Natural forests promote phosphorus retention in soil

Soil phosphorus (P) availability often limits plant productivity. Classical theories suggest that total P content declines at the temporal scale of pedogenesis, and ecosystems develop toward the efficient use of scarce P during succession. However, the trajectory of ecosystem P within shorter time scales of succession remains unclear. We analyzed changes to P pools at the early (I), middle (II), and late (III) stages of growth of plantation forests (PFs) and the successional stages of natural forests (NFs) at 1969 sites in China. We found significantly lower P contents at later growth stages compared to earlier ones in the PF (p < .05), but higher contents at late successional stages than in earlier stages in the NF (p < .05). Our results indicate that increasing P demand of natural vegetation during succession, may raise, retain, and accumulate P from deeper soil layers. In contrast, ecosystem P in PF was depleted by the more rapidly increasing demand outpacing the development of a P-efficient system. We advocate for more studies to illuminate the mechanisms for determining the divergent changes, which would improve forest management and avoid the vast degradation of PF ecosystems suffering from the ongoing depletion of P.

Automated summary

The study revealed that phosphorus content significantly decreases in plantation forests as the growth stages progress, whereas it increases in natural forests during successional stages. This suggests that natural vegetation tends to extract phosphorus from deeper soil layers as succession progresses, while plantation forests suffer from rapid phosphorus depletion due to a lack of efficiency in phosphorus use. Further research is needed to understand the mechanisms behind these divergent changes and improve forest management practices to prevent degradation of plantation forest ecosystems.