Coupling of different plant functional group, soil, and litter nutrients in a natural secondary mixed forest in the Qinling Mountains, China

Abstract

Soil and litter play important roles in ecosystem nutrient stroage and cycling, which both affect plant growth and ecosystem productivity. However, the potential contributions of soil and litter nutrient characteristics to the nutrient characteristics of different plant functional groups (PFGs) remain unclear.In this study, we investigated the carbon (C), nitrogen (N) and phosphorus (P) concentrations of different organs of three PFGs (trees, shrubs and herbs), litter and soil in nine natural secondary mixed forests in the Qinling Mountains. The results showed that leaves had the highest N and P concentrations and N:P ratios at the organ level, whereas the C:N and C:P values were lowest in leaves. At the PFG level, the N and P concentrations of the same organs in herbaceous plants were signi cantly higher than those in woody species, while the N:P ratio was signi cantly lower in herb leaves than in tree and shrub leaves. Tree organs had signi cantly higher C concentrations and C:N and C:P ratios than shrub and herb organs. The leaf N:P ratios of all PFGs were less than 14, suggested that plant growth was limited by N in the study region. The nutrient contents and stoichiometric ratios in plant organs had different degrees of linkages with those in litter and soil. Soil nutrient characteristics were the main factors affecting the nutrient characteristics of the different PFGs, and litter nutrient characteristics also had important contributions to the nutrient characteristics of PFGs, showing the following order: herbs > trees > shrubs. Our results indicate that the functional difference in plant organs resulted in diverse nutrient concentrations; and varied nutrient connections exist among different ecosystem components. Furthermore, nutrient characteristics of litter and soil can together affect the nutrient characteristics of PFGs.

A Structural Equation Model Suggests That Soil Physical Properties Had the Greatest Negative Influence on the Competition Index of Dominant Trees of Pinus sylvestris var. Mongolia

“…Researchers Burke et al [44] believed that soil is the main nutrient pool for vegetation, and soil physicochemical properties determine the growth and environmental conditions of vegetation and affect the growth and development of interspecific and intraspecific relationships within the plant community. Pang et al [45] studied the relationship between the nutrient characteristics of multiple organs of forest vegetation and soil nutrient characteristics and found that the two are closely related, with soil nutrients contributing 56.4%, 41.4%, and 23.9% to the nutrient characteristics of different life forms of vegetation (trees, shrubs, and grasses), which is similar to the results of our study. According to the SEM analysis, the dominant trees of Pinus sylvestris var.…”

Coordinated Patterns in the Allocation, Composition, and Variability of Multiple Elements Among Organs of Two Desert Shrubs Under Nitrogen Addition and Drought

“…S1, S2), implying a weak coupling between plant and soil nutrient concentrations. The contribution of litter nutrients and environmental factors (e.g., soil moisture, temperature, latitude, and precipitation) might blur the co-variation between plant and soil element concentrations to some extent (Zhao et al 2016;Pang et al 2021;Zhang et al 2021aZhang et al , 2021b.…”