5个地区使用湿帘的时长：南宁>武汉>北京>贵阳>长春;使用湿帘后舍内温度仍高于27 ℃的时长：南宁>武汉>北京>贵阳>长春;使用湿帘后的平均降温幅度：北京>长春>武汉>南宁>贵阳;使用湿帘后平均相对湿度增量：北京>长春>武汉>南宁>贵阳;使用湿帘后舍内温度降至27 ℃以下时间占比：长春>北京>贵阳>武汉>南宁。通过分析以上数据,该研究对五大气候区湿帘降温系统的购置及使用提出了建议,同时该研究为不同气候区商品猪舍的夏季小气候估算及湿帘降温系统运行使用效果评估提供了参考。 相似文献
5.
规模化猪场妊娠母猪舍改进湿帘降温系统的环境特性 总被引：2，自引：1，他引：2
为研究湿帘与地道结合的改进湿帘降温系统对妊娠母猪舍的环境特性,该研究采取现场测试的方法,选取河南地区某规模化母猪场妊娠舍为试验猪舍,对该猪舍夏季和冬季舍内热环境和空气质量环境进行测试和分析,结果表明：1）改进湿帘降温系统夏季对新风的平均降温功率增加了?84.4 kW,提高了25%的降温效果;冬季对新风的平均加热功率增加了121.6 kW且舍内无需供暖,87%以上的节能效果发生在地下风道前半程。2）试验猪舍舍内温湿度、风速分布均匀,且舍内温度波动低于3.7 ℃;综合猪舍母猪体感有效温度和呼吸频率等应激程度指标,母猪冬季处于舒适状态,夏季有轻度热应激状态现象。3）夏季和冬季舍内氨气（NH3）、二氧化碳（CO2）、和粉尘（PM2.5和PM10）的质量浓度分布均匀,且均小于国家标准规定的妊娠舍空气污染物浓度极限水平。综上所述,改进湿帘降温系统不仅降低妊娠母猪舍热环境调控的能耗并维持舍内空气质量环境良好,对建立环境友好型规模化母猪场具有积极意义。 相似文献
6.
负压湿帘风机降温被广泛应用于温室生产中,但存在降温均匀性差、限制温室长度及对温室密闭性要求高等不足。为克服负压湿帘风机降温的局限性,提高日光温室降温能力,该研究设计了日光温室正压湿帘冷风降温系统,其气流组织方式为湿冷空气从南屋面底部进入日光温室,热空气由顶开窗排出室外。在北京地区无作物的日光温室对系统夏季降温增湿效果及性能进行试验,试验结果表明:在典型夏季高温白天,正压湿帘冷风降温系统配合遮阳网可将日光温室试验区内平均气温控制在30.7～33.4℃,比采用自然通风配合遮阳网的对照区低5.4～11.1℃,比室外低2.4～5.4℃,降温效果良好;夜间系统对温室降温幅度减小。该系统可有效缓解低湿胁迫,日光温室试验区空气平均相对湿度为49.8%～62.3%,比对照区及室外分别高13.6%～21.2%和13.6%～24.6%。室内风速0.35～1 m/s,气流分布差异性较小。试验条件下,正压湿帘冷风降温系统的平均降温效率为91%,比传统的负压湿帘风机高10个百分点以上;实际平均耗水量为0.035～0.079 g/(m~2·s),且耗水量与室外空气水蒸气饱和压差(VPD,vapor pressure deficit)呈正相关(P0.01,r=0.64)。同时,研究构建了日光温室冷负荷计算模型及湿帘冷风降温设备合理选型方法,其中冷负荷模型是降温设备选型的基础,普遍适用于各种日光温室降温方法的研究。计算得到日光温室夏季降温冷负荷为299.1W/m~2,应安装的正压湿帘冷风降温系统最大比通风量为0.067 m/s。该研究为日光温室正压湿帘冷风降温方法的工程应用提供了技术参考,为日光温室安全越夏生产环境控制提供了理论基础。 相似文献
7.
南方夏季肉牛舍湿帘风机负压通风系统降温效果 总被引：3，自引：1，他引：2
为改善南方夏季肉牛舍环境条件,该文对湿帘风机负压通风系统在肉牛舍的降温效果进行了探究。试验以栓系饲养西门塔尔公牛为试验对象,对环境、肉牛生理及增重情况进行测定。结果表明：降温后,试验舍平均温度降低3.2 ℃（P<0.01）,相对湿度增加21.3%（P<0.01）,肉牛附近风速增加0.30 m/s（P<0.01）,肉牛体感温度降低1.8 ℃（P<0.01）;试验牛呼吸频率平均降低13次/min（P<0.01）,皮温降低0.92 ℃（P<0.01）,平均日增质量提高0.13 kg/d（P>0.05）。由此可知,在肉牛舍中采用湿帘风机负压通风系统进行降温,能够有效改善舍内热环境,有助于缓解肉牛热应激,具有技术可行性。 相似文献
8.
冷风机-风管对南方开放式牛舍的降温效果 总被引：3，自引：7，他引：3
为改善南方夏季开放式肉牛舍环境条件,该文设计湿帘冷风机-纤维风管系统,采用风管定点送风、孔口射流高速出风的模式,将冷风均匀送至肉牛活动区域进行局部降温。该研究以栓系饲养西门塔尔牛为试验对象,对环境、肉牛生理及增质量进行测定。结果表明:测定期间,在肉牛站立(1.3 m高度)和躺卧背部高度(0.7 m高度),与对照舍相比,处理舍的平均温度分别降低2.0和1.8℃,平均相对湿度皆增加10%,平均风速分别增加0.69和0.47 m/s(P0.01);试验舍内氨气和二氧化碳平均质量浓度比对照舍分别降低0.17和81 mg/m3,热负荷指数(heat load index,HLI)均值降低2.84(P0.01);试验牛的呼吸频率降低22次/min、直肠温度降低0.35℃、皮温降低1.04℃,差异均极显著(P0.01)。在整个试验期间,处理舍肉牛未出现患病情况,日增质量为0.92 kg/d;对照舍肉牛患病率高达47%,日增质量为0.54 kg/d,差异极显著(P0.01)。该研究表明在开放式牛舍中进行湿帘冷风机-纤维风管局部降温,有助于缓解肉牛热应激,应用于南方夏季高温高湿天气下技术和经济可行。 相似文献
9.
本文通过对北京市种鸡场平养密闭舍1986年夏至1987年春环境因素观测分析,指出该舍内气流速度、气流方向、光照时间及光照度等基本符合鸡的生理要求;但夏季舍内呈现高温、高湿,冬季呈现低温、高湿有待改进。经研究提出措施是:夏季可采用湿帘降温,冬季可根据温、湿度、氨气浓度综合控制风机运转等。 相似文献
10.
夏季肉牛舍湿帘风机纵向通风系统的环境CFD模拟 总被引：3，自引：2，他引：1
为了研究湿帘风机纵向通风系统应用于肉牛舍的夏季降温效果,该试验在现场环境指标实测的基础上,采用计算流体力学(computational fluid dynamics,CFD)的方法对湿帘风机纵向通风肉牛舍的气流场与温度场进行模拟,并对系统进行改进与优化.模拟时将牛只按与实物原型等比例引入到模型中,结果表明:舍内温度分布均匀,但受牛体挡风的影响,气流分布不均,高风速区主要集中在屋顶及饲喂走道,可达0.9～1.2 m/s;牛活动区域风速较小,均小于0.6 m/s,不能满足饲养标准.在75个风速测定点剔除异常值后,气流场的相对误差范围为0.16％～94.41％,平均相对误差为34.53％,45个温度测点的相对误差范围为0.09％～10.74％,平均相对误差4.71％.通过温度场吻合性结果确定模拟与实测有较好的吻合度.在不改变牛舍围护结构及舍内构造的前提下,对牛舍进行优化,舍内安装导流板,使得温度与气流场的分布均匀性显著提高,降温效果更为显著.该研究可为湿帘风机牛舍的优化设计和环境调控提供参考. 相似文献
11.
【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。 相似文献
12.
Kyle Devey Michael Mucalo Gordon Rajendram Joseph Lane 《Communications in Soil Science and Plant Analysis》2015,46(4):72-80
Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing. 相似文献
13.
《中国生态农业学报》2014,(8)
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology, 相似文献
14.
Aleš Lebeda Ivana Doležalová Eva Křístková Barbora Mieslerová 《Genetic Resources and Crop Evolution》2001,48(2):153-164
Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions. 相似文献
15.
M.A. Callaham Jr. J.M. BlairT.C. Todd D.J. KitchenM.R. Whiles 《Soil biology & biochemistry》2003,35(8):1079-1093
The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils. 相似文献
16.
Thomas Larsen Jesper Luxhøi Jakob Magid Lars Stoumann Jensen Paul Henning Krogh 《Biology and Fertility of Soils》2007,44(1):59-68
We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization
and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition
with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the
decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots
with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass,
soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration,
N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially
(<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation
in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils,
indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but
the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation
for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community
performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea. 相似文献
17.
《中国生态农业学报》2014,(7)
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology, 相似文献
18.
《中国生态农业学报》2014,(6)
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology, 相似文献
19.
Grete Skrede Berit Karoline Martinsen Anne-Berit Wold Stein-Erik Birkeland Kjersti Aaby 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):193-208
Abstract A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species. 相似文献
20.
《Communications in Soil Science and Plant Analysis》2012,43(7):865-877
Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L?1 nitric acid (HNO3) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L?1 ammonium acetate (NH4OAc) and 1.0 mol L?1 HNO3 extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils. 相似文献