Poster Number 201
See more from this Division: S03 Soil Biology & BiochemistrySee more from this Session: General Soil Biology & Biochemistry: II
Here we report the effect of three symbiont fungal genotypes on plant community composition and trace gas fluxes of tall fescue stands over a one year study period. For one variety of tall fescue (PDF, Noble Foundation), we had plots of common toxic endophyte infected (CTE+), two novel endophyte genotypes (AR-542, AR-584) infected, endophyte free (E-), and a mixture of all of endophyte statuses together (MIX). Tall fescue cover and total grass biomass were significantly lower in E- than CTE+, AR-542, AR-584 and MIX, but no significant differences among endophyte genotypes and/or MIX were found. Forb biomass cover and plant species richness were greatest in E- plots, lowest in CTE+, and intermediate for AR-542, AR-584, and MIX plots. All of these plant community effects were strongly seasonal and were more significant in fall than spring.
Endophyte genotype also significantly influenced soil CO2 and N2O flux, as higher fluxes were observed from AR-542 compared to the other treatments. Soil NH3 volatilization was affected by endophyte presence but not by endophyte genotype. Significantly higher soil NO3--N contents were found from AR-584 than rest of treatments. However, soil NH4+-N concentration was not influenced by endophyte presence or genotype. In summary, fungal endophyte presence and genotype significantly affected tall fescue pasture species richness, grass biomass, and soil trace gas fluxes, suggesting that endophyte identity is important in understanding the ecosystem-scale effects of this agronomically important grass-fungal symbiosis.
See more from this Session: General Soil Biology & Biochemistry: II