蚕豆赤斑病流行趋势预报的模糊识别模式研究

本文应用频率圆盘法(模式Ⅰ)、样本圆盘法(模式Ⅱ)和模糊点聚法(模式Ⅲ(1)(2)),对射阳县蚕豆赤斑病流行趋势进行了模糊识别预报。结果表明:模式Ⅰ和模式Ⅲ(1)的符合率达100%,模式Ⅱ和模式Ⅲ(2)的符合率仅为50％。应用时,可首先考虑模式Ⅰ、Ⅲ(1)及其结果。

用逐步回归分析模型预测水稻稻瘟病流行趋势

水稻稻瘟病是我国水稻栽培中的重要病害,对该病害防治的关键是要做好预测工作。应用逐步回归分析,对影响水稻稻瘟病流行趋势的多种预报因子进行优选,择出优势因子并组建水稻稻瘟病流行趋势的逐步回归分析模型。验证结果表明:历史符合率达97.4%,3年预测结果的平均符合率也达到85.3%,符合率较高,为该病害的预测及其防治提供了依据。

应用判别分析模型预测小麦白粉病流行趋势

丁世飞．应用判别分析模型预测小麦白粉病流行趋势．本文首先应用逐步回归分析，对影响小麦白粉病流行趋势的各种预报因子进行了优选，择出优势因子；其次应用多级判别分析技术，组建了小麦白粉病流行趋势的３个级别的判别分析模型。验证结果表明：历史拟合率达９２．３１％，两年（１９８７、１９８８）试报。

稻瘤矮病介体叶蝉带毒率与田间发病关系研究

水稻瘤矮病自在国内被发现和报道以来已发生多次较大的流行,近年来都是中等偏重发病,并有不断蔓延趋势。利用制备的鼠腹水抗体和已建立的聚乙烯吡喏烷酮酶联免疫吸附法(PVP-EL ISA法),通过6次检测早、晚季稻秧苗田和早季稻收割前后的大田介体电光叶蝉带毒率,初步探讨了介体带毒率与本田实际发病间的关系,建立了病害预报模型,以检测介体叶蝉带毒率来预报晚季本田发病情况。该模型的建立,为有效喷药防病、减少喷药次数和避免盲目喷药奠定基础。经数年的跟踪实施,证明是可行的。

Regional epidemic laws of poplar Ice Nucleation Active bacterial canker

Through the methods of correlation analysis and main factor analysis, the relationship between the poplar INA bacte-rial canker and circumstances was analyzed and 9 main factors for affecting the disease were selected. Based on the compre-hensive analysis of main factors and induced factors, the standard for risk grades of this disease was promoted and northeast region of China was divided into 4 districts with different risk grades: seriously occurring district, commonly occurring district, occasionally occurring district, and un-occurring district. Nonlinear regression analysis for six model curves showed that the Richard growth model was suitable for describing the temporal dynamics of poplar INA bacterial canker. By stepwise variable selection method, the multi-variable linear regression forecasting equation was set up to predict the next year抯 disease index, and the GM (1,1) model was also set up by grey method to submit middle or long period forecast.