Risk Assessment Of Japonica Rice Chilling Damage In Northeast China

Japonica rice is widely planted in Northeast China, which plays a decisive role to solve nationalfood issue. Meanwhile, the climate is more sensitive in Northeast China. Redistribution of climateresources due to increased heat resources brings opportunity for japonica rice production in NortheastChina, but also adds uncertainty and of chilling damage risk and increases japonica rice sufferedchilling damage risk. In this paper, took the japonica rice in in Northeast China as research subject, useddaily meteorological data and agricultural production data of japonica rice of69sites, and took themethod of probability statistic, regression and inverse distance weighted interpolation method to assesschilling risk of japonica rice in Northeast China based on the theory of natural disaster risk assessment.Risk probability of different yield reduction rate grades was fitted with normal probability distributionfunction to analyze occurrence probability and intensity spatial distribution of chilling damage loss.Climate risk of japonica rice chilling damage in Northeast China was analysed by delay chilling damageindex and sterile type cool injury index. Chilling damage hazard index, hazard-affected body exposureindex, hazard-affected body vulnerability index, anti-disaster index were designed which were used tocalculate the comprehensive risk of japonica rice with the comprehensive evaluation method.The main conclusions are as follows:1Risk analysis of japonica rice disaster loss showed that the results of japonica rice disaster lossevaluation were different base on diverse evaluation indexes in Northeast China. Yield reductionprobability was not reducing with the yield reduction degree. Range of yield reduction was lower, itsvalue of high risk distribution area was larger. Otherwise，its value of low risk distribution area waslarger. Heilongjiang province belongs to the severe and more severe area, and Liaoning Province is ahigh-incidence mild and moderate reduction area. From the average of yield reduction situation,japonica rice production risk in Northeast China also presents the same characteristics. There were49sites where the coefficient of variation over0.6, accounted for the total study sites71%. So, theproduction of japonica rice was instability in Northeast China.2High risk area of delayed cool injury was distributed in the north of Heilongjiang and east of Jilin;and the more degree of delayed cool injury, the lower probability, the smaller high risk area. Low riskarea of delayed cool injury was distributed in the central and western Jilin province and Liaoningprovince. The spatial distribution of sterile type cool injury was different in different growth period,high risk area of booting stage sterile type cool injury was distributed in the north of Heilongjiang, mildand moderate risk area of serious booting stage sterile type cool injury were distributed in SanjiangPlains, serious sterile type cool injury was distributed in the north of Heilongjiang.3Disaster index was proved reasonal because the correlation of yield reduction rate and delayedcool injury index and sterile type cool injury index were significantly.Further, comprehensive risk indexwas verified reasonable by the correlations of disaster risk index, index of exposure, vulnerability index,anti-disaster and yield reduction rate.Based on the theory of natural disaster risk, a comprehensive riskevaluation model was built to evaluate the chilling damage of japonica rice. The result showed that high chilling injury risk area of japonica rice was in the northern part of Heilongjiang province and Sanjiangplain, and he risk value increased from southwest to northeast.