Spatiotemporal variation of site-specific management units on natural turfgrass sports fields during dry down

Abstract

Site-specific management units (SSMUs) are fundamental for the implementation of Precision Turfgrass