Changes of nitrogen, phosphorus and potassium in five-year-old Schisandra chinensis leaves at different growth stages.

[Objective] To study the changes of nitrogen(N),phosphorus(P) and potassium(K) contents in 5-year-old Schisandra chinensis(Turcz.) Baill.leaves at different growth stages.[Method] Dichromic acid K capacity method-outside heating method was used to determine the soil organic matter.Alkaline hydrolyzation diffusion method was used to detect the alkali-soluble N.And 0.5 mol/L NaHCO3 extraction-Mo-Sb colorimetric method was used to detect rapidly available P;NH4OAC extraction-flame photometry was used to detect rapidly available K;H2SO4-H2O2 method was used to digest the plant sample.Total N was detected by distillation titration method;total P was detected by V-Mo yellow colorimetric method;total K was detected by flare photometer.Changes of N,P and K contents in 5-year-old S.chinensis leaves at different growth stages were detected.[Result] S.chinensis leaves had the strongest absorption capacity to N in all growth period,followed with K.And P had the smallest absorption.N and K contents in S.chinensis leaves were relatively high in leaf-expansion period;N and K contents fell smoothly from flowering stage to wilting stage.P content was relatively high in leaf-expansion period and from late berry growth stage to early fruiting stage,and decreased greatly in late fruiting stage.[Conclusion] Artificial cultivation of S.chinensis needed enough base fertilizer and top-dressing of P was also needed at berry growth stage.