Title: Influences of Imported Fire Ant (Solenopsis spp.) Pedoturbation on Soils and Turfgrass in a Mississippi Sod Production Agroecosystem Authors
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: August 1, 2007
Publication Date: November 4, 2007
Citation: Defauw, S. L., Vogt, J. T., Boykin, D. L. 2007. Influences of Imported Fire Ant (Solenopsis spp.) Pedoturbation on Soils and Turfgrass in a Mississippi Sod Production Agroecosystem. ASA-CSSA-SSSA Annual Meeting Abstracts. Technical Abstract: Invasive mound-building imported fire ants (Solenopsis spp.) actively modify the physical and biogeochemical properties of soil impacting soil quality as well as crop nutrient management efforts at field and landscape scales. Soil alterations result from worker ants’ nest construction and foraging activities, colony-wide food sharing, and metabolic functions. However, influences of these soil-inhabiting pests on nutrient levels in vegetation proximate to mounds are poorly understood. Nutrient concentrations were simultaneously documented for both ant-affected as well as undisturbed soils and warm-season turfgrass (Cynodon dactylon x C. transvaalensis – Tifway 419) from a sod production agroecosystem in the Southern Mississippi Valley Silty Uplands (MLRA 134). Sampling conducted during key phases in the nesting cycle of imported fire ants (IFA) revealed that during late Summer (i.e., IFA biomass maximum), total C, total N, C/N ratios, OM, and Zn concentrations as well as pH of mound soils were significantly higher than control soils; these trends persisted across seasons (Fall to Spring), with one exception (i.e., total N – December). Soil P, K, Ca, Mg, and S concentrations from ant nest soils were substantially higher than undisturbed soils during Fall-Winter. Turfgrass harvested from ant mound perimeters in late Summer exhibited elevated N, P, Ca, S, Cu, Fe, and Na concentrations, whereas ant-affected turf collected the following Spring had substantially higher concentrations of N, K, Mg, S, Cu, Fe, and Zn compared to undisturbed areas. The complexity of biogeochemical interactions within IFA nests was most likely enhanced by plant uptake and excretion in the rhizosphere and seasonal shifts in microbial biomass coupled with continuous soil mixing by colony workers. Further investigation of the intrinsic complexities of soil ecosystem dynamics of IFA nests is warranted. Results from this study may help improve remote sensing detection tools used for identifying and monitoring IFA infestations in high-value turfgrass settings.