明确抚育间伐对千年桐-闽楠混交林的磷动态结构干扰机制,为千年桐-闽楠混交林土壤磷素的科学管理提供依据。以福建南平范桥国有林场5 a生千年桐和闽楠为对象,测定其土壤全磷、有效磷含量以及枝、叶、干、根全磷含量,研究抚育间伐对其根际土和营养器官磷含量的影响。结果表明:1)千年桐与闽楠根际磷富集作用明显,其抚育间伐前后根际土全磷和有效磷含量均显著高于非根际土(P<0.05),抚育间伐使千年桐和闽楠根际土全磷和有效磷含量得到显著提高(P<0.05),在0~15 cm土壤深度,随着土壤深度增加,千年桐和闽楠根际土全磷和有效磷含量均呈上升的趋势。2)千年桐不同土壤深度根际土全磷与有效磷含量在抚育间伐前后均高于闽楠,抚育间伐后千年桐与闽楠不同土壤深度根际土全磷含量的差值与有效磷含量的差值均增大,抚育间伐提高了千年桐与闽楠枝、叶、干、根全磷含量,在抚育间伐前后,千年桐枝、叶、干、根全磷含量均高于闽楠。3)相关性分析表明,千年桐和闽楠根际土有效磷与根全磷、叶全磷均为显著正相关(P<0.05),其根全磷与叶全磷也显著正相关(P<0.05)。抚育间伐提高了千年桐和闽楠营养器官与根际土磷含量,对非根际土磷含量影响较小,对千年桐和闽楠根际土壤磷活化吸收有促进影响;抚育间伐对千年桐的影响程度大于闽楠,千年桐根系比闽楠更发达,具有更强的土壤磷活化能力。

The disturbance mechanism of phosphorus dynamic structure by tending cutting in the mixed forest of Vernicia montana and Phoebe bournei was clarified,providing a basis for the scientific management of soil phosphorus in this forest.Total phosphorus and available phosphorus content in soil and total phosphorus in branches,leaves,stems and roots of five year old Vernicia montana and Phoebe bournei from Fanqiao State-owned Forest Farm,Nanping,were determined.The impact of tending cutting on phosphorus content in rhizosphere soil and vegetative organs was studied.The results show that:1)Rhizosphere phosphorus enrichment was evident in both Vernicia montana and Phoebe bournei.Total phosphorus and available phosphorus levels in the rhizosphere soil were significantly higher than in non-rhizosphere soil before and after tending cutting(P<0.05).Tending cutting increased total phosphorus and available phosphorus in the rhizosphere soil(P<0.05).At a depth of 0-15 cm,rhizosphere soil phosphorus levels increased with depth for both species.2)Vernicia montana had higher total phosphorus and available phosphorus in rhizosphere soil at different soil depths compared to Phoebe bournei before and after tending cutting.After tending cutting,both total phosphorus content difference and available phosphorus content difference of rhizosphere soil increased at different soil depths of Vernicia montana and Phoebe bournei.The content of total phosphorus in branches,leaves,stems and roots of Vernicia montana and Phoebe bournei were increased by tending cutting.The content of total phosphorus in branches,leaves,stems and roots of Vernicia montana was higher than that of Phoebe bournei before and after tending cutting.3)Correlation analysis showed a significant positive correlation between available phosphorus in rhizosphere soil and total phosphorus in roots and leaves of Vernicia montana and Phoebe bournei(P<0.05),as wll as a significant positive correlation between total phosphorus in roots and total phosphorus in leaves(P<0.05).Tending cutting increased phosphorus content in vegetative organs and rhizosphere soil,with little effect on non-rhizosphere soil phosphorus.It promotes phosphorus activation and absorption in the rhizosphere soil of both.The effect of tending cutting on Vernicia montana was greater than on Phoebe bournei.The Vernicia montana root system is more developed than that of Phoebe bournei,granting it a stronger ability of soil phosphorus activation.