Shifts in soil nutrient concentrations and C:N:P stoichiometry during long-term natural vegetation restoration

Abstract

Background Ecological stoichiometry (C:N:P ratios) in soil is an important indicator of the elemental balance in ecological interactions and processes. Long-term natural vegetation plays an important role in the accumulation and distribution of soil stoichiometry. However, information about the effects of long-term secondary forest succession on soil stoichiometry along a deep soil profile is still limited. Methods We selected Ziwuling secondary succession forest developed from farmland as the study area, investigated the concentrations and stoichiometry of soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) at a depth of 0–100 cm along a 90-year succession chronosequence, including farmland (control), grassland, shrub, early forest, and climax forest. Results SOC and TN concentrations significantly increased with increasing restoration age, whereas soil P concentration remained relatively stable across various successional stages. SOC and TN concentrations decreased with an increase in soil depth, exhibiting distinct soil nutrient “surface-aggregation” (high nutrients concentration in the top soil layer). The soil C:P and N:P ratios increased with an increase in restoration age, whereas the variation of the C:N ratio was small and relatively stable across vegetation succession. The nutrient limitation changed along with vegetation succession, transitioning from limited N in the earlier successional stages to limited P in the later successional stages. Conclusion Our results suggest that more nitrogen input should be applied to earlier succession stages, and more phosphorus input should be utilized in later succession stages in order to address limited availability of these elements. In general, natural vegetation restoration was an ecologically beneficial practice for the recovery of degraded soils in this area. The findings of this study strengthen our understanding of the changes of soil nutrient concentration and nutrient limitation after vegetation restoration, and provide a simple guideline for future vegetation restoration and reconstruction efforts on the Loess Plateau.

Characteristics of Soil Nutrients and Their Ecological Stoichiometry in Different Land Use Types in the Nianchu River Basin

“…Under all land-use types, the topsoil layer (0-10 cm) had the highest levels of SOM, N, and P. As nutrients such as SOM and N generally accumulate in the soil's surface layer [30], microbially driven apoplast decomposition primarily occurs in the surface soil [14], increasing nutrient concentrations in the surface soil. Organic matter input decreases with increases in soil depth due to microbial decomposition activity and reduced root secretion [44]. In this study, there was no significant change in TP content with increasing soil depth for the four land-use types.…”

Vertical root distribution and biomass allocation along proglacial chronosequences in Central Switzerland

“…Our findings suggest that vegetation of young moraines is adapted to sites with limiting resources because of the potential to exploit larger volumes of soil (Gale and Grigal 1987). We further assume that late successional vegetation develops shallow root systems to exploit the resources that are concentrated in the upper soil layers as a result of biocycling and soil development (Gale and Grigal 1987;Gao et al 2014;Ma et al 2020). The vertical root distribution coefficients β of this study covered a wide range of values compared to a great variety of biomes, from tundra ecosystems to sclerophyllous shrublands (Jackson et al 1996).…”

Heavy metal pollution assessment and soil property evolution under a natural ecological restoration process in a manganese wasteland in China

“…In general, the results of this study showed that soil nutrient levels increased over the restoration period. Among various soil parameters, soil C, N, and P (Ma et al 2020), macrometallic nutrients (Nyenda et al 2021) and enzymes (Sun et al 2021) are often considered.…”

“…There are some common methods used to assess soil properties. For example, the total nitrogen (TN), total phosphate (TP) and soil organic matter (SOM) levels are always considered in the assessment of nutrient status (Chen et al 2007; Ma et al 2020). The single‐factor index ( P i ) (Li et al 2007; Liu et al 2020 b ), Nemerow index ( P com ) (Liu et al 2018; Liu et al 2020 b )), monomial potential ecological risk factor ( R i ) (Hakanson 1980; Liu et al 2020 b ), potential ecological risk index (RI) (Hakanson 1980; Liu et al 2020 b ), etc., are commonly used to evaluate soil HM pollution (Kowalska et al 2018; Liu et al 2020 b ).…”