寒地水稻关键生育期涝害的过程雨量指标构建

Establishment of process rainfall indices for waterlogging damage in key growth stage of rice in cold region

建立寒地水稻涝害的过程雨量指标对寒地水稻应对气候变化、防灾减灾、安全生产意义重大。本研究以黑龙江省粳稻为研究对象,基于1961—2000年长序列水稻灾情史料、生育期资料及研究区73个气象观测站逐日降水量资料,采用统计方法,反演水稻关键生育期涝害的降水日数及过程雨量,建立寒地水稻涝害样本过程雨量序列。利用K-S分布拟合检验,采用置信区间下限值确定阈值方法,构建寒地水稻涝害过程雨量等级指标;并用预留的灾害样本对指标进行验证。结果表明:在农田排水不畅条件下,降水过程在1～3 d之间水稻轻度、中度和重度涝害雨量下限值分别为分蘖期48、89、136 mm,抽穗期44、87、102 mm;降水过程在4～7 d之间水稻轻度、中度和重度涝害雨量下限值分别为分蘖期68、97、142 mm,抽穗期66、103、127 mm。指标计算结果与历史灾情记录吻合度较高。研究结果为开展寒地水稻灾损定量评估提供基础支撑。

The establishment of process rainfall indices for waterlogging damage to rice in cold region is important for coping with climate change,preventing and mitigating natural disasters,and ensuring production safety.Based on historical data of waterlogging damage and phenophase of japonica rice from 1961 to 2000,combined with daily precipitation data of 73 meteorological stations,we inverted rainy days and process rainfall of waterlogging at the key growth period of rice and established the process precipitation sequence of cold rice waterlogging samples,with japonica rice in Heilongjiang Province as the research object.The precipitation level index of waterlogging process of rice in cold regions was constructed by using K-S distribution fitting test and the lower limit value of confidence interval to determine the threshold value.The indices were verified with the reserved disaster samples.The results showed that under the condition of poor drainage of cropland,when rainy days were within 1-3,the lower limits of rainfall for rice with mild,moderate and severe waterlogging were 48,89 and 136 mm at tillering stage,and 44,87,102 mm at heading stage,respectively.When rainy days were within 4-7,the lower limit values of rainfall were 68,97 and 142 mm at tillering stage,and 66,103,127 mm at heading stage,respectively.The calculated results of the indices were well consistent with the historical waterlogging damage records.Our results can provide support for quantification of rice waterlogging damage in cold regions.