Practicability of using Polygonum japonicum as a P accumulator for P phytoextraction from soil amended with swine manure

- P. japonicum showed superior growth and P uptake after swine manure amendment.
- P. japonicum exhibited great P removal potential from swine manure-impacted soil.
- P. japonicum is a promising P accumulator used for phytoextraction.

Phytoextraction is a promising strategy for extracting phosphorus (P) from manure-impacted soil. A pot experiment was performed to evaluate the P accumulation ability and removal potential of Polygonum japonicum during four growth periods (5, 7, 9, 11 weeks) in soil impacted with different concentrations of swine manure (0, 25, 50, 100 g kg−1). A decline was noticed in the biomass of P. japonicum grown in soil with swine manure concentration beyond 50 g kg−1. Plants grown in different concentrations of swine manure showed significantly greater P concentration than that of control. Meanwhile, shoot P concentration was relatively stable at approximately 7-8.5 g kg−1 with a 4-fold increase in manure rate, indicating 25 g kg−1 manure rate was sufficient to cause increase of P uptake. The maximum P accumulation occurred at 11 weeks and was approximately 328 mg plant−1 in shoots and 14 mg plant−1 in roots. Significant increase in P accumulation was observed with the increasing growth periods. The bioaccumulation coefficient was higher than 1, and the translocation rate was over 88%, irrespective of swine manure concentrations. Moreover, the shoot extraction ratio of P. japonicum ranged from 14.05% to 54.18% at 11 weeks. The plant effective number was only 3 and 4 at 50 g kg−1 and 100 g kg−1, respectively. In conclusion, P. japonicum demonstrated great P accumulation ability and removal potential, suggesting that P. japonicum is a potential P accumulator for phytoextraction of excess P.