Effects of Long-Term Fertilization and Stand Age on Root Nutrient Acquisition and Leaf Nutrient Resorption of .

The plant nutrient acquisition strategies are diverse, such as root nutrient acquisition and leaf nutrient resorption, playing important roles in driving soil processes, vegetation performance as well as ecosystem nutrient cycling. However, it is still in a debate whether there is a synergy or tradeoff between above- and below-ground nutrient acquisition strategy under nitrogen (N) and phosphorus (P) addition, or with stand age. Herein, this study investigated the responses of root-soil accumulation factor () and leaf nutrient resorption efficiency () to long-term N and P fertilization, and further explored the trade-off between them in plantations with different stand age. Results showed that under N fertilization in young plantations, leaf N resorption efficiency () increased, and root-soil accumulation factor for P () decreased. For young forests under P fertilization, the increased whereas decreased. For middle-aged forests under P fertilization, the and leaf P resorption efficiency () increased and the decreased. Under P fertilization in young and middle-aged plantations, had a significant positive correlation with . Under N fertilization in young plantations, was significantly positive correlated with root-soil accumulation factor for N (). The covariance-based structural equation modeling (CB-SEM) analysis indicated that stand age had positive effects on whether under N or P fertilization, as well as on under N fertilization, whereas had no effects on the or Overall, our results can shed light on the nutrient acquisition strategies of plantations under future environmental changes and the results could be applied to the nutrient management practices.