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根据河南、河北两省多年多点对玉米小斑病流行进程的观察记载,共积累20个年次的病情系统调查资料,结合相应的气象数据,按照本病的流行规律,设计8个供选因子,用北京大学DJS-18型电子计算机进行逐步回归运算,分别推导出从7月中旬至8月中旬的30天中期预测式和从7月中旬至9月中旬的60天长期预测式。所谓测报时间范围内相应时期的气象因素,在中期预报中为7月份的总雨量、总雨日、日平均温度等,在长期预报中为7、8两个月的上述气象因素。两个预报式的确定系数分别为0.8125和0.6843,经用建立模型以外的多个实际病情对所得方程式进行检验,证明预测式有较高的可靠度。长期预报式可用做流行强度的趋势性预报,中期预报式可供确定防治适期的参考。
According to the observation and record of multi-spot epidemic process of maize small spot disease in Henan and Hebei provinces for many years, a total of 20 systematic investigation data of disease were accumulated and combined with corresponding meteorological data to design 8 options for selection according to the epidemic law of this disease Factor, using the step-by-step regression of DJS-18 electronic computer at Peking University to derive the 30-day mid-term forecast from mid-July to mid-August and the 60-day long-term forecast from mid-July to mid-September. The so-called meteorological factors of the corresponding period in the reporting time range are the above-mentioned meteorological factors in July, August and August in the long-term forecast for the medium-term forecast for total rainfall in July, total rainfall days and daily average temperature. The two forecasting coefficients are 0.8125 and 0.6843, respectively. After testing the obtained equations with several actual conditions other than the established model, the predictive formula has higher reliability. Long-term forecasting can be used as a trend forecast of epidemic intensity, and mid-term forecasting can be used as reference for determining the appropriate period of control.