四川省水稻关键生育期不同等级干旱评估研究

Assessment of Different Grade Drought on Critical Growing Period of Rice in Sichuan Province

水稻在四川粮食生产中占重要地位,干旱一直是制约水稻生产的主要因素,夏旱、伏旱频发,造成水稻减产.结合水稻生产的特点和气候条件,选取水分盈亏指数作为干旱评估指标,分析了1961-2014年四川水稻7大种植区不同生育期的干旱时空变化特征及其风险分布情况.结果表明:从时间变化看,各区不同生育期干旱站均次数变化趋势大体相近,尤其是发生次数较高的盆中、盆东和川西南山地,趋势大体相同.干旱相对高值出现在70年代末、90年代末期以及2005年前后,自此以后出现了明显的下降趋势.干旱频率分布特征为全生育期以轻旱为主,以盆中频率最高;孕穗-抽穗期发生轻旱的频率较低,中旱以上发生频率超过50%的地区主要分布在盆中、盆西及盆周地区;抽穗-成熟期以发生轻旱为主,频率较高值分布在盆中、盆南局部和川西南山地部分地区(多在50%以上),中等以上干旱则很少发生.水稻干旱风险分布为全生育与孕穗-抽穗期发生重度及以上风险区域大体一致,主要集中在盆西、盆中的大部、盆周的北部以及川西南山地大部;抽穗-成熟期发生重度及以上风险区域集中在盆东、盆中、盆南和川西南山地局部地区.

Rice plays an important role in the food production of Sichuan Province,where drought has been the primary limited factor-summer drought occurs frequently and reduces rice yield.In this study,water deficit index has been used as a measure of drought and the spatiotemporal variation and the risk distribution of drought been analyzed in different rice growth stages from 1961 to 2014 in the seven rice planting area of Sichuan Province.The results show that the trend of drought is similar in different growth stages,especially in the middle,east and southwest mountainous area of Sichuan,where drought occurred very often.The relatively high value of water deficit index occurred in the late 1970 s,late 1990 sand around2005,and then it shows a significant decreasing trend afterwards.In terms of the characteristics of drought distribution,it was found that light drought dominated the whole development stage and occurred most frequently in the middle of Sichuan.For booting and heading stages,it had lower occurrence of light drought,and the middle level drought with 50% frequency occurred in the middle,west and the surrounding area of Sichuan.As for the heading to mature stage,light drought dominated this period and it was mainly distributed in the middle,east and southwest mountainous area of Sichuan（with 50%light drought frequency）,whereas middle level or more severe drought rarely happened during this stage.When it came to drought risk,severe and above drought risk area was roughly the same for the whole stage and the booting-heading stage,and they were concentrated in the west,large middle,north,and southwest mountainous area of Sichuan.For the heading-mature stage,severe and above drought risk occurred in east,middle,south,and southwest mountainous region of Sichuan.