Effects of exponential fertilization on growth and nutrient allocation of Choerospondias axillaris seedlings

<bold>Objective</bold> This study investigates the effects of exponential nitrogen（N）fertilization on the growth and nutrient allocation of <italic>Choerospondias axillari</italic>s seedlings to determine the optimal N application rate，thereby providing a scientific basis for efficient N management in <italic>C. axillaris</italic> cultivation. <bold>Method</bold> One-year-old <italic>C. axillaris</italic> seedlings were subjected to four exponential N fertilization treatments（3，7，11，and 15 g/plant），with an unfertilized control（CK）.Growth parameters including height，ground diameter，biomass，nutrient content，and nutrient accumulation were analyzed. <bold>Result</bold> The seedling height，ground diameter，and biomass initially increased and then declined with increasing N levels，showing significant differences（<italic>P</italic>&lt;0.05）between all N treatments and CK.The maximum values（183.80 cm，25.19 mm，and 329.52 g，respectively）were observed at 11 g/plant，with an increase of 45.47%，106.44%，and 227.36% compared to those of CK.Throughout the growth cycle，N，phosphorus（P），and potassium（K）accumulation followed a “rapid-slow-rapid” trend in response to fertilization.Post-fertilization，root，stem，and leaf nutrient accumulation in N-treated seedlings significantly exceeded CK（<italic>P</italic>&lt;0.05）.Moreover，different nitrogen application level treatments can significantly affect the distribution patterns of nitrogen（N），phosphorus（P），and potassium（K）in various organs of Choerospondias axillaris seedlings.With the increase of nitrogen application level，the distribution ratios of N，P，and K in stems and leaves increase，reaching the optimum at 11 g per plant，while the distribution ratio in roots shows the opposite trend. <bold>Conclusion</bold> Exponential N fertilization can effectively enhance <italic>C. axillaris</italic> seedling growth and nutrient accumulation，with 11 g/plant identified as the optimal rate.