桤木结瘤固氮与土壤理化因素的关系,可用多元二次回归方程表达。最佳数学模式表明:影响固氮量的主要因素是酸度,其次是有效磷与有效钾、CO_2与有机质、CO_2与有效钼的联合效应。有效磷的不足是固氮的限制因素。共生体的固氮能力在潮土和黄壤(灰岩母质除外)上最强,沙溪庙母质的各种紫色土较高,强钙质土和酸性土则低。 Nodular nitrogen fixation and soil physical and chemical factors, multivariate regression equation can be used to express. The best mathematical model shows that the main factors influencing the amount of nitrogen fixation are acidity, followed by the combined effect of available phosphorus and available potassium, CO 2 and organic matter, CO 2 and available molybdenum. Insufficient phosphorus is a limiting factor for nitrogen fixation. Nitrogen fixation ability of symbiont is the strongest in the Chao soil and yellow soil except the parent material of limestone. The various purple soil of Shaxi temple parent material is high, while the strong calcareous soil and acid soil are low.