淮河流域冬小麦主要生育期旱涝时空特征及对产量的影响

旱涝灾害在淮河流域发生频繁,对农作物产量影响较大。该文基于淮河流域1961-2014年140个气象站逐日降水、气温数据,利用标准化降水指数(standardized precipitation index,SPI)和标准化降水蒸散指数(standardized precipitation evapotranspiration index,SPEI)定量分析冬小麦各生育期气候特征,结合1961-2012年20个站点冬小麦单产数据计算标准化产量残差(standardized yield residuals,SYR),探讨冬小麦主要生育期旱涝灾害对其产量的影响。结果表明:1)冬小麦各生育期气温均呈显著上升趋势(P0.05),气温呈南高北低、西高东低的格局,东部趋势高于西部且返青抽穗期大部分站点趋势值最高,而降水量沿纬度变化与气温一致,其变化趋势在冬小麦各生育期差异明显。2)冬小麦返青抽穗期干旱增加趋势最大(P0.05),旱涝灾害在全生育期、返青抽穗期和灌浆成熟期主要受气温影响,在冬前生长期和越冬期主要受降水量影响,同时冬小麦各生育期SPEI干旱化趋势大于SPI。3)除冬前生长期外,SYR与SPI和SPEI均呈负相关关系,以返青抽穗期相关性最高,在返青抽穗期达到中度干旱或中度湿润时产量减少。该研究尝试明晰淮河流域发生在冬小麦生育期的旱涝灾害对其产量的影响,为冬小麦生育期防灾减灾提供基础支撑。

Space-time characteristics of drought and flood in main growing periods of winter wheat in Huaihe River Basin and its impact on yield

Abstract: Droughts and floods occur frequently in Huaihe River Basin, which has a great impact on crop yield. Based on daily mean temperature and precipitation data of 140 meteorological stations from 1961 to 2014, the standardized precipitation index (SPI) and standardized precipitation evapotranspiration index (SPEI) in each growth period of winter wheat were calculated, and quantitative analysis of climatic characteristics of winter wheat at different growth stages was carried out. Meanwhile, the standardized yield residual (SYR) was calculated to investigate the effects of dry and wet conditions on yield at different growth stages based on the winter wheat unit yield data of 20 sites from 1961 to 2012. Firstly, the variation tendency of mean temperature and precipitation in each growing period of winter wheat was analyzed according to the linear regression. The mean temperature rose significantly and the mean rainfall mainly showed a downward trend in each growing period. According to the Mann-Kendall trend method, the trend values of mean temperature and precipitation in winter wheat growth period were calculated and the spatial characteristics were analyzed. The mean temperature in the south was higher than that in the north and had an increasing pattern from east to west, the trend in the east was higher than that in the west and most of the sites had the highest level of trend in turning green and heading stage. However, the precipitation increased with the decrease of latitude, and the trend was consistent with the temperature in latitude. Secondly, according to the Mann-Kendall trend method, the trend values of SPI and SPEI in winter wheat growth period were calculated, and the increase trend of drought was the biggest in turning green and heading stage at the significant level of 0.05. Comparing the spatial features of SPI and SPEI changing trends, it was found that the drought-flood disaster was affected by temperature in whole growth period, turning green and heading stage and milking ripening period of winter wheat, and was affected by precipitation in growth period before winter and over-wintering stage of winter wheat. And the trend of drought indicated by SPEI was greater than that by SPI. Finally, the correlation between SYR and SPI/SPEI was analyzed using Pearson correlation method to determine the most relevant stage of winter wheat, and then the drought and flood situation of winter wheat was analyzed. There was negative correlation between SYR and SPI/SPEI except growth period before winter, with the highest correlation in turning green and heading stage. When moderate drought or humidity occurred, the yield of winter wheat began to decrease. This research is of guiding implications to the prevention of disaster and yield reduction of winter wheat in Huaihe River Basin.