Nutrient Contents in Paulownia and Soil and Their Effects on Witches'Broom

The paper deals with the relationship between contents of available nutrients in soil and nutrients in Paulownia leaves by using comparative analysis,The relation between P/Cu,P/Fe,P/Zn and P/K in soil and that in Paulownia leaves is significant positive correlation (r=0.918^**).This shows that there is a relationship between incidence of Paulownia withches' broom and contents of available nutrients in soil and of elements in leaf.Low phosphorus and high copper contents in soil and the antagonistic action among elements in soil and in plant are the reasons that the contents of potassium and copper in Paulownia leaf are exorbitant and manganese and phosphorus are deficient.So the proper ratios of P:K,Fe:Mn and Cu:Mn are disrupted by the excessive potassium and copper in the leaf ,which,in turn,interferes the normal metabolism of Paulownia and reduce its resistance to witches' broom.