Understory Plant Functional Types Alter Stoichiometry Correlations between Litter and Soil in Chinese Fir Plantations with N and P Addition

Abstract

Research Highlights: This study identifies the effect of nitrogen (N) and phosphorus (P) addition on stoichiometry correlations between understory plants and soil in subtropical Chinese fir plantations. Background and Objectives: Nitrogen and P are two nutrients limiting forest ecosystem production. To obtain more wood production, N and P are usually applied in plantation management. Changes in soil N and P will generally alter the stoichiometric characteristics of understory plants, which control carbon (C) and nutrient cycles between plants and soil. However, different correlations between plant and soil stoichiometry among functional groups of understory plants have not been investigated, which also impacted element cycling between plants and soil. Materials and Methods: Subtropical Chinese fir plantations were selected for N (100 kg ha−1 year−1) and P (50 kg ha−1 year−1) addition study. We collected fresh litter and the corresponding soil of four understory plants (Lophatherum gracile Brongn., Woodwardia japonica (L.f.) Sm., Dryopteris atrata (Kunze) Ching and Dicranopteris dichotoma (Thunb.) Berhn.) for study of C, N, and P stoichiometric ratios. Results: Nitrogen and P addition affected C, N, and P concentrations and stoichiometric ratios in litter and soil as well as correlations between litter and soil stoichiometric ratios. Understory plant species with different functional types impacted the correlations between plants and soil in C, N, and P stoichiometric ratios, especially correlations between litter C and soil C and N. Conclusions: Changes in soil N and P affect the stoichiometric ratios of understory plants. Functional groups impacted the correlation in C, N, and P stoichiometric ratios between plants and soil, indicating functional groups varied in their impacts on element cycling between plants and soil in plantations with exogenous nutrient addition, which should be considered in future management of plantations with intensive fertilization practice.

Research Progress of Forest Land Nutrient Management in China

“…In addition, nutrient management in forest ecosystems should consider the ecological effects of fertilization under the context of global climate change, considering the potential interactions among global change factors [93,94], nutrient input [95], and internal element cycling within forest ecosystems [96][97][98][99][100][101]. For example, in plantations experiencing intensive management, N input may induce more N leaching due to excessive application, especially in areas characterized by acid soils [101,102].…”

Soil C-N-P pools and stoichiometry as affected by intensive management of camellia oleifera plantations

“…oleifera plantation types also exerted effects on the stoichiometric correlations between C, N, and P via ratios. Changes in N:P ratio indicating potential variations in element limitation for plant growth [ 4 , 8 , 32 ]. In this study, the changes in N:P ratio was not as large as that could be used as index of element limitation [ 8 ], but prolonged study will be necessary to examine the scale of alteration with time.…”

“…Nitrogen and P are the main limiting elements of plant growth in terrestrial ecosystems, their concentration and stoichiometric ratios played important role in plant growth and ecosystem function [33]. In general, soils with N:P ratio lower than fourteen are not able to provide sufficient N for plant growth, while those with N:P ratio above sixteen suggest P limitation [8]. In this study, N:P ratios in both plantation types were lower than seven point five, which indicted potential N limitation for plant growth in the investigated area [4].…”

“…Intensive management will generally enhance biomass accumulation [5], alterations in microbial community compositions [6,7], increases in soil C, N, and P pools [7], and potentially alter the stoichiometric ratios. The stoichiometric ratio of C, N, and P could be influenced by vegetation, soil types, and disturbance [1,8]. In general, the vertical distributions of C, N, and P along soil profiles experience effects of all factors mentioned above via root depth, aeration, soil moisture, fertilization or tillage [9].…”

Biochar Addition Alters C: N: P Stoichiometry in Moss Crust-Soil Continuum in Gurbantünggüt Desert

“…Carbon (C), nitrogen (N), and phosphorus (P), the three most basic elements in soil, play crucial roles in organismic activities [ 1 ]. C is a key building block of structural substances, whereas N and P are the main limiting nutrients for the productivity of terrestrial ecosystems [ 2 , 3 ]. In nutrient-deficient areas, plants need to regulate the stoichiometry of C, N, and P in the plant-soil system to maximize the utilization of soil nutrients in confronting the adverse environment [ 4 ].…”