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101.
近年来,青藏高原迁徙的野生鸟类不断发生高致病禽流感疫病,给生态安全和人们的健康带来了极大的威胁。如何面对和做好野生鸟类的疫源疫病监测与防控,本文通过青海省发生和开展的防控工作情况,就面临和亟待解决的问题,提出对策建议。 相似文献
102.
Analyses of the impact of changes in atmospheric deposition and climate on forest growth in European monitoring plots: A stand growth approach 总被引:1,自引:0,他引:1
Svein Solberg Matthias Dobbertin Gert Jan Reinds Holger Lange Kjell Andreassen Paloma Garcia Fernandez Anders Hildingsson Wim de Vries 《Forest Ecology and Management》2009
During the last 15 years a number of studies have shown increasing forest growth in central Europe, rather than a decline as was expected due to negative effects of air pollution. We have here used data from intensive monitoring plots spread over Europe for a five year period in order to examine the influence of environmental factors on forest growth. Evaluations focussed on the influence of nitrogen, sulphur and acid deposition, temperatures, precipitation and on a drought index calculated as deviation from the long-term mean. The study included the main tree species Norway spruce, Scots pine, common beech as well as European and sessile oak and was based on data from 363 plots. As many other factors besides nitrogen and temperature influence tree growth, expected stem volume increments were modelled using site productivity, stand age and a stand density index. Relative volume increment was then calculated as actual increment in % of expected increment. The site productivity, assumed to be given by site conditions and past environmental conditions, was either taken from expert estimates or computed from site index curves from northern, central and southern Europe. The model explained between 18% and 39% of the variance with site productivity being positively related and age negatively related to actual increment. The various models and statistical approaches were fairly consistent, and indicated a fertilizing effect of nitrogen deposition, with slightly above one percent increase in volume increment per kg of nitrogen deposition per ha and year. This was most clear for spruce and pine, and most pronounced for plots having soil C/N ratios above 25. Also, we found a positive relationship between relative increment and summer temperature, i.e. May–August mean temperature deviation from the 1961–1990 means. The cause–effect relationship here is, however, less certain. Other influences were uncertain. Possibly, sulphur and acid deposition have effects on growth, but these effects are obscured by, and outweighed by the positive effect of nitrogen deposition, because of collinearity between these variables. Drought effects were uncertain also, and one reason for this might be large uncertainties in the precipitation data: precipitation measured on some 50% of the plots correlated poorly with the precipitation data obtained from Europe-wide databases. The major finding of this study was a positive relationship between higher than normal volume increment on one hand and nitrogen deposition on the other hand. 相似文献
103.
Y. Sun L. Li P. Schulze Lammers Q. Zeng J. Lin H. Schumann 《Computers and Electronics in Agriculture》2009,69(1):19-23
In various agricultural activities, such as irrigation scheduling, tillage operation and nutrient management, soil water content is regarded as an essential parameter. For the demand of monitoring soil water dynamics at field scale, this study presents a solar-powered wireless cell that contained a water content sensor, two temperature sensors, an optical sensor, a communication module and a data-logger. To evaluate its feasibility in the field, three cells were independently installed in a bare plot, a maize plot and a sugarbeet plot in the summer of 2008. By a heavy rain event (20 mm, 6 h) during the experimental period, different responses of soil water content sensors were dynamically recorded and then analyzed under each canopy condition. In addition, to explore the possibility of reducing the dimensions of the cell under the condition of sufficient energy supply, various sizes of the solar panel were tested. The experimental results showed that the cell is promising to become a node of wireless network in the field. 相似文献
104.
高速公路监控系统正日益成为高速公路日常运营管理的一个重要手段,发挥着重要的作用。其主要是通过道路监控摄像机作为视频图像采集系统进行监控的。该文在分析高速公路监控需求的基础上,阐述了对高速公路监控摄像机的性能要求,以及进行监控摄像机的选择时需要考虑的因素。 相似文献
105.
汽车回收行业中再利用零配件智能电子商务系统 总被引:1,自引:0,他引:1
彭鹏 《拖拉机与农用运输车》2012,39(2):68-71
介绍了汽车回收再利用零配件现状,首次提出了再利用零配件智能电子商务(EC)系统整体设计方案。着重研究了系统四个关键技术,制定了再利用零配件20位条码编码规范,实现与系统的无缝自动连接;在电子商务交易中利用C#的管道技术对再利用汽车回用件流向采用流水线作业算法,自动转化流程;采用多值影响评估算法对再利用零配件估价;设计了再利用汽车零部件的监控体系。系统能有效地提高工作效率,规范汽车再利用配件交易,具有广阔的应用前景。 相似文献
106.
