Risk assessment of drought and chilling injury of maize in Northeast China

Abstract: Northeast China is the important commodity grain base of China, but the characteristics of the climate resources in this area show insufficient heat and great differences in regional and seasonal distribution of precipitation, which could lead to the chilling injury, drought and other agriculture meteorological disasters. During the production, especially at the stages of crop growth, the disaster-inducing factor for a particular agriculture meteorological disaster may occur with some disaster-inducing factors for other disasters simultaneously or successively. 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 disasters comprehensively and analyze their effects on the growth of crop. In this study, the meteorological data from 1961 to 2010, maize growth data from 1981 to 2010, production area data from 1961 to 2010 in 35 agriculture meteorological stations, disaster record for the latest 50 years in 3 provinces of Northeast China, and social and economic statistics for the latest 10 years in the counties of these 3 provinces were employed. The drought and chilling injury at two stages of the maize including emergence-tasseling and tasseling-mature was studied based on the theory of natural disaster risk analysis, and the risk of the drought and cold injury to corn in Northeast China was evaluated by emphasizing the creation of the risk assessment index system and risk assessment model. The indices of drought and chilling injury risk assessment model of the maize included hazard, vulnerability, exposure, and emergency response and recovery. Combined the evaluation from disaster index and the record of typical disastrous year, the weights of hazards were made according to the actual drought and chilling damage conditions. The contributions of the compound disaster risk to the whole growth and development of the maize at the early and late stage were 0.347 and 0.6527, respectively. The weights of hazard, vulnerability, exposure and emergency response and recovery ability were explained and provided objectively. These given weights showed that hazard and emergency response and recovery ability were the two most important factors in the model. The risk assessments for the maize drought and chilling damage at different growth and development stages were listed as below: at the early stage, the high values of risk index were distributed in the northwest of Heilongjiang Province, the east of Jilin Province and the northeast of Liaoning Province, while in the southwest of Heilongjiang Province, the west of Jilin and the southwest of Liaoning, the risk index values were relatively low; at the later growth stage, the distribution of the risk index changed, and the risk index values for west Heilongjiang Province and northwest Jilin increased, but decreased considerably in the east of Jilin and northeast of Liaoning. For the whole growth and development period of the maize, the high values of risk index were in the southwest and northeast of Heilongjiang Province and the west of Liaoning Province, with the value of above 0.8; the moderate values were found in the northwest and southeast of Jilin Province and the northeast of Liaoning Province, with the value of between 0.6 to 0.7; the low values were in the central south of Liaoning Province and Liaoning peninsula, with the value of around 0.3.