基于降水距平的黄淮平原夏玉米干旱评估指标研究

以降水和产量资料为基础,研究确定了夏玉米干旱评估指标。首先对历史产量序列进行处理,利用三次多项式拟合趋势产量,分离相对气象产量;分析不同生育阶段降水距平和相对气象产量的相关关系,结果表明,玉米出苗~抽雄期降水距平与相对气象产量呈显著的正相关;通过统计分析,建立了它们之间的回归方程,并结合农业干旱划分标准,确定了夏玉米生长季不同等级的农业气象干旱指标,即降水负距平<20%、20%~50%、50%~80%、>80%时,分别出现轻旱、中旱、重旱和严重干旱,产量分别减少<10%、10%~20%、20%~30%、>30%。

Research on drought assessment index of summer maize base on precipitation anomaly

The drought assessment index of summer maize was determined based on the relationship between precip-itation and yield. Firstly, the history data series of yield were processed, trend yield was fitted using cubic polynomial, and the relative meteorological yield was detached; and then the relationship between precipitation anomaly in different growing phase and relative meteorological yield was analyzed. The result showed that precipitation anomaly from emer-gence to teaseling stage had significant positive correlation with relative meteorological yield. The regression equation was established through statistic analysis. The drought assessment index of summer maize in different grade was determined combined with division standard of agricultural drought. The index was: when negative precipitation anomaly was<20%,20%~50%,50%~80%,or>80%, the drought grade was slight drought, middle drought, heavy drought and serious drought, and the yield reduction was<10%, 10%~20%, 20%~30%, or>30%.