毛乌素沙区灌木立地质量数量化表两种编制方法的比较

A Comparison of Quantitative Tables of Site Quality for Shrubs Established by Two Different Methods

应用两种方法编制了毛乌素沙区常见的８种灌木的数量化表。第一种方法用数量化理论（Ⅰ）模型，直接编制灌木生物量对各立地因子的数量化表，第二种方法应用经济计量学中联立方程模型的建模思想，将数量化理论（Ⅰ）模型与多元回归模型结合起来，先分别编制灌木种的冠幅、灌高对各立地因子数量化表，然后将其所得数值代入各灌木种生物量（单株／丛干重）对冠幅、灌高的多元回归模型中。最后通过理论值与实际值计算出相对误差值。结果是第一种方法编制的８个灌木种数量化表，相对误差为１０％～１９％，第二种方法编制的８个灌木种数量化表相对误差为４６％～３５９％。

Two different methods were used to establish the quantitative tables of site quality for 8 common species of shrubs: Caragana intermedia;Caragana korskinskii; Hedysarum scoparium; Hedysarum laere;Salix spammo-phila; Artemisia ordosica; Artemisia sphaerocephala and Hippophae rhammoi-des. Weight of biomass of the shrubs was used as an index to establish the tables.The model of quantitative theory (Ⅰ) was used to establish the first table. The second table was established by using the combination of model of quantitative theory (Ⅰ) and model of multiple regression. At first,the quantitative tables of the crown width and shrub height were worked out,then the data was used in the model of multiple regression. Finally, the relative errors were calculated through theoretic values and realistic values.The relative errors of the first table was 10%～19%, while those of the second one 46%～359%.