黄淮中部小麦干旱的发生规律及成因分析——以商丘市为例

Analysis on the Occurrence and Cause of Wheat Drought in Central Huanghuai——Taking Shangqiu City as an Example

以1971—2010年商丘市小麦生长季的气象数据为资料,系统地研究了小麦生育期干旱的发生规律,并分析了形成原因。结果表明,黄淮中部小麦干旱发生频率为10年8遇,重灾年率分别为10年6～7遇。与常年相比,干旱呈现发生频率变化不大,在特殊生育期逐渐加重的趋势;干旱在越冬期发生频率最高,年际间变化较大;返青至开花阶段频率次之,年际间变化较小;播种至出苗期频率最小,但呈逐渐增加趋势;空间分布呈现东部和南部少,中部次之,北部和西部多的特征。形成原因方面来看,商丘区域为西北气流控制,常出现持续少雨天气,致使旱灾发展,其中永城和民权由于土壤因素蒸发量大也可以造成干旱的发生;整地质量和浇水次数等一些人为因素也可能导致干旱的发生。

Taking the meteorological data of the wheat growing season in Shangqiu City from 1971 to 2010 as the data,the law of occurrence of drought in the wheat growing period was systematically studied,and the reasons for the formation were analyzed.The results showed that the frequency of wheat drought in central Huanghuai was 8 years in 10 years,and the annual rate of severe drought was 6-7 years in 10 years.Compared with the perennial drought,the occurrence frequency of drought showed little change,and it gradually increased during the special growth period.Drought had the highest frequency in the overwintering period and changed greatly during the interannual period. The frequency of returning to the flowering stage was the second,and the interannual variation was relatively small. The frequency of sowing to the seedling stage was the smallest,but it gradually increased.The spatial distribution showed that drought was less in the east and south,followed by the middle,and more in the north and west.From the aspect of formation reasons,the Shangqiu area was controlled by the northwest air flow,and continuous and dry weather often occured,which resulted in the development of drought. Among them,Yongcheng and Minquan could cause drought due to large evaporation of soil factors.Some human factors such as the quality of soil preparation and the number of waterings might also cause drought.