Plant assemblage composition and soil P concentration differentially affect communities of AM and total fungi in a semi-arid grassland.

Klabi, R., Bell, T.H., Hamel, C., Iwaasa, A.D., Schellenberg, M.P., Raies, A., and St. Arnaud, M. (2014). "Plant assemblage composition and soil P concentration differentially affect communities of AM and total fungi in a semi-arid grassland.", FEMS Microbiology Ecology, 91(1: Article number fiu015). doi : 10.1093/femsec/fiu015  Access to full text

Abstract

Adding inorganic P- and N-fixing legumes to semi-arid grasslands can increase forage yield, but soil nutrient concentrations and plant cover may also interact to modify soil fungal populations, impacting short- and long-term forage production. We tested the effect of plant assemblage (seven native grasses, seven native grasses + the domesticated N-fixing legume Medicago sativa, seven native grasses + the native N-fixing legume Dalea purpurea or the introduced grass Bromus biebersteinii + M. sativa) and soil P concentration (addition of 0 or 200 P2O5 kg ha-1 at sowing) on the diversity and community structure of arbuscular mycorrhizal (AM) fungi and total fungi over two consecutive years, using 454-pyrosequencing of 18S rDNA and ITS amplicons. Treatment effects were stronger in the wet year (2008) than the dry year (2009). The presence of an N-fixing legume with native grasses generally increased AM fungal diversity, while the interaction between soil P concentration and plant assemblage modified total fungal community structure in 2008. Excluding interannual variations, which are likely driven by moisture and plant productivity, AM fungal communities in semi-arid grasslands appear to be primarily affected by plant assemblage composition, while the composition of other fungi is more closely linked to soil P.

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