陇中地区玉米春霜冻害等级指标研究

为明确霜冻强度与农作物冻害程度之间的量化关系,以陇中地区玉米春霜冻害为研究对象,从霜冻灾害的致灾因子的危险性和承灾体的脆弱性出发,建立玉米冻害等级指标。主导指标采用最低地温负距平,能够反映玉米关键生育期作物耐寒程度的动态变化,实现了霜冻强度与作物生育期的结合;辅助指标采用逐时负地积温与日最低地温,体现霜冻强度是低温强度与低温持续时间的累计效应;再参考作物受冻率,构成了完备的春霜冻害指标体系。该指标计算简便,物理及物候学意义显著,经检验与实际情况吻合度达到80%,可在业务中推广应用。

Level Indexes of Spring Frost Disasters to Corn in Central Gansu Province

The paper aims to clarify the quantitative relationship between frost intensity and frost damage degree of crops, taking spring frost damages to corn in central Gansu Province as research objects, and from the research points of hazard-formation factors and vulnerability of hazard-affected bodies, the level indexes of spring frost disasters to corn were established. The authors used negative anomaly of surface minimum temperature as the leading index, which could reflect the dynamic change of cold tolerance of crops in key growth stages, and could combine frost intensity and growth stage of crop; selected supplementary indexes as hourly negative accumulated surface temperature and surface minimum temperature, which could reflect that the frost intensity was the cumulative effect of intensity and duration of low temperature; at last, the authors referred to crop freezing rate, and constructed a complete index system. The indexes could be calculated easily and had obvious physics and phenology significance. Upon examination, the real agreement and the basic agreement rate of the indexes could reach 80%, indicating that the indexes could be applied to practice.