气象干旱对青海牧草产量的影响及其在产量预报中的应用

Meteorological drought in Qinghai Province:impact on pasture output and application in pasture yield estimation

研究了降水偏少造成的气象干旱对青海省牧草产量的影响，得出牧草生长季降水与产量的关系模式，计算出气象干旱造成的牧草产量损失量。但该方法模拟误差较大，且不能满足牧草产量预报、草场载畜量确定和牲畜出栏率确定等牧业生产服务需求。因此，根据拉格朗日插值方法给出了青海省无干旱时“未受旱产量”的确定方法，并据此求算出历年干旱对青海省牧草产量的损失量值，然后依据天然牧草不同生育期发生干旱的强度、范围以及牧草对干旱的敏感度等关系，建立了干旱损失量的统计和评估模式。在2013-2015年青海省曲麻莱县牧草产量评估中进行了应用，3年的误差在3.59%～6.02％之间，证明了该方法可以评估出研究区干旱对牧草产量的损失量，从而评估出实际牧草产量。拉格朗日插值方法效果较好，可以在青海省今后的牧草产量预报、草场载畜量预报、牲畜出栏率确定等畜牧业生产评估中推广应用。

In this paper, meteorological drought due to fewer precipitation impacting pasture yield in Qinghai Province was studied. A relationship between precipitation in pasture growing season and pasture yield was given. The pasture yield loss affected by the meteorological drought was able to calculate, but the error was large, which was unable to satisfy the requirements of estimating pasture yield, pasture grazing capacity and livestock marking rate. Consequently, the ＂no-drought pasture yield＂ method based on the Lagrange interpolation method was introduced for the scenario that there was no drought in the province. Then the pasture yield loss could be calculated in the province. According to the ＂no-drought pasture yield＂ method, statistics and evaluation model of drought loss could be set up; and then to be applied in pasture yield assessment of Qumarlêb County, Qinghai Province from 2013 through 2015, of which the error was between 3.59% and 6.02 % for the three years. It was proved that using the drought damage assessment method could evaluate the drought loss of pasture yield and assess the actual pasture yield in the study area. This method can be popularized and applied to pasture forecast, pasture grazing capacity prediction and assessment of livestock production in the future.