Is Phytoextraction Efficient for Remediating Phosphorus-Enriched Soils in Mountainous Region? A Case Study of Lake Dianchi Watershed of Southwestern China

Phosphorus leakage from phosphorus-enriched soils (PES) is a major cause of water degradation worldwide, and phytoextraction is known to be an effective method of remediation. However, it is unclear whether phytoextraction is equally efficient in mountainous regions. We investigated the potential of P accumulation of major plant species in the Lake Dianchi Watershed of Southwestern China. Most of the plants living in PES of this region have high P contents; some have been identified as P-hyperaccumulators, such as Polygonum pubescens, which has the highest leaf P content of 16.88 mg/g. Although the dominate species have relatively low P contents than the P-hyperaccumulators, they still have a higher P uptake potential due to their greater biomass, for example, the P uptake potentials of Alnus nepalensis, Coriaria nepalensis, and Erianthus rufipilus are 46.98, 16.91, and 22.78 kg/ha, respectively. While these plants can decrease the total P of rhizospheric soil and topsoil, the effects on the total P-pool was not significant. Our results suggest that just phytoextraction may be less efficient in remediating PES in mountainous regions, and it requires further studies about P cycling and native plants to design more effective measures for P immobilization.