山西省玉米的干旱当量与干旱分区

本文以山西省玉米种植生态区为基础 ,应用阿齐的干旱当量方法 ,对山西省 72个县、市1 62 3年次的降水资料和玉米产量资料进行计算 ,归纳分析 ,认为山西玉米产量丰、歉与降水的关键期有密切关系 ,分别为 :夏播中早熟区关键期为 7月 2 0日～ 7月 30日 ,干旱当量为 2 9 9 。春播早熟区关键期为 5月 2 1日～ 6月 2 0日 ,干时当量— 37 8 。春播中晚熟区关键期为 5月 1 0日～ 6月 2 0日 ,干旱当量为 34 0 。根据关键期的干旱频率按级差为 2 5作干旱程度分区。微旱区 (频率指标 0 1～ 2 5 ) ,轻旱区 (频率指标 2 6～ 5 ) ,干旱区 (频率指标 5 1～ 7 5 )。

Water Equivalents and Drought Division of Maize in Shanxi Province

Based on the ecological section of Shanxi Province,according to G.Ace's theory of meteorological equivalent,and analyzing the stations and the maize yielding information of 1623 years of 72 counties,we found:the poor and good harvest of maize in Shanxi Province depends on the key factor critical period of rainfall.It can be divided into the following periods:the critical period in spring seeding and early ripeness region(from 21 May to 20 June),drought equivalent is 37.8 mm;the critical period in spring seeding and middle late region(from 10 May to 10 June),drought equivalent is 34.0mm;the critical period in summer seeding(from 20 July to 30 July),drought equivalent is 29.9mm.According to the drought frequency during critical period and the range is 2.5,it can be divided into the following regions:the micro-arid region(frequency index 0.1-2.5),light arid region(frequency index 2.6-5),and arid region(frequency index 5.1-7.5).