Risk Assessment Of Drought And Chilling Injury Of Maize In Northeast China

Northeast China is the important commodity grain base of China, but the characteristicsof the climate resources in this area including insufficient heat and great differences inregional and seasonal distribution of precipitation, could lead to the chilling injury, droughtand other agriculture meteorological disasters. During the production, especially at the stagesof crop growth, the disaster-induce factor for a particular agriculture meteorological disastermay occur with some disaster-induce factors for other disasters simultaneously orsuccessively. So the final output of the crop was also influenced by various factors together.Therefore, it was of more practical significance to consider the major disasterscomprehensively and analyze their effects on the growth of crop. In our study, themeteorological data from1961to2010, maize growth data from1981to2010, productionarea data from1961to2010in35agriculture meteorological station, disaster record for thelatest50years in3provinces of Northeast China, and social and economic statistics for thelatest10years in the counties of these3provinces are employed. We studied the drought andchilling injury at two stages of the maize including emergence-tasseling and tasseling-mature,based on the theory of natural disaster risk analysis, evaluated the risk of the drought and coldinjury to corn in northeast China by emphasizing the creation of the risk assessment indexsystem and risk assessment model. The main conclusions in this thesis are listed as below.(1) Drought index and chilling injury index were created according to the crop waterdeficit index and heat index. The risk of maize drought and chilling injury in Northeast Chinawere analyzed. The result showed at the early stage of maize growth and development, thedisaster mainly concentrated in the southeast of the studying area with chilling injury as themajor disaster; while at the later stage, the drought of the west part in northeast China was themajor meteorological disaster.(2) Based on the theory of natural disaster risk analysis, the drought and chilling injuryrisk assessment model of maize including hazard, vulnerability, exposure, and emergencyresponse and recovery in Northeast China were created. Combined the evaluation fromdisaster index and the records of typical disastrous year, the weight of hazard were made according to the actual drought and chilling damage conditions. The contributions of thecompound disaster risk to the whole growth and development of the maize at the early andlate stage were0.347and0.6527, respectively. The weight of vulnerability, emergencyresponse and recovery ability, and risk evaluation are explained and provided objectively.These given weights showed hazard and emergency response and recovery ability were thetwo most important factors in our model.(3)The risk assessment for the maize drought and chilling damage at different growthand development stages were listed as below: at the early stage, the high value of risk indexwere distributed in the northwest of Heilongjiang Province, east of Jilin Province andnortheast of Liaoning Province; while in the southwest of Heilongjiang province, west of Jilinand southwest of Liaoning, the risk index values were relatively low. At the later growthstage, the distribution of the risk index changed, the risk index value for west Heilongjiangprovince and northwest Jilin increased, but in the east of Jilin and northwest of Liaoning, theindex value decreased considerately. For the whole growth and development period of themaize, the high value of risk index were in the southwest and northeast of HeilongjiangProvince, west of Liaoning province, with the value above0.8; the moderate value werefound in the northwest and southeast of Jilin province, and northeast of Liaoning province,with the value between0.6to0.7; the low value were in the central south of Liaoningprovince and Liaoning peninsula, with value around0.3...