By means of these two equations, Xm and Qm are calculated, and it is found that the Xm and Qm are affected by pH,content of clay, CaCO3, available phosphate, saturation coefficent of Ca2+ and Mg2+,and so on.

• 根据二式求出的Xm、Qm主要受土壤pH、粘粒含量、CaCO3、有效磷、Ca2＋、Mg2＋饱和度的影响。