Seasonal effect of the exotic invasive plant Solidago gigantea on soil pH and P fractions Herr, C. /Chapuis Lardy, Lydie Dassonville, N. Vanderhoeven, S. Meerts, P. exotic species effects Early Goldenrod soil plant P cycling soil phosphorus availability microbial biomass P phosphomonoesterase Invasions by alien plants can alter biogeochemical cycles in recipient ecosystems. We test if Early Goldenrod (Solidago gigantea) alters P fractions. To that end, we compare invaded plots and adjacent, uninvaded resident vegetation for specific fractions of organic and inorganic P, phosphomonoesterase (PME) activity in topsoil, and immobilization of P in above- and belowground organs and in soil microbial biomass. Invaded plots had lower soil pH and 20%-30% higher labile P fractions (resin-P-i, bicarb-P-i, NaOH-Pi), and the difference was consistent across seasons. There was no difference in microbial P. Alkaline-PME activity was 30% lower in topsoil of invaded plots. Annual P uptake in aboveground phytomass was not markedly higher in Solidago. In contrast, P in belowground organs steadily increased in autumn in invaded plots, due to both increased biomass and increased P concentrations. This indicated higher net P immobilization in Solidago, far in excess of both resorption from senescing shoots and P requirements for aboveground biomass in subsequent year. Higher turnover rates of P in belowground organs and mobilization of sparingly soluble P forms through rhizosphere acidification may be involved in the observed differences in soil P status between invaded and uninvaded plots. 2007 text https://www.documentation.ird.fr/hor/PAR00002355 PAR00002355 Herr C., Chapuis Lardy Lydie, Dassonville N., Vanderhoeven S., Meerts P.. Seasonal effect of the exotic invasive plant Solidago gigantea on soil pH and P fractions. 2007, 170 (6), 729-738 EN