氮磷钾配施对茶叶品质的影响

Effects of Combined Application of N,P and K on the Quality of Tea

以茶叶品种金牡丹为试验材料,采用二次饱和D-最优设计(311)进行盆栽试验,对茶叶主要品质指标进行2次回归拟合,探求茶叶适宜的氮磷钾施用量和配比。结果表明:氮磷钾配施对茶叶各品质指标均有显著影响,且对于游离氨基酸、茶多酚和咖啡碱含量,氮素影响最大,磷次之,钾最小;对于水浸出物,氮素影响最大,钾次之,磷最小。单因素施肥效应分析表明,茶叶各品质指标均随氮、磷、钾施用量的增加而增加,达到最高值后,又随施用量的增加而降低。氮磷钾双因素施肥效应分析表明,氮钾互作对茶叶水浸出物和游离氨基酸总量有显著影响,磷钾互作对茶叶游离氨基酸总量影响显著,氮磷互作对茶多酚和咖啡碱含量有显著影响。本试验条件下,茶叶优质的氮、磷、钾施肥方案为N 0.55 g/(kg·土),P2O50.24 g/(kg·土),K2O 0.22g/(kg·土),适宜的氮磷钾施用比例约为N:P2O5:K2O=2.75:1.2:1.1。

Tea cultivar Jinmudan was pot cultured in a quadratic saturation D-optimal design （311） and a quadratic regression fitting of main quality indexes of the tea was made to find optimal application rates of N, P and K and their ratio in pot culture of the tea. The results showed that combined application of N, P and K had significant effect on the quality of tea. N element showed the highest effect on free amino acids, tea polyphenols and caffeine, followed by P and then K. N element also had the highest impact on the water extract, followed by K and then P. Single factor fertilizer experiment showed that the quality of tea increased with the application rate of N, P or K, and then, after reaching the highest value, decreased with an increase in application rate of N, P or K. Double factor fertilizer experiment showed that the N and K interaction, P and N interaction and N and P interaction had significant effects on the water extract and total free amino acid content of the tea, on the total free amino acid content of the tea, and on tea polyphenols and caffeine, respectively. Under the condition of this experiment, it was concluded that the optimal rates of N, P, K fertilizer applied to the tea was N 0.55 g/kg, P205 0.24 g/kg, K20 0.22 g/kg, with an appropriate proportion of N, P and K being N： P205 ： K20=2.75 ： 1.2 ： 1.1.