关键词: 东北玉米, 冷害, 干旱, 涝害, 风险评价, 区划

Abstract: 【Objective】Northeast China, one of China’s key grain production bases, witnessed unstable maize yield caused mainly by such meteorological disasters as chilling, drought and flood, and risk assessment of the main meteorological disasters threatening maize in Northeast China at different growth stages and the whole growth period will provide a scientific basis for regional agricultural production planning and meteorological disaster prevention and alleviation. 【Method】Based upon the theory of natural disaster risk and the formation mechanism of agro-meteorological disaster risk, the established risk assessment index system and the risk assessment model of growth stages and the whole growth period aiming at the main meteorological disasters threatening maize in Northeast China were used to assess four elements (hazard of the natural disasters as chilling, drought and flood, exposure and vulnerability of the disaster-affected body and the disaster prevention and mitigation capacity of human beings) at four growth stages, namely sowing to seven-leaf, seven-leaf to tasseling, tasseling to milky ripening and milky ripening to maturation. After that, risk of the main meteorological disasters in each growth stage and of the whole growth period was assessed and zoning of the assessment result was identified in the system cluster analysis. 【Result】 Generally the hazard of chilling damage increases from west to east and are in zonal distribution at each growth stage. In early stages, areas with medium or high values of the hazard of chilling are in Changbai Mountain area and Southeast Heilongjiang; at later stages, the areas with medium or high values of the hazard of chilling are mostly in Changbai Mountain area and southeast and north of Heilongjiang research area. Generally the hazard of drought increases from east to west or from southeast to northwest and are in zonal distribution at each growth stage. While the hazard of flood present obvious regional differences at each growth stage with Southeast Liaoning being an area easy to be affected by flood. Of the four growth stages, it is less likely to have flood at the stage of sowing to seven-leaf in the research area. At the subsequent three stages, the areas with high hazard of flood are mainly in Southeast Liaoning. At the stage of sowing to seven-leaf, the main meteorological disaster risk are in zonal distribution from northeast to southwest: areas with low or medium risk values are in central Northeast China while those with medium or high values are mostly in west and east of Northeast China. At the stage of seven-leaf to tasseling, the main meteorological disaster risk increases from northeast to southwest: areas with low or medium risk values are mainly in Heilongjiang and central and northeast of Jilin, while those with medium or high values are in the west of Northeast China, Southeast Jilin and south and east of Liaoning. At the stages of tasseling to milky ripening, milky ripening to maturation and even the whole growth period, the main meteorological disaster risk increases from east to west and the areas with medium or high risk values are mostly in the western part of Heilongjiang research area, west Jinlin and a large part of Liaoning. At the sowing to seven-leaf stage, the areas with high risk of the main meteorological disasters are in Qinggang, Dongning, Baicheng, Qian’an and Changbai, and most areas face medium risk. At the seven-leaf to tasseling stage, the high risk areas are in Southeast Liaoning’s Kuandian, Xiuyan and Zhuanghe; in the first two growth stages, the high risk regions are distributed sporadically or cover a relatively small area. In tasseling to milky ripening, milky ripening to maturation and the whole growth period, the high risk regions expand and are stretched in the west of Heilongjiang research area, west Jilin and east Liaoning’s Kuandian and Xiuyan.【Conclusion】The risk of the main meteorological disasters, namely chilling, drought and flood, threatening maize in Northeast China at each growth stage and of its whole growth period, are distributed in different patterns. At the first two growth stages, the high risk regions cover a relatively small area; at the last two growth stages and in the whole growth period, the high risk regions expand and are stretched in the west of Heilongjiang research area, west Jilin and east Liaoning’s Kuandian and Xiuyan.

Key words: maize in Northeast China, chilling damage, drought, flood, risk assessment, zoning