2009~2010年婺源县主栽早稻品种稻瘟病的抗性监测 总被引:2,自引:1,他引:1
婺源县为江西省稻瘟病的常发区和重发区。2009~2010年分3批播种(间隔期5 d),评估婺源县9个主栽早稻品种对水稻稻瘟病的抗性。结果表明,两年中,株两优02和株两优09对叶瘟的抗性均保持中抗,陆两优996、淦鑫203、T优898和春光1号为中感,抗性改变的品种有3个,其中金优463由中抗变为高感,金优458和先农37号均由感病变为高感。两年中,株两优02、淦鑫203和株两优09对穗瘟的抗性均保持中抗以上,陆两优996、T优898为中感,春光1号为高感,抗性改变的品种有3个,其中金优463由中感变为高感,金优458和先农37号均由感病变为高感。在以上9个品种中,只有株两优09和株两优02对叶瘟和穗瘟的抗性两年中均保持在中抗以上。 相似文献
107.
高-中-低精度遥感的大区域高精度耕地面积估测分析 总被引:2,自引:0,他引:2
介绍了国内外的遥感抽样监测方法,分析了遥感抽样监测在大范围耕地监测中的优越性与局限性,最后就大范围高精度的耕地监测提出了采用高-中-低分辨率遥感影像逐步抽样的解决方案. 相似文献
108.
对京承农业走廊区域内空间信息资源管理、农产品供求、观光农业、农业技术推广、土地利用监测和农业生态评价等方面的问题进行深入分析研究,运用网络地理信息技术,建立基于WebGIS的都市型现代农业走廊网络服务系统。系统包括走廊管理、园区动态、技术示范、供求信息和观光农业等模块,采用土地利用动态变化、生态服务价值量和景观生态丰度等模型,对京承农业走廊内的土地利用变化、景观和生态效益进行分析评价,解决了上述在农业走廊区域内农业发展转变过程中所要面临的问题;系统化地构建了为农民、消费者、经销商和管理部门等提供信息、技术和服务的网络平台,以提高都市型现代农业的科学化管理、规划和实施水平。 相似文献
109.
110.
A comparison of monitoring systems used for Ceratitis species (Diptera: Tephritidae) in South Africa
For 16 years a bucket-type trap known as the Sensus fruit fly trap has been used to monitor three fruit fly pest species Ceratitis capitata, Ceratitis rosa and Ceratitis cosyra in South African fruit industries. The relative efficiencies of lures sold for monitoring fruit flies with the Sensus trap in South Africa were determined in field experiments where laboratory-reared C. capitata, C. rosa and C. cosyra were released in a mango orchard within a few metres of Sensus traps containing either Capilure (trimedlure or tert-butyl 4 (or 5) -chloro-2-methylcyclohexane carboxylate), Ceratitislure (protein hydrolysate plus β-caryophyllene) or Questlure (protein hydrolysate plus plant extracts). When using 12-day-old flies, Capilure caught 3 times more C. capitata males than C. rosa males and this difference was more extreme when 3-day-old flies were released. Ceratitislure caught significantly more 12-day-old C. cosyra males than 12-day-old C. capitata males, but the difference was reversed when 3-day-old flies were compared. Questlure showed the least differences between species and age but recovered the lowest proportion of released species. Further comparisons were conducted in an orchard with wild flies using other known attractants in larger yellow Probodelt bucket traps. Capilure caught more male C. capitata than BioLure Fruit Fly 3-component, but BioLure 2-component (trimethylamine and ammonium acetate) was more effective than Questlure for C. capitata females. The 3-component lure was also more effective than both Capilure and Questlure for male and female C. rosa, respectively. Ceratitislure was the most effective lure for male C. cosyra flies and BioLure 3-component was more effective than Ceratitislure and Questlure for female C. cosyra flies. The intervention threshold of 4 flies/trap/week previously used in citrus with Capilure for C. rosa was lowered to 2 C. rosa/trap/week when using the Sensus trap due to the lower sensitivity of this trap-lure combination found for C. rosa in this study. The 3-component lure, or the 2-component combination of trimethylamine and ammonium acetate in a ratio of 1:8 in the Sensus trap capsule, would be more effective for both sexes of all three Ceratitis species than the Questlure that is currently being used. 相似文献