Abstract:The aim of this paper was to determine the optimum seedling N content and rate of N fertilizer application for Larix olgensis in a field culture experiment conducted with three exponential N fertilization regimes. The treatment that resulted in both the greatest seedling biomass and the highest seedling N content after 111 days of growth applied a total of 30mg N plant-1 at an exponentially increasing rate. This treatment resulted in a average optimum N application rate of 0.29 mg plant-1 d-1 over 103 days of growth. In this treatment, seedling biomass, N content and N uptake efficiency were 637.80 mg plant-1, 8.10 mg N plant-1 and 41.77%, respectively. Based on binomial regression of the biomass and N content growth curves from the three N fertilization treatments, 24.3 to 33.7 mg plant-1 N supplied in 111d resulted in the greatest biomass and highest N efficiency. We conclude that the treatment with 30 mgN plant-1 supplied produced better seedlings than either 60 mgN plant-1 or 70 mgN plant-1 treatments.