Effect of grass species and fungal endophyte on soil nitrification potential

Abstract

This experiment tested the impact of grass species and fungal endophyte status and strain on soil nitrification. Three C3 grass–endophyte combinations were tested: Festuca arundinacea–Neotyphodium coenophialum; F. pratensis–N. uncinatum; Lolium perenne–N. lolii, and included different strains of endophyte and endophyte-free grasses. Three C4 species— Brachiaria decumbens, Paspalum dilatatum and Pennisetum clandestinum—of unknown Acremonium endophyte status, were also tested. Plants were grown for 6 weeks without fertiliser in pots in a field soil (Mollic Psammaquent), then rhizosphere soil was sampled and incubated at 27 °C with and without (NH₄)₂SO₄. The –N production was measured weekly. The presence of plants significantly increased the nitrification rate compared with bare soil. There were significant differences (P=0.02) among plant species. In all cases, endophyte presence increased nitrification in soil samples (P<0.001) relative to endophyte-free within a species.