Leaf–Soil C:N:P Stoichiometry and Homeostasis Characteristics of Plantations in the Yellow River Floodplain in Western Shandong, China

Abstract

The concentrations and ratios of plants C, N, and P serve as important indicators of ecological processes. However, how plant and soil C:N:P relationships and ratios change with forest stand types remain unclear. Here, we analyzed the ecological stoichiometric characteristics by measuring leaf and soil organic C, total N, and P contents in four stand types in Liaocheng, including Populus tomentosa Carrière pure forest, Populus tomentosa–Robinia pseudoacacia L. mixture forests, Platanus orientalis L. pure forest, and Salix matsudana Koidz. pure forests. We find that (1) The N and P leaf contents varied significantly across the four forest stands, with Populus tomentosa–Robinia pseudoacacia mixture forests having higher P levels. Platanus orientalis pure forests had lower C and N but higher P levels compared to others. (2) Uncoupled cycling of P in leaf–soil systems due to environmental influences, but C and N elements showed coupled cycles in some forest stands. (3) Populus tomentosa pure forests, Populus tomentosa–Robinia pseudoacacia mixture forests, Platanus orientalis pure forests are limited by N, and Salix matsudana pure forests are limited by both N and P elements. Overall, environmental factors, in addition to species variations, influence the C, N, P, and C:N:P ratios in leaves and soils of different forest stand types. Enhancing conservation and efficient use of N and P elements is crucial for sustainable plantation forest management to promote optimal growth in the region.