东亚飞蝗蝗蝻抽样的研究

自五十年代以来,应用于东亚飞蝗蝗区估计蝗蝻种群密度的抽样方法,是样方为10平方尺的筒单随机抽样。本文是以抽样数、抽样消耗、相对精确度为标准,对三种抽样模型、三个抽样单位进行了比较。根据这些结果,我们提出了在当前蝗蝻密度较低的情况下,应采用样方为100平方尺的最适配额分层抽样。这种抽样方法在精确度方面可以高出现用的抽样方法2倍以上。而抽样时间消耗可相对节约一半以上。

STUDIES ON THE SAMPLING METHOD OF NYMPHAL STAGE OF THE ORIENTAL MIGRATORY LOCUST(LOCUSTA MIGRATORIA MANILENSIS)

Since the end of the fifties,the sampling method for estimating the population density of nymphal stage in the locust outbreak areas is simple random sampling with sampling units of 3.3m².As a result of combined measure of reconstruction and chemical control,through more than ten years,the population density of this pest has been markedly decreased.In such low density condition,from economic point of view what suitable sampling method ought to be taken for nymphal stage should be ascertained.In this paper,several comparisons between three sampling methods(i.e.simple random sampling,stratified sampling for proportion,and stratified sampling for optimum allocation)and three types of sampling units(i.e.3.3m²,16.5m²,33m²),are made with respect to sample sizes,sample cost,and relative precision etc.According to these results,a suitable sampling method is proposed,that is stratified sampling for optimum allocation with 33m² of sampling unit.The relative precision for this sampling is higher 2.2 times than that of the sampling method usually used and the relative time cost is 2 times less.