基于集合卡尔曼滤波的PyWOFOST模型在东北玉米估产中的适用性验证

以叶面积指数(LAI)为结合点,引入基于集合卡尔曼滤波(Ensemble Kalman Filter,EnKF)的作物模型-遥感信息耦合模型PyWOFOST,利用气象数据、农业气象记录观测表数据及MODIS LAI数据检验PyWOFOST模型在东北玉米种植区的适用性,并选取在研究区内均匀分布、覆盖所有玉米品种且具有有效MODIS LAI数据的16个玉米农气站点,模拟该模型在不同的TSUM1(出苗-开花期积温)不确定性水平下各站点的玉米产量及LAI。结果表明,与WOFOST模型相比,PyWOFOST模型对LAI和产量的模拟能力都有极大提高。当TSUM1的不确定性为0、10、20、30℃时,PyWOFOST模拟的产量平均误差分别为10.32%、9.25%、7.31%和8.49%,均较未同化LAI观测数据的WOFOST模拟的产量平均误差(10.55%)低;同化后模拟LAI与同化前模拟LAI相比,其轨迹更接近实测值,更符合玉米的生长发育趋势,表明基于EnKF的PyWOFOST模型在东北玉米种植区有较好的适用性。     

Hierarchical classification of environmental factors and agricultural practices affecting soil fauna under cropping systems using Bt maize

The population dynamics of soil organisms under agricultural field conditions are influenced by many factors, such as pedology and climate, but also farming practices such as crop type, tillage and the use of pesticides. To assess the real effects of farming practices on soil organisms it is necessary to rank the influence of all of these parameters. Bt maize (Zea mays L.), as a crop recently introduced into farming practices, is a genetically modified maize with the Cry1Ab gene which produces a protein toxic to specific lepidopteran insect pests. To assess the effects of Bt maize on non-target soil organisms, we conducted research at a field site in Foulum (Denmark) with a loamy sand soil containing 6.4% organic matter. The study focused on populations of springtails (Collembola) and earthworms (Oligochaeta) from samples taken at the beginning and at the end of the maize crop-growing season during 2 consecutive years. Farming practices, soil parameters, the biological structure of soil communities, and the type and age of the crop at the time of sampling, were used as attributes to predict the total abundance of springtails and biomass of earthworms in general and the abundance or biomass for specific functional groups (epigeic, endogeic and anecic groups for earthworms, and eu-, eu to hemi-, hemi-, hemi to epi- and epiedaphic groups for Collembola). Predictive models were built with data mining tools, such as regression trees that predict the value of a dependent variable from a set of independent variables. Regression trees were constructed with the data mining system M5′. The models were evaluated by qualitative and quantitative measures of performance and two models were selected for further interpretation: anecic worms and hemi-epiedaphic Collembola. The anecic worms (r²=0.83) showed preferences for less clay and more silt soil with medium pH but were not influenced directly by farming practices. The biomass of earthworms was greater in early autumn than in spring or late autumn. Biomass of hemi-epiedaphic Collembola (r²=0.59) increased at the end of the maize growing season, while higher organic matter content and pH tended to increase their biomass in spring. Greater abundance of Collembola was also noted in early autumn if the crop was non-Bt maize. The models assessed by this research did not find any effects of the Bt maize cropping system on functional groups of soil fauna.     

基于ARCGIS的土壤空间数据校正辅助软件的设计与实现

本文针对目前土壤普查项目中土壤空间数据校正难问题,运用ARCGIS中的VBA语言,设计了数据校正辅助系统,系统除了能自动将测土数据导入成矢量文件外,还结合1：5万县级乡镇行政图标出所有空间位置有问题的观测点,达到数据校正的目的。该系统是在ARCGIS中实现的,操作简单,扩展性能强,不需要太多的GIS专业知识,是农业技术人员土壤普查数据研究中进行空间数据校正的好帮手。     

National Evaluation of User Profiles in Aquaculture

One problem with information delivery to a specific segment of the agricultural community is identifying the characteristics and needs of the end-user. Such a profile could be used for evaluation of the products or services provided. The Aquaculture Information Center of the National Agricultural Library was able to construct to such a profile based on historical data as well as current assessments from several United States aquaculture information groups. Analysis of this data provided specific and general direction for future products and services within the aquaculture information community. Findings also highlighted the important need for further tracking of such data, emphasis on continued networking among information groups, and creation of formal guidelines for aquaculture information access for the end-user.     

利用XMLSPY实现XML文档与关系型数据库的转换

XML是目前广泛采用的WEB信息交换、存储、处理的技术之一,渐已成为数据表示的标准格式.本文在分析XML文档和数据库各自优势的基础上,对数据库与XML文档转换的两种形式进行了探讨,介绍了XML专业开发工具XMLSPY的主要功能,以ACCESS数据库为例,实现了数据库与XML文档的互相转换.     

基于贝叶斯分类的农作物产品质量挖掘研究

采用贝叶斯算法的基本原理,并结合农作物生长环境数据的特点,分析和预测了农作物的产品质量。采用随机选取的样本组进行试验预测,预测准确率高,表明该算法是有效的。     

基于文献分析的国内图书馆大数据应用研究述评

大数据在图书馆的应用将是未来图书馆发展的必经之路,关于图书馆应用大数据技术的研究已经展开,现就目前已经出版的研究论文在出版来源、出版年代、引文、内容等方面作出分析,并提出已有研究的不足与对今后的前景展望,为后续深入研究提供参考借鉴。     

异构数据库系统数据共享及实现

本文系统地介绍了异构数据库的特点,详细分析了实现异构数据库共享的三种方法(数据库转换、基于中间件和数据库网关)的优缺点,并通过两个例子阐述了在PowerBuilder环境下基于数据管道技术和ODBC中间件技术来实现数据共享的方法。     

数据挖掘在农业领域中的应用研究

数据挖掘作为一项极具应用前景的技术,在处理农业领域积累的大量农业数据信息中起着非常重要作用.本文首先探讨了数据挖掘的一般过程和系统典型体系结构,然后总结了数据挖掘在农业领域各个方向的应用现状,最后提出了数据挖掘技术在农业领域应用中存在的问题,并说明未来的研究趋势和应用前景.     

地面数据传输及质量控制实例分析

详细阐述地面测报软件主辅通道上传数据时间设置以及数据上传不成功的处理方法。自动站采集气温、本站气压、相对湿度、风向、风速以及雨量正点数据如果判断是错误数据,应按先分钟数据替代,然后人工数据替代,最后内插的原则修改,保存形成正确上传文件;台站预审人员应正确进行月报表A文件一般性备注和历史沿革备注。