论文部分内容阅读
通过对历史资料的搜集、整理和分析,对鄂尔多斯高原东南部榆林地区清代(1644-1911年)蝗灾的变化规律、蝗灾等级、发生条件及其预测进行了研究。结果表明,在清代的268a里,鄂尔多斯高原东南部地区共发生蝗灾16次,平均每16.8 a发生1次。该区清代中期是蝗灾较少发生期,早期和晚期为蝗灾较多发生期。在晚期阶段1850-1879年间的30a里,平均4.3a发生1次,且蝗灾规模大而严重,为蝗灾大爆发期。该区的蝗灾主要是由当地生长的蝗虫造成的,少数规模较大的蝗灾是省外蝗虫迁移至该区造成的。研究地区夏蝗和秋蝗发生较多,并且夏蝗发生次数略高于秋蝗。该区清代发生最多的是中度蝗灾,其次为轻度蝗灾,重度蝗灾发生最少。降水量与蝗灾发生频次的相关系数较气温的大,降水偏少年易于发生蝗灾,轻度和中度旱灾是蝗虫猖獗的最佳条件,大旱和特大干旱并不利于蝗灾发生。根据鄂尔多斯高原东南部地区清代蝗灾发生的自然条件预测,在该区降水偏少年,特别是夏季出现轻度、中度旱灾的年份容易发生蝗灾,这时要加强蝗灾的预防。
Through the collection, collation and analysis of historical data, the variation rules of locust plagues, the rank of locust plague, occurrence conditions and their prediction in Qing Dynasty (1644-1911) in Yulin area southeast of Ordos Plateau were studied. The results showed that in the 268 years of the Qing Dynasty, a total of 16 locust plagues occurred in the southeastern Ordos Plateau, with an average of 16.8 a. The mid-Qing Dynasty locust plague is less likely to occur, early and late locust plague occurred more often. In the late stage of 3050 between 1850 and 1879, an average of 4.3a occurred once, and the scale of locust plague was large and severe, causing a large outbreak of locust plague. The locust plague in the area is mainly caused by locally grown locusts. A small number of locust plagues are caused by the relocation of locusts outside the province. Summer locusts and autumn locusts occurred more frequently in the study area, and the number of locust locusts was slightly higher than that of autumn locusts. In the Qing Dynasty, moderate locusts occurred most frequently, followed by mild locusts with the least severe locust occurrence. The correlation coefficient between precipitation and locust occurrence frequency is larger than that of the temperature. The locust disaster is prone to happen in the area where the precipitation is lower than that in the past few years. Mild and moderate droughts are the best condition for locust rampant. The severe drought and severe drought are not conducive to the locust occurrence. According to the natural conditions of the locust plagues in the southeastern Ordos Plateau in the Qing Dynasty, locust plagues are prone to occur in the years where rainfalls are relatively small in this area, especially mild and moderate droughts in summer, and the prevention of locust plagues should be strengthened.