陇南山区气候变化及其对小麦白粉病流行的影响

根据陇南山区1971～2009年气象资料和相应的小麦白粉病流行资料的对比分析,得出：陇南各地各时段平均气温年际变化趋势十分明显,与1971～2000年平均值比较,2001～2009年年平均气温上升0.6～0.9℃;其中,春季增温最为显著,为0.9～1.1℃,尤以2～3月增幅最大,月平均气温增幅为1.2～1.7℃,由于陇南春季小麦白粉病流行程度与上年9月～次年3月平均气温呈正相关,所以,近10年冬末春初显著增暖趋势与小麦白粉病流行程度逐年加重趋势相一致,由于气候偏暖,与20世纪90年代以前相比,陇南山区冬小麦种植高度及白粉病越冬越夏高界明显提高了100～300m,致使小麦白粉病危害范围扩大,早春发病平均病田率上升10%～20%,发病高峰期由5月上旬提前到4月中、下旬。而陇南各地各时段降水量年际变化趋势不明显,因此,与90年代以前相比,90年代后降水量的变化对小麦白粉病流行的影响变化不大。

The Climate Change and its Effect on Wheat Powdery Mildew in Longnan Mountainous Area

Based on the comparison of meteorological data and wheat powdery mildew data in Longnan mountainous area during 1971-2009,the results showed that there was obvious annual variation of average temperature in each region,and annual average temperature in 2001-2009 was increased by 0.6-0.9 ℃ compared with 1971-2000,especially in winter with the increase of 0.9-1.1 ℃.Meanwhile,the temperature in February and March had highest increase,with the monthly average temperature rise of 1.2-1.7 ℃.There was positive correlation between the epidemic degree of wheat powdery mildew and the average temperature from last September to next March,so the obvious temperature rise at the end of winter and the beginning of spring was consistent with the increasingly severe wheat powdery mildew in recent ten years.Because of climate warming,the planting height of winter wheat and overwintering and oversummering height of powdery mildew increased by 100-300 m compared with the period before 1990s,resulting into the enlargement of hazard scope of wheat powdery mildew.For example,the average disease field rate in early spring rose by 10%-20%,and the disease peak was in the middle and last ten days of April from the first ten days of May.However,there was no obvious change in rainfall,so the effect of rainfall change on wheat powdery mildew after 1990s was smaller than the period before 1990s.