Sample analyses
Soil available N and P may alter AM fungal impacts on plant fitness in
native grassland (Johnson, 2010; G. Yang et al., 2016). Therefore, soil
available P and inorganic N in each experimental plot were measured
annually; soil available P was measured through the Olsen method
(Bélanger & Rees, 2007), while soil inorganic N
(NH4+-N and
NO3–-N) was determined by a flow
injection autoanalyser (Flowsys; Ecotech, Germany). Mycorrhizal root
colonisation was assessed using the method described by Trouvelot
(1986)(Trouvelot, 1986). The extra-radical biomass of AM fungi was
measured by soil neutral lipid fatty acid (NLFA) analysis (Andrino,
Guggenberger, Sauheitl, Burkart, & Boy, 2021; Cozzolino, Di Meo, Monda,
Spaccini, & Piccolo, 2016; Stevens et al., 2020).