蛋鸡舍热湿环境参数全年逐时动态预测模型

准确预测蛋鸡舍内温度和相对湿度参数动态变化是精准调控舍内热湿环境的重要条件。然而,现有预测模型通常未能考虑湿帘降温效率的变化及其对舍内热湿环境的影响。针对此问题,该研究通过分析湿帘降温效率变化规律和舍内热、湿平衡关系,构建了蛋鸡舍内温、湿度全年逐时动态变化预测模型,并进行了现场验证、案例展示和讨论分析。结果表明:1)蛋鸡舍内温、湿度模拟值与实测值变化趋势一致,舍内温度的平均预测误差为0.67℃,舍内相对湿度的平均预测误差为3.1%;2)因围护结构热惰性而引起蛋鸡舍内温度的延迟(夏季无延迟,冬季1 h)和衰减(夏季0.3℃,冬季1.02℃)均较小;3)若不考虑湿帘降温效率的动态变化,如设为80%定值时,模拟的温度误差为1.4℃,相对湿度误差为5.4%,模型预测精准度降低。该研究可为蛋鸡舍建筑设计与热湿环境调控提供理论指导,以提高蛋鸡生产性能。     

夏季鸡舍屋顶隔热改善舍内热环境及蛋鸡生产性能

鸡舍屋顶夏季所接收辐射热最多,屋顶内表面与舍内空气对流换热作用较强,舍内垂直温差加剧,造成局部热应激影响蛋鸡生产性能。为探究屋顶隔热对蛋鸡舍内热环境及蛋鸡生产性能的影响,该文对比研究试验舍(100 mm保温玻璃棉毡彩钢板屋顶)与对照舍(200 mm加气混凝土屋顶)2种不同材料屋顶对鸡舍内环境及生产性能的影响,并讨论鸡舍屋顶成本与养鸡经济效益的关系。结果表明:1)试验舍内温湿度波动比对照舍内小,试验舍内平均温度比对照鸡舍低2.3℃,对照舍内温度空间上呈垂直分布且温差大于3℃,由地面向屋顶逐渐升高且距离地面3.2 m高度水平面温度与0.8、1.6、2.4 m高度水平面温度差异极显著(P0.01);2)试验舍内热应激程度低于对照舍,对照舍内温湿指标正常水平比试验舍内低15.7%,轻度热应激程度高12.1%,中度热应激程度高1.7%,高度热应激程度高0.9%。对照舍内3.2 m平面上蛋鸡受到不同程度的热应激,高度热应激占2.5%;3)试验舍蛋鸡产蛋率比对照鸡舍高1.5%,平均蛋质量高1.9 g。对照舍3.2 m平面上蛋鸡产蛋率与距离地面0.8、1.6、2.4 m平面蛋鸡产蛋率差异极显著(P0.01),周死淘率差异显著(P0.05);试验舍和对照舍0.8 m平面上蛋鸡平均蛋质量最高,对照舍底层0.8 m平面上蛋鸡平均蛋质量与距离地面1.6、2.4、3.2 m平面蛋鸡的平均蛋质量差异极显著(P0.01),但破蛋率之间差异不显著(P0.05);4)对照舍屋顶的冷负荷峰值是试验舍屋顶冷负荷峰值的2.1倍,对照舍屋顶内表面温度比试验舍高3℃。试验鸡舍采用隔热屋顶1~1.5 a可收回投入成本,维持舍内热环境以提高蛋鸡养殖户的收入。该研究可为集约化密集型饲养模式下蛋鸡舍的环境调控及节能措施提供参考。     

夏季鸡舍纵向通风系统的应用与研究

本文介绍了在我国各地不同类型鸡舍内纵向通风系统的应用情况;分析了湿垫蒸发降温对我国各地气候的适应性。实际应用结果表明:纵向通风结合湿垫降温系统可将我国各地的不同类型鸡舍的夏季气温基本控制在28～30℃以下,舍内气流速度可达1.0～2.0m/s,气流分布均匀,可为鸡群提供100％的新鲜空气;一般,夏季蛋鸡和种鸡的产蛋率可提高5％以上,饲养密度可提高10％～20％,制止了高温应激死鸡;且较传统的横向通风节约电能和运行费用达40％以上。     

规模化猪场妊娠母猪舍改进湿帘降温系统的环境特性

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。     

不同通风形式滴水降温系统的试验研究

为缓解母猪的热应激,在我国南方高温高湿地区对3种不同通风形式的滴水降温系统进行了比较试验,这3种通风形式分别为：1）纵向通风加局部正压送风;2）纵向通风;3）循环风机,使用纵向通风和循环风机的舍内风速分别为0.51 m/s和0.40 m/s。将母猪的体温和呼吸频率作为降温效果的评价指标,结果表明：纵向通风与滴水相结合的降温系统能有效缓解母猪的热应激,在舍内平均温湿度分别为31.5 ℃和82.5%时,母猪的平均体温和呼吸频率分别为38.99 ℃和45.4次/min,风机运行的耗电量为2.0 kW·h;滴水系     

我国南方地区蛋鸡场环境控制研究

主要通过对蛋鸡舍改造和鸡粪污水无害化处理控制鸡场环境。蛋鸡舍安装自行研制的风机和喷头进行纵向通风和喷雾，在夏季高温季节可使蛋鸡舍内温度下降3～5℃；鸡粪通过发酵烘干成为商品肥料，污水通过处理达标排放，有良好的社会和经济效益。     

