Human activities accelerate global nitrogen (N) deposition, and elevated N availability may alter the stoichiometric balance of nutrients and then affect nutrient absorption by plants. The boreal forest is considered one of the world’s most N-limited ecosystems, and its response to N deposition is already a hot issue. In order to explore how long-term nitrogen addition influences nutrient uptake and distribution in Larix gmelinii in a boreal forest, four N treatment levels (0, 25, 50 and 75 kg N ha⁻¹ yr⁻¹) have been applied in a boreal forest since May 2011. Nitrogen addition significantly reduced the soil pH, significantly changed the soil N availability, increased the total N and N/P in needles and fine roots, and decreased the total P in needles and the C/N in soil. Nitrogen addition significantly reduced nitrogen resorption efficiency, and its impacts on P resorption efficiency were not significant. Nitrogen addition significantly increased the root length, surface area and diameter of 4th- and 5th-order transport fine roots. The N and N/P of needles showed seasonal variation. The needle N concentration and N/P were positively correlated with N addition, while the needle P was negatively correlated with nitrogen addition. With increase in nitrogen addition, Larix gmelinii increased its investment in its belowground parts, which may explain why Larix gmelinii tended to put more C in long-lived roots to improve its C utilization efficiency. Given the P deficiency caused by N addition, Larix gmelinii may be more likely to absorb P from the soil and adjust its C distribution to meet its P demand rather than relying on internal nutrient resorption.

人类活动会加速全球氮（N）的沉积，氮的有效利用可能会改变养分的化学计量平衡，进而影响植物对养分的吸收。北方森林被认为是世界上氮素含量最高的生态系统之一，其对氮素沉积的反应已经成为热点。为了探索长期氮素添加如何影响北方森林中落叶松的养分吸收和分布，对四个氮素处理水平（0、25、50和75 kg N ha ^-1  yr ^-1）自2011年5月起已在北方森林中使用。氮的添加显着降低了土壤的pH值，显着改变了土壤的氮素有效性，增加了针叶和细根的总氮和氮/磷，降低了针叶和细根的总磷土壤中的碳/氮。氮的添加显着降低了氮的吸收效率，并且其对磷吸收效率的影响并不显着。氮的添加显着增加了4级和5级运输细根的根长，表面积和直径。针的N和N / P显示季节性变化。针头氮浓度和N / P与氮添加呈正相关，而针头P与氮添加呈负相关。随着氮添加量的增加，落叶松增加了对地下部分的投资，这也许可以解释为什么落叶松（Larix gmelinii）倾向于在长寿根中添加更多的C以提高C的利用效率。考虑到氮的添加导致磷缺乏，落叶松可能更可能从土壤吸收磷并调整其碳分布以满足磷需求，而不是依靠内部养分吸收。