Comprehensive Spatio-Temporal Evolution Of Summer Maize Drought In Huang-Huai-Hai Plain

This study used meteorological data of 76 stations from 1981 to 2015 in Huang-Huai-Hai plain,summer maize growth period and yield data,took crop water deficit index(CWDI)as the drought index,using the drought station proportion,the drought frequency,Arcgis spatial interpolation,correlation analysis to analyze the spatio-temporal evolution characteristics of summer maize drought in this plain.The main conclusions were as follows:1)In terms of time,in the sowing-emergence stage,extreme drought was the main occurrence type.Typical drought years were 1981,1997,2001,2011 and 2012.In jointingtasseling stage,light and moderate drought were the main occurrence types.The typical years of light drought were 1981,1987,1994,2006 and 2009,and the typical years of moderate drought were 1982,1983,2002,2010 and 2012.In tasseling-milking stage,light and moderate drought were the main occurrence types.The typical years of light drought were 1990,1995,2003,2005 and 2006,while the typical years of moderate drought were 1983,1988,1992,2010 and 2012.The other growth stages were less affected by drought.In the whole growth stage,1981,1983,1988,1994,1997,1999,2001,2002,2006,2010 and 2011 were typical drought years in the past 35 years.After 2000,the light drought tended to rise,while the extreme drought tended to fall,and the 1990 s was the worst decadal of drought from 1981 to 2015.2)In the spatio-temporal scale,in the sowing-emergence stage,extreme drought was the main occurrence type,which occurred more frequently in the 1990 s.The center of extreme drought were located in most of Hebei and the northern of Shandong.In jointing-tasseling stage,light and moderate drought were the main occurrence types,both of which occurred more frequency in the early 21 s.The light drought centers were located in most of Anhui and Jiangsu,as well as the southern of Shandong,while the moderate drought centers were located in most of Henan and Shandong,as well as the southern of Hebei.In tasseling-milking stage,light and moderate drought were the main occurrence types.Light drought occurred more frequently in the early 21 s,while moderate drought occurred more frequently in the 1980 s.The light drought centers were located in most of Anhui and Shandong,as well as the southern of Hebei,while the moderate drought centers were located in most of Henan,Shandong and Anhui,as well as the southern of Hebei.The drought frequency was low in other growth stages.The whole growth period was dominated by ligh drought,followed by the moderate drought,severe drought and extreme drought frequency was lower.The drought frequency decreased with the increase of drought level.The central area of Huang-Huai-Hai was a higher drought plain.3)The drought in Huang-Huai-Hai plain had the greatest effect on summer maize yield in Shandong province,which reached an extremely significant level with the correlation coefficient above 0.49.Secondly,Anhui province reached the significant level with the correlation coefficient above 0.40.The impact on the yield of Henan,Hebei and Jiangsu was less.