Comparison of Athletic Field Performance Assessment Methodologies.

Performance assessments of natural turf athletic fields have been conducted since the 1960’s. The most common characteristics evaluated are surface hardness and soil penetration resistance, which are highly dependent on traffic, soil texture, turfgrass cover, and percent volumetric water content (%VWC). The driving force behind these assessments is to increase the playing quality of the field, thus providing a safer surface for athletic participants. Field managers often use assessment data to adjust management practices that may lead to reductions in resource inputs, labor costs, and environmental impacts. Global Information System (GIS) technology allows for the spatial analysis of edaphic and landscape features across an entire athletic field using interpolation techniques that predict values of unknown areas. The methodology utilized when obtaining field assessments can play an important role in the accuracy of the interpolation. Previous performance testing protocols (American Society for Testing and Material) have been based on assessment of only a few test locations per field (6 to 8 for surface hardness) and rely on the use of hand-held instruments. This can be extremely time consuming, costly, and limited with respect to spatial variability. The Toro Company recently introduced a mobile multi-sensor device, the Precision Sense 6000, which allows for a more time efficient method of collecting hundreds of data points across an entire athletic field. This unit is capable of sampling soil volumetric water content  (10 cm depth), soil salinity by apparent soil electrical conductivity (ECa), soil hardness by penetrometer resistance, plant performance by spectral reflectance (NDVI, normalized difference vegetative index), and topography (slope, aspect); all with GPS labeling. The introduction of a larger sample size increases interpolation accuracy of athletic field characteristics. Surveys were conducted on three soccer fields at a sports complex in Roswell, GA and another in Athens, GA. Each sports complex was considered an experimental run, whereas soccer fields were considered replications within each run. The Toro Precision Sense 6000 unit was used to collect penetration resistance at 1068 locations across each soccer field, while a Trimble GeoExplorer 6000 hand-held GPS was employed to geo-reference penetration resistance readings (7 or 24 locations) obtained with a hand-held penetrometer. ArcGIS software was used to analyze penetration resistance spatial data and create maps allowing for the comparison of methodology accuracy.