Temporal And Spatial Distribution Characteristics And Catastrophic Laws Of Rice Chilling In Northeast China

Northeast China is the main area for rice planting in China,accounting for 15% of the country's total area.However,it is highly susceptible to chilling damage during rice growth,resulting in reduced yield.In recent years,with the impact of climate warming,changes in cropping systems,and variety replacement,the occurrence of chilling damage has changed.This paper uses the meteorological data of 190 meteorological stations in Northeast China from 1981 to 2015,combined with rice production and disaster data,to analyze the spatial and temporal distribution characteristics and catastrophic laws of delayed chilling damage and obstacle chilling damage in Northeast China.The climate risk index is constructed by using the coefficient of variation and risk index to classify the risk of cold damage in the northeast region.The main conclusions are as follows:(1)From the perspective of time trends,the station order of various types of delayed chilling damage stations in the northeastern region showed a downward trend.The order of the downward trend is,severe > moderate > light.The frequency of obstacle chilling damage has a downward trend.The frequency of chilling damage at heading-flowering stage was significantly higher than that at booting stage.In the 1980 s and 1990 s,the frequency of chilling damage occurred more frequently than in the 21 st century.The delayed ratio of chilling damage stations showed a downward trend,and mutations occurred around 1996.The results of period analysis show that there is a significant change period of 4~5a and 13~14a in the periodic variation of the delayed chilling damage stations.There is a quasi-period of 4a and 8a at the booting stage and there is a quasi-period of 8a and 13 a in the heading-flowering stage of obstacle chilling damage.(2)The frequency of rice cold damage caused by rice in Northeast China showed a clear spatial distribution,which showed an increasing trend from south to north.For delayed chilling damage,the high-incubation area with mild chilling damage is in the southern part of Heilongjiang Province and most of Liaoning Province;the high-incidence area with moderate chilling damage is the Inner Mongolia East Four League and the northern part of Jilin Province;the high-incidence area with severe chilling damage is the northern part of Inner Mongolia Dongsi League and the northeast of Heilongjiang Province.For obstacle chilling damage,the high-incubation area with mild obstacle chilling damage is the northern part of Heilongjiang Province and the northern part of Inner Mongolia.The high-risk area with moderate is the northwestern part of Inner Mongolia East Four League,the northeastern part of Heilongjiang Province and the southeast of Jilin Province.The high-risk area with severe chilling damage is Heilongjiang Province and northwestern of Inner Mongolia East Four League.Mild chilling damage and moderate chilling damage occur more.(3)Divide the northeast region into five delayed climate risk zones: Hailar and Erguna in the northern part of Inner Mongolia are high-risk areas;Xiaoergou in the northern part of Inner Mongolia,and Nenjiang in the north of Heilongjiang Counties and cities are higher risk areas;Zhaoyuan in the south of Heilongjiang Province,Tongjiang in the east of Heilongjiang Province,Gangzi in the south of Inner Mongolia's Dongsi League,and Zhalantun in the northeast are moderate risk zones;Xinmin in the north of Liaoning Province The counties and cities such as Dandong in the southeast are lower risk areas;Donggang in the southeast of Liaoning Province;Xingcheng and Suizhong counties in the southwest are low-risk areas.