Research Report
Quantifying the Water Movement and Leachate Nutrient Composition of a Sand-Based Athletic Field Virginia Tech Researchers: Ben Kraemer, Student; Mike Goatley, Ph.D., Professor and Turfgrass Extension Specialist; Erik Ervin, Ph.D., Professor of Turfgrass Culture & Physiology; Whitnee Askew, Laboratory Specialist (Crop & Soil Environmental Sciences Dept.); Brian Benham, Ph.D., Associate Professor and Extension Specialist; Laura Lehmann, Environmental/Agricultural Research Manager (Biological Systems Engineering); and Stephen Schoenholtz, Ph.D., Director, Water Resources Research Center Research Sponsors: Virginia Agricultural Experiment Station and Virginia Turfgrass Foundation
The
primary goal of the project is to quantify the nutrient content of leachate leaving sand-based athletic fields through subsurface drainage lines. To accomplish this goal, we are collecting water samples from drainage lines beneath the University of Virginia’s Scott Stadium, using an ISCO automatic water sampler. Once samples
Inside the ISCO.
have been collected, the next step is to have them analyzed to determine the amount of dissolved nitrate and phosphate present in the leachate. Tests will also be performed to determine the physical and chemical composition of the soil at Scott Stadium.
Water sampling
Aside from collecting and storing water samples, the ISCO sampler is also capable of monitoring the amount of water flowing through the drainage system over time. Since its installation at Scott Field in 2011, the ISCO has been creating flow charts that trace the spikes in water content that occur during storm and irrigation events. By studying the flow charts and precipitation records, we have identified certain flow rates to be associated with small storms, large storms and typical irrigation applications. The flow rates are then used to formulate the ISCO’s sampling programs. The ISCO is capable of running up to five different programs, allowing us to install different programs for large storms, small storms and irrigation events. The primary differences between programs are (1) the flow level that initiates sampling and (2) the time interval between samples. Adjusting these variables allows us to accomplish the main goal of sampling, which is to catch as much of the event as possible, especially the peak in flow.
Soil analysis
The purpose of the soil tests is to determine the physical and chemical composition of the rootzone. By identifying how much carbon, nitrogen and phosphorous is currently present, as well as physical characteristics (such as infiltration capacity and bulk density), we will be able to better understand the dynamics of water and nutrient movement through the soil. Having a sound understanding of the field’s soil characteristics will also allow us to more accurately identify connections between management practices and their impacts on the nutrient content of leachate leaving the field. 18 | Virginia Turfgrass Journal May/June 2014