Performing Department
(N/A)
Non Technical Summary
The goal of this collaborative proposal is to characterize the overlooked role of ants in no-till agriculture. Ants are ecosystem engineers that define plant and animal communities near their nests. They act aboveground as predators, and belowground by manipulating soil properties. In tropical and subtropical agriculture, their roles have been well defined: they reduce populations of herbivorous insects and weeds and increase soil-nutrient availability. In contrast, the importance of ants is virtually unknown in temperate agricultural systems, like the U.S. Corn Belt. Ants have been largely ignored in this region because historic and ongoing use of tillage limits their abundance and persistence in crop fields. Adoption of no-till farming in some parts of the Corn Belt is providing ants an opportunity to colonize corn and soybean fields and exert their influence on above and belowground function.Our proposal is relevant for the "Pests and Beneficial Species" program because it advances for a key agricultural system knowledge of ants as beneficial species that could improve control of invertebrate pests and weeds while improving soil quality. The ultimate goal of this research is to encourage ant abundance, activity, and function in no-till agriculture to help improve sustainability of crop production.
Animal Health Component
60%
Research Effort Categories
Basic
40%
Applied
60%
Developmental
(N/A)
Goals / Objectives
Objective 1: Define epigeal communities, including ants, present in no-till crop fields and the phenology of key community members.Objective 2: Determine the functional roles of ants in no-till systems.Objective 3: Determine responses of ants to a key agricultural management practice.
Project Methods
To achieve our three objectives, we will conduct a three-year factorial field experiment in PA and IN, which will be led by PI Tooker and co-PI Krupke, respectively, who have substantial experience running field experiments. Co-PIs Suarez and Yannarell will provide key methodological contributions, analyses, and interpretations of the samples we generate in our field experiments. Suarez, an ant ecologist, will assist with ant sampling, identification, gut content analyses, and experimental manipulations. Yannarell, a microbial ecologist, will facilitate soil analyses to understand how microbial communities change with ant activity and function.We will conduct one experiment across four different research farms: two in PA, two in IN, each in different growing regions. In PA, experiments will be in two distinct growing areas, separated by ~200 km: 1) RELARC (~800 ha; Centre Co.) in the Ridge and Valley Province of PA, and 2) Penn State's Southeast Agricultural Research and Extension Center (~120 ha SEAREC, Lancaster County) in the Piedmont Province. The fields in PA will not have been tilled for >20 yr and are typically cover cropped. In IN, we will establish experiments at two Purdue agricultural centers, Northeast Purdue Ag Center (NEPAC; in northeastern IN) and Throckmorton Purdue Ag Center (TPAC; in west-central IN), separated by 190 km and the fields will not have been tilled for >20 yr. Using four locations across the eastern and midwestern portions of the Corn Belt will provide a robust experimental design (8 replicates/state) and provide us with the opportunity analyze our results as one experiment, with state- or site-specific analyses as backup. Moreover, having locations in four growing areas will allow us to capture more of the available variability in ant populations and function, allowing our results to be more generalizable to more of the Corn Belt. To increase the potential to combine data across sites, the fields will have similar soil types. If possible, we will use fields that were recently in alfalfa for ?3 yr to minimize legacy effects. All the farms commonly use seeds coated with NSC, so we will measure neonic residues in each plot at the beginning and end of our 3-yr experiment (pyrethroids are not as persistent). At each location in a 1-ha section of a field, we will establish a 2×2 factorial experiment (4 treatments) in a Latin-square design (4 reps per treatment; 16 plots per site). The two factors will be presence/absence of 1) ants and 2) a winter cover crop. Plots will be 25×25-m to decrease the opportunity for species to move among plots, and we will have 5-m buffers between plots as additional buffers against movement. We will use the core 20×20-m for data collection. While much of our sampling (soil, arthropod communities) will be destructive, the large plot sizes will minimize the influence of sampling, as evidenced by previous work with similar-sized plots that detected treatment influences on epigeal communities and their functioning [21, 34, 92, 93]. Each year plots will occupy the same geo-referenced locations and "footprints" to capture cumulative effects of our treatments over the three-year project