Poster Number 417
Wednesday, 8 October 2008
George R. Brown Convention Center, Exhibit Hall E
Extensive use of fungicides on golf course to suppress soilborne plant pathogens causing primarily foliar diseases may also lead to reduction of soil microbial activity and the capacity of the soil to cycle nutrients. The objectives of the study were to evaluate the effects of the fungicide tebuconazole at 28.4 grams per 1000 sq ft on soil microbial properties in a field experiment where Zoysiagrass was planted for lawn, yard, or fairway purposes. Soil microbial community was evaluated by total culturable bacterial and fungal populations, bacterial growth strategists, microbial biomass carbon content, and dehydrogenase activity. Applications of tebuconazole resulted in a 28% reduction in fungal counts when compared to non-treated plots. The addition of fungicide alleviated competition between bacteria and fungi, leading to the increase of cultural bacterial counts by 56%. However, the tebuconazole treatment led to the decrease of soil microbial biomass carbon by 19% and dehydrogenase activity by 22%. The application of fungicide led to a shift of microbial community towards enhanced bacterial dominance and favored fast-growing bacteria (r-strategist).