基于根际微生物关键过程的珍贵固氮树种对退化人工林红壤磷素组分和转化的影响及其调控机制

磷素（P）作为南方红壤地区人工林可持续发展的主要养分限制因子之一，如何提高土壤P的有效性成为当前林业生产中急需解决的问题。申请人在前期研究发现桉树-固氮树种混交林红壤具有更高碳稳定性和氮有效性的基础上，本研究以固氮树种如何调控红壤P转化过程并提高其有效性作为切入点，选择马尾松-格木和桉树-格木混交林作为研究对象，并以纯林作对照，采用野外监测和室内试验相结合的方法，重点探究混交林根际土壤：（1）P组分的时空动态特征；（2）有机磷矿化微生物群落组成与功能的关联性；（3）无机磷活化的解磷微生物类群组成及其驱动因子。通过对上述问题的研究，拟阐明在退化人工林中引入固氮树种后根际土壤P转化的主要调控过程及关键控制因子，旨在从分子、生化以及特定微生物功能群层面上揭示地上植物、土壤、地下微生物之间的耦合关系对P转化过程的影响，为定向调控退化红壤P转化并提高其有效性的人工林可持续经营对策提供科学依据。

Phosphorus (P) is often the key nutrient limiting factor for the sustainable development of plantations in the red soil region of southern China. Therefore, how to improve the availability of soil P has become an urgent problem in forestry production. This project focus on the controlling mechanism of soil P transformation processes and improving its availability which introducing N2-fixing tree species into Pinus massoniana and Eucalyptus plantations. By combining field investigations and laboratory experiments, the objectives of the study are to determine and elucidate (1) the temporal and spatial characteristics of P, (2) the interrelations between soil microbial community and function that associated with organic P mineralization, and (3) the phosphate solubilizing microorganisms and its driving factors of inorganic phosphorus activation in rhizosphere soil. By addressing the abovementioned issues, we aim to elucidate the key factors and operating mechanisms of the interactive controls of the aboveground plants, soil, and belowground microbial communities on P transformation though the level of molecular, biochemistry and specific microbial functional groups. The outcomes of this study are providing the scientific knowledge on the sustainable management strategies of regulating P transformation and improving its availability under degraded soils in south subtropical plantations.