Objective Explore the effects of different formulations of fertilization on the growth and economic traits of newly planted oil tea forests (young oil tea) and first-fruiting oil tea forests (mature oil tea), and screen the optimal ratios of nitrogen, phosphorus, and potassium as well as the concentration of fertilizers, with the aim of providing theoretical references for further realizing the nutrient management of oil tea forests and scientific fertilization.

Methods Young and mature oil tea forests were used as test objects, and nine different fertilizer formulations were used to treat the soil. Potassium dichromate volumetric method was used to determine the soil organic matter content; Kjeldahl nitrogen method was used to determine the soil total and quick-acting nitrogen content; molybdenum antimony antimony colorimetric method was used to determine the soil total and effective phosphorus content; photon absorption method was used to determine the soil total and quick-acting potassium content; and sulphuric acid-mixed accelerator-distillation method was used to determine the plant's internal elemental content. Distillation method for the determination of elemental content in plants.

Results There were significant differences in soil organic matter, nutrient content and plant elemental content between different treatment groups and the control, and the overall trend was that each trait of the oil tea forest showed an increase and then a decrease with the increase of fertilizer concentration. The young oil tea forest reached the best at treatment group 5, compared with the control group young oil tea forest plant height and diameter increased by 36.6% and 38.7%; mature forest reached the best at treatment group 6, dry kernel yield, yield per plant and oil content increased by 26.4%, 41.7% and 27.5% respectively.

Conclusion The N, P and K ratios of 2:1:1 (N 300 g/plant, P₂O₅ 150 g/plant, K₂O 150 g/plant) in young oil tea forests can effectively promote the growth of plant height and diameter, and the N, P and K ratios of 2:1:2 (N 600 g/plant, P₂O₅ 300 g/plant, K₂O 600 g/plant) in mature oil tea forests can effectively improve the yield and quality of Camellia oleifera.