Bedrock determines the elevational patterns of soil phosphorus pools in
a subtropical karst forest
Abstract
Soil phosphorus (P) is an important nutrient limiting plant
productivity. The elevational pattern of soil P concentrations is widely
used to indicate how P pools are affected by the climate. Despite
previous research finding various patterns of soil P concentration
across different elevations, little research has been conducted on how
bedrock variation in an elevational transect affects P pools. In this
study, we examined the elevational patterns of soil P pools (e.g.,
labile inorganic P (Pi) and organic P (Po), moderately labile Pi and Po,
primary mineral P, and occluded P) in top-soils in an elevational
transect with alternating bedrock types of clasolite and limestone in a
subtropical karst forest. The results showed that concentrations of soil
total P, labile Pi, primary P, and occluded P were significantly higher
in limestone soils than clasolite soils, while there were no significant
differences in labile Po, moderately labile Pi and Po concentrations
between the two bedrocks. There were generally no significant linear
elevational trends for soil P pools. Our results revealed that the
bedrock type had a greater influence on soil P pools than climatic
factors. Our study emphasizes the importance of using bedrock changes as
a driving factor for the spatial distribution of soil phosphorus pools
in mountainous ecosystems.