Characteristics of carbon, nitrogen and phosphorus stoichiometry in the below-ground systems of different stand types of species of Qiongzhuea tumidinoda

The study focuses on the underground systems of four distinct mixed bamboo forests in Mugan Town, Daguan County, Yunnan Province. These include the natural Qiongzhuea tumidinoda - artificial Phellodendri Chinensis mixed forest(T_Q-Rp), the artificial Qiongzhuea tumidinoda - Phellodendri Chinensis mixed forest(R_QP), the natural Qiongzhuea tumidinoda - Broadleaf tree mixed forest(T_QB), and the natural Qiongzhuea tumidinoda - Camellia reticulata mixed forest(T_QC), to compare the differences in carbon(C), nitrogen(N) and phosphorus(P) contents and their stoichiometric ratios of bamboo whips, roots and root and stem. The results showed that the variations of C contents of Qiongzhuea tumidinoda whips, roots and roots of the test stand ranged from 429.00 to 574.20 g/kg, 313.50 to 429.00 g/kg, and 561.00 to 587.40 g/kg, respectively; the variations of N contents ranged from 6.64 to 18.63 g/kg, 1.40 to 11.88 g/kg, and 4.38 to 15.35 g/kg, respectively; and the variations of P contents were from 6.64 to 18.63 g/kg, 1.40 to 11.88 g/kg, and 4.38 to 15.35 g/kg, respectively. 15.35 g/kg; P content varied from 0.44 to 1.00 g/kg, 0.71 to 1.23 g/kg, and 0.42 to 1.15 g/kg, respectively. There was no significant difference in the C content of the underground system of bamboo among the four Qiongzhuea tumidinoda forest types, while the N and P contents were significantly higher in the two artificial mixed forests than in the two natural mixed forests; The average values of C∶N in the underground system of Qiongzhuea tumidinoda are T_QC > T_QB > T_Q-Rp > R_QP in order; The average values of C∶P and N∶P are highest in T_QB, and lowest in R_QP and T_QC, respectively; Except for T_QB, where the growth and development of underground stems of Qiongzhuea tumidinoda are jointly limited by N and P elements, the growth and development of underground stems of Qiongzhuea tumidinoda in other forest types are only limited by N element. The C content, C∶P, and N∶P in the underground system of Qiongzhuea tumidinoda are primarily influenced by organs, followed by the forest stand. The variation in N and P content, as well as C∶N ratio, primarily originates from the forest stand, followed by organs. It is recommended to apply N and P fertilizers reasonably during the cultivation and management process to improve soil nutrient status and enhance plant nutrient utilization efficiency.