Earthworm in Toxic and Non-Toxic Endophyte Infected Tall Fescue Pastures in the Ozark Plateau.

The fungal endophyte (Neotyphodium coenophialum Glenn, Bacon and Hanlin) infects tall fescue (Lolium arudinanceum (Schreb.) S.J. Darbysh, E+) and results in the production of alkaloid compounds that improve drought tolerance and resistance to herbivory. Ergot alkaloids have been linked to grazing animal health problems. Naturally occurring endophyte stains that do not produce ergot alkaloids have been used to infect endophyte-free (E-) tall fescue varieties resulting in non-toxic endophyte infected tall fescue varieties (NE+) that retain the benefits of the endophyte-tall fescue relationship without the animal health concerns. Few studies have examined the effects that altered alkaloid concentrations may have on the soil ecosystem. The objective of this study was to evaluate earthworm populations in E+ and NE+ tall fescue pastures. Eight pastures (4 E+ and 4 NE+) were sampled in December of 2007 and March and December of 2008 and 2009. Three 30x30x20 cm volumes of soil were dug out of each field and sorted by hand to extract earthworms. Earthworm abundances were calculated on a per m² basis and averaged per pasture at each sampling time. Populations were greater in the NE+ (398 m^-2) than the E+ (215 m^-2) pastures (LSD 145 m^-2) suggesting that earthworms may benefit from the non-toxic endophyte-tall fescue symbiosis.