Nutrient contents and ecological stoichiometric characteristics of soil and leaf of Camellia oleifera in Dehong Prefecture, Yunnan Province

Objective Dehong Prefecture in Yunnan Province is the only Camellia oleifera growing area in the northern tropical margin of China. We conducted the study on soil and leaf nutrient content and ecological stoichiometric characteristics of C. oleifera in this area to provide a theoretical basis for scientific fertilization and accurate management of C. oleifera.

Method We determined and analyzed the contents of carbon, nitrogen, phosphorus and potassium in soil and leaves of C. oleifera by ecological stoichiometry.

Result The contents of organic carbon, total nitrogen, total phosphorus and total potassium in C. oleifera forest soil were 47.77, 2.56, 0.69 and 5.28 g·kg⁻¹ respectively, while the contents of available phosphorus and available potassium were 3.69 and 26.05 mg·kg⁻¹ respectively. The changes of organic carbon, total nitrogen and total phosphorus in soil were synergistic; The contents of available potassium and available phosphorus in soil directly depended on the contents of total potassium and total phosphorus. The cotents of carbon, nitrogen, phosphorus and potassium in C. oleifera leaves were 422.09, 13.51, 0.97 and 4.92 g·kg⁻¹ respectively. Nitrogen and phosphorus changed synergistically, and were both regulated by soil phosphorus. The growth and development of C. oleifera was limited by nitrogen and phosphorus, of which phosphorus was the main limiting element. The P and P∶K in leaves showed homeostasis, H_p was 5.08 and H_P:K was 3.26, while the other elements and stoichiometric ratios did not show homeostasis.

Conclusion In order to ensure the health and sustainable production of C. oleifera forest, the input of phosphorus should be continuously strengthened, and the input of nitrogen and potassium should be balanced.