南方夏季肉牛舍湿帘风机负压通风系统降温效果

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。     

鸡舍湿垫—风机降温系统的应用与设计

鸡舍内温度和湿度的控制是非常重要的.本文介绍了湿垫—风机降温系统在鸡舍里应用情况和设计方法.实际应用表明,即使在南方夏季高温而昼夜温差较小的地区,在鸡舍内应用湿垫—风机降温也是非常有效的.它使鸡舍内平均温度控制在30℃左右,平均相对湿度约75—80%。在解除了舍内高温喊协后,这种水平的相对湿度对鸡体也不会产生不良的后果。本文介绍的鸡舍湿垫—风机降温系统的实用设计方法,概念明确、计算简便,鸡舍内采用纵向通风型式,可以应用少量大直陉风机,能够节省大量的夏季通风动力消耗,     

不同气候区猪舍最大通风量确定及湿帘降温系统应用效果

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。     

蛋鸡舍冬季CO2浓度控制标准与最小通风量确定

中国现行的蛋鸡舍内CO_2浓度控制的农业行业标准为1 500 mg/m~3,主要适用于传统的刮板式清粪鸡舍。目前新建、改建鸡舍都采用传送带清粪方式,鸡舍内的相对湿度和氨气等有害气体浓度均明显减少,其冬季最小通风量和舍内CO_2浓度参数标准均有待重新研究。该文通过总结分析国内外相关学者对不同清粪方式蛋鸡舍内NH_3、CO_2浓度的测试数据,提出传送带清粪蛋鸡舍内CO_2浓度取值建议,并根据CO_2浓度平衡原理,提出该类蛋鸡舍冬季最小通风量的取值建议。结果表明:传送带清粪蛋鸡舍内CO_2浓度参数控制标准建议可取5 000 mg/m~3;蛋鸡舍冬季连续通风最小通风量为0.40~0.50 m~3/(h·kg)。该研究为中国新建、改建传送带清粪模式蛋鸡舍CO_2浓度参数标准的取值以及调控蛋鸡舍冬季通风与保温矛盾等问题提供了参考依据。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【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。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

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.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

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,     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

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.     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

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.     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

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.     

Electron donor and pH relationships for biologically enhanced dissolution of chlorinated solvent DNAPL in groundwater

Biologically enhanced dissolution offers a method to speed removal of chlorinated solvent dense non-aqueous-phase liquid (DNAPL) sources such as tetrachloroethene (PCE) and trichoroethene (TCE) from aquifers. Bioremediation is accomplished by adding an electron donor to the source zone where fermentation to intermediates leading to acetic acid and hydrogen results. The hydrogen and possibly acetic acid are used by dehalogenating bacteria to convert PCE and TCE to ethene and hydrochloric acid. Reductive dehalogenation is thus an acid forming process, and sufficient alkalinity must be present to maintain a near neutral pH. The bicarbonate alkalinity required to maintain pH above 6.5 is a function of the electron donor: 800 mg/L of bicarbonate alkalinity is sufficient to achieve about 1.2 mM TCE dechlorination with glucose, 1.7 mM with lactate, and a much higher 3.3 mM with formate. Laboratory studies indicate that in mixed culture, formate can be used as an electron donor for complete conversion to ethene, contrary to pure cultures studies indicating it cannot. Various strategies can be used to add electron donor to an aquifer for DNAPL dehalogenation while minimizing pH problems and excessive electron donor usage, including use of injection-extraction wells, dual recirculation wells, and nested injection-extraction wells.     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

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.     

Increase in auxiliary photoprotective photosynthetic pigments in wheat seedlings induced by Azospirillum brasilense

Inoculation of wheat seedlings with the plant growth-promoting bacterium Azospirillum brasilense Cd was immobilized in alginate microbeads and, without applying any stress, significantly increased the quantity of several photosynthetic pigments, such as chlorophyll a, chlorophyll b, and the auxiliary photoprotective pigments violaxanthin, zeaxanthin, antheroxanthin, lutein, neoxanthin, and β-carotene. This resulted in greener plants with no apparent visible stress. After monitoring the quantity of photosynthetic pigments for 4 weeks, we observed that inoculated plants had higher quantities of pigments in shoot and stem. The greatest difference in the quantity of all pigments between inoculated and noninoculated plants occurred in the first week of growth. Regardless of treatment, the quantity of pigments in stems was three to four times less than the quantity of these pigments in shoots. Application of Azospirillum, either as liquid inoculant or as alginate microbeads, did not alter the positive effect of the bacteria on pigment production or the positive response of the plants towards A. brasilense Cd inoculation.     

In-situ enrichment and analysis of atrazine-degrading microbial communities using atrazine-containing porous beads

We examined the community composition of microbes that colonized atrazine-containing beads buried in agricultural soils that differed in atrazine treatment history. Bacterial abundance was 5-40-fold greater in atrazine-fortified beads. In beads containing 20 mg atrazine kg⁻¹ buried in soil with a history of atrazine application (conditioned soil), the abundance of Actinobacteria increased approximately 80-fold whereas in control soil, Actinobacteria were enriched only 10-fold and the gamma-Proteobacteria and Planctomycetes increased by 60- and 25-fold, respectively. The gamma-Proteobacteria were enriched by 120- and 230-fold in beads containing 200 mg atrazine kg⁻¹ in conditioned and control soil, respectively. The results demonstrate that BioSep^® beads are a suitable matrix for recruiting a diverse subset of the bacterial community involved in atrazine degradation.