Objective  Growth promotion and adaptability enhancement of Bambusa tuldoides on coastal sandy land in Fujian by application of biochar and nitrogen fertilizer were evaluated.

  Method  Four-year-oldB. tuldoides plants obtained from the Chishan Mountain Farm were used in a 3 factors 3 levels orthogonal experimentation with variables that included applying biochar of different types (A), biochar in different amounts (B), and nitrogen fertilization (C). Calorific value of leaves (AFCV), cost of unit area of biomass (CCarea), and adaptability of the plants were the criteria for economic evaluation and fertilization selection.

  Result   The combined use of biochar and nitrogen fertilizer in cultivating B. tuldoides significantly elevated the carbon, nitrogen, AFCV, cost, and yield of the tree leaves. Treatment No. 5, which applied wheat straw biochar at 400g·plant⁻¹ along with a nitrogen fertilizer at 900g·plant⁻¹, rosed the carbon content in leaves by 28.83%, the number of bamboo shoots by 106.38%, and the CCarea by 50.07%, while lowered the ash content (AC) by 67.63%, over control. In addition, it achieved the highest AFCV among all treatments. An extremely significant correlation was found between the biomass cost and AFCV or carbon content (p＜0.01), whereas a significant negative correlation between that and nitrogen or AC (p＜0.05). Nitrogen fertilization was the primary factor affecting the cost of B. tuldoides biomass.

  Conclusion  Treatment No. 5, which combined the applications of 400g of wheat biochar and 900g of nitrogen fertilizer per plant, significantly enhanced the leaf growth, biomass production, and plant adaptability of B. tuldoides. It was considered the choice fertilization for building the ecologically beneficial forest on the coastal sandy land in the province.