OBJECTIVE

To study the effects of combined N, P, K and micronutrient fertilizers on the yield of Alisma orientalis tuber, and to optimize the fertilizer application rate.

METHODS

Four factors five levels quadratic orthogonal rotation combination design was used. A function was established on nitrogen, phosphor, potassium and microelement fertilizer application rate with the yield of Alisma orientalis tuber.

RESULTS

The established mathematical model was of high reliability for prediction with quadratic regression equation of R2 = 0. 8980. The order of increasing Alisma orientalis tuber yield was nitrogen>> micronutrient fertilizer>> potassium>> phosphor. The results of the frequency analysis showed that for the target yield over 8 250 kg/hm2 and the confidence interval of 95%, the optimal fertilizer application rates were as follows :nitrogen of 241. 45 - 283. 55 kg/hm2, phosphor of 81. 14 - 208. 44 kg/hm2, potassium of 95. 57 - 239. 42 kg/hm2, and zinc fertilizer of 14. 32 - 16. 18 kg/hm2, boron fertilizer of 18. 84 - 19. 86 kg/hm2, and molybdenum fertilizer of 0. 151 -0. 159 kg/hm2 in micronutrient fertilizer.

CONCLUSIONS

Nitrogen is related to the growth of Alisma orientalis, potassium promotes tuber bulking, micronutrient fertilizer consisted of zinc, boron and molybdenum fertilizer promotes Alisma orientalis growth and the absorption of nitrogen, phosphor and potassium. Moderate application of nitrogen, phosphorus, potassium, zinc, boron and molybdenum fertilizer can promote Alisma orientalis tuber yield. The nitrogen has the best effect.