Growth responses of Canada goldenrod (Solidago canadensis L.) to increased nitrogen supply correlate with bioavailability of insoluble phosphorus source

Anthropogenic nitrogen (N) inputs lead to the increase of phosphorus (P) demand for plants and plant species competition in a N enriched environment may hinge on its ability to utilize soil P sources. In soils, P mostly exists as insoluble phosphate compounds with three mineral elements: iron (Fe), aluminum (Al) or calcium (Ca), and it remains largely unknown whether invasive plant species are able to access such insoluble P sources and its interaction with N enrichment to gain competitive advantage. We determined the morphological traits, growth and nutrient status of an invasive plant Canada goldenrod ( Solidago canadensis L.) cultured in soluble phosphate KH 2 PO 4 (Ortho-P), and insoluble inorganic phosphate AlPO 4 (Al–P), FePO 4 (Fe–P), Ca 5 (OH)(PO 4 ) 3 (Ca–P) at three N supply levels. Results showed that S. canadensis was able to selectively utilize P from Al–P but not from Fe–P or Ca–P by increasing root number and length under N additions. The increasing growth in S. canadensis was closely correlated with the increasing foliar P. Ability to utilize insoluble P sources under enriched N environment serves as a competitive advantage for S. canadensis in Al rich soils. Effective control of S. canadensis invasion may need to consider soil P management in the context of atmospheric N deposition as well.