针对亚热带地区不断增加的氮沉降可能改变低磷土壤上林木养分利用策略，且林木不同发育阶段对养分需求策略存在差异，但缺乏这方面系统研究成果现状，以亚热带珍贵阔叶造林树种刨花楠为对象，以多年工作积累建立的同一种源不同发育阶段刨花楠人工林为研究平台，采用林下喷施模拟氮沉降的方法，研究幼龄林、中龄林、近熟林与成熟林四个不同发育阶刨花楠的生长速率、生物量与氮磷养分分配特征；分析叶片与细根氮磷利用性状，厘清菌根共生特征与土壤微生物群落结构关系，阐明氮沉降背景下生长在低磷土壤不同发育阶段刨花楠的生长与氮磷利用规律，揭示氮沉降对刨花楠氮磷利用策略的影响机制，研究结果不仅可以深入认识林木养分利用策略，而且为氮沉降持续加剧背景下刨花楠及相似人工林高效经营与管理（如高效配方施肥技术等）提供理论依据，有助于丰富生长在土壤氮磷养分失衡环境下的植物氮磷化学计量学理论。

The increasing nitrogen (N) deposition in subtropical regions may change the nutrient utilization strategies of trees growing in the soil deficient in phosphorus (P). Besides, trees at their different growth stages demand for N and P nutrients differently. However, little attempt has been made on this issue. Machilus pauhoi, a precious subtropical broad-leaved trees species, will be taken as the study object. Based on years of accumulated work, artificial forests of M. pauhoi in different development stages will be used as research platform. Simulated N deposition experiment, using the understory spraying, will conduct to analyze the growth rate, biomass, N and P allocation characteristics of M. pauhoi at different development stages (i.e. young forest, middle-aged forest, near-mature forest, and mature forest). Then, N and P utilization traits in leaves and roots will be discussed. The relationships between mycorrhizal symbiosis characteristics and soil microbial community structure will also be clarified. The primary objectives of this project are to determine N and P utilization strategies of M. pauhoi in low P soil at different development stages, as well as their response mechanism to N deposition. The results will facilitate a further understanding of nutrient utilization strategies of trees, and also provide a theoretical guidance for discussing the efficient management technology (e.g., high efficiency formulated fertilization technology) of M. pauhoii artificial forest under the increasing N deposition background. It will be also helpful to enrich the stoichiometry theory of plants growing in the soil with unbalanced N and P nutrients.