Title: Seasonal Dynamics of Imported Fire Ant Pedoturbation on Soils and Turfgrass in a Mississippi Sod Production Agroecosystem Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 4, 2008
Publication Date: N/A
Technical Abstract: Invasive mound-building imported fire ants (Solenopsis spp.) affect soil quality and crop nutrient management efforts at field and landscape scales. Worker ants actively modify the physical and biogeochemical properties of soil; these alterations are the direct result of nest construction, foraging, colony-wide food sharing, and metabolic functions as well as their influences on biota in the mound soil environment. However, the impact of these soil-inhabiting pests on nutrient levels in turfgrass proximate to mounds as well as the temporal stability of imported fire ant-mediated modifications to soils and turfgrass are poorly understood. The objectives of this pilot study were two-fold: (1) assess seasonal changes in soil parameters and plant nutrients from ant-affected versus undisturbed plots in a warm-season turfgrass agroecosystem (Cynodon dactylon x C. transvaalensis – Tifway 419) at key stages in the ants’ annual nesting cycle; (2) evaluate ant-mediated assimilation/dissimilation effects on soil chemistry and their potential influences on soil processes and surrounding vegetation. Paired soil samples were collected from imported fire ant mounds and proximate control locations (0-5 cm) on 20 September, 18 December 2006, 26 February and 8 June 2007 with paired turfgrass samples (mound versus control) concurrently collected from these sites in September (coinciding with peak annual biomass) and June (peak alate production). Imported fire ant mound soils were significantly higher (P=0.05) in pH, OM, C:N ratios, total C, and Zn. Turfgrass from ant mound perimeters had significantly greater concentrations of N, S, Cu, and Fe compared to undisturbed turfgrass. These ant-mediated effects persisted across seasons. Details of imported fire ant assimilation/dissimilation effects on soil chemistry/processes may reveal avenues for development of better-integrated biological-geochemical control techniques. Results from this study will also help improve remote sensing detection tools useful for identifying and monitoring imported fire ant infestations in high-value turfgrass settings.