Effects of NPK Fertilizer on Yield and Total Saponin Contents in Paris polyphilla var. yunnanensis

Paris polyphylla var. yunnanensis is an expensive genuine medicine material in China. It is endangered due to excessive excavation in recent years. Artificial cultivation of P. polyphylla var. yunnanensis is an important measure to resolve supply problem and rational application of NPK fertilization can increase yield and medical quality.3414 fertilization experiment were conducted with regular fertilization of NPK (N:23 kg/667 m2, P2O5:12 kg/667 m2, K2O:30 kg/667 m2) was carried out to study the effect of different rates of NPK fertilization on yield and total saponin content of rhizome.The result showed that contributions of soil NPK fertility were 77.97%,64.93% and 136.52%,respectively,the content of potassium in soil was abundant, and nitrogen was in middle degree, phosphorus was deficient. N and P fertilizer application increased yield and saponin content of rhizome.It showed that single application of nitrogen, phosphorus, potassium fertilizer increased little yield of rhizome,combination of nitrogen, phosphorus and potassium with a significant effect on increasing rhizome yield. It had a highest growth rates in P. polyphylla rhizome yield(87%)with applying optimum amount of fertilizer (N:34.5 kg/667 m2, P2O5:18 kg/667 m2, K2O:0 kg/667 m2). The study showed that N fertilizer and P fertilizer could improve the content of saponin in new and old rhizome of P. polyphylla var. yunnanensis, K fertilizer reduced the content of saponin in new rhizome. The saponin content reached the maximum when N and P2O5 application rates were 23 kg/667 m2 and 18 kg/667 m2,respectively.The content of saponin in new rhizome of P. polyphylla was the highest when K fertilizer application rate was 0 kg/667 m2.