磷是红壤中植物和微生物生长最重要的限制养分，氮沉降加剧了磷的限制作用。根际是植物和土壤微生物养分竞争最激烈的区域。氮沉降对红壤不同菌根类型人工林根际土壤磷有效性影响机制还不清楚。本研究选择亚热带红壤人工针叶林中的外生菌根(马尾松、湿地松)、丛枝菌根(杉木)植物，采用野外调查、氮添加-根箱培养、13CO2标记-根箱培养控制实验，利用13C-DNA的稳定同位素探针(SIP)、功能基因测序、酶动力学、酶谱监测等技术，分析根际土壤磷有效性、磷酸酶动力学、磷酸酶酶谱、磷酸酶功能基因丰度与种群多样性、13C标记的微生物种群特征等。主要目的：1)揭示红壤外生菌根、丛枝菌根人工林根际土壤磷有效性的影响因素；2)阐明氮沉降对红壤外生菌根与丛枝菌根人工林根际土壤磷有效性影响机制。为氮沉降增加背景下，南方红壤人工林土壤磷维持机制、养分管理提供理论依据。

Phosphorus is the most important limiting nutrient for plant and microbe growth in red soil. Nitrogen deposition increases plant and microbe phosphorus demanding, and rhizosphere is the hot spots of plant-soil microbe nutrient competing area. However, it is not well understood the mechanisms behind nitrogen deposition on rhizospheric soil phosphors availability in ectomycorrhizal and arbuscular mycorrhizal fungal plantation forests in red soil. In this study, we choose ectomycorrhizal fungal (Pinus massoniana, Pinus elliottii) and arbuscular mycorrhizal fungal (Cunninghamia lanceolate) plantation forests in subtropical red soil. By field investigation, nitrogen addition-rhizospheric box planting, 13CO2 labeling-rhizospheric box planting experiments, together with 13C-DNA stable isotope probing, functional gene sequencing, enzyme kinetics, in situ fluorescence zymography techniques, we analyze soil phosphors availability, phosphatase kinetics, phosphatase zymography, phosphatase functional gene abundances and community diversities, 13C lablling microbial diversity, and environmental factors in rhizospheric soils. The major objectives are: 1) to reveal the main affecting factors of rhizospheric soil phosphors availability in ectomycorrhizal and arbuscular mycorrhizal fungal plantation forests; 2) to clarify the mechanisms behind nitrogen deposition on rhizospheric soil phosphors availability in ectomycorrhizal and arbuscular mycorrhizal fungal plantation forests in red soil. This study has significant implications for an understanding of phosphorus maintenance and nutrient management under nitrogen deposition increasing scenario in subtropical red soil plantation forests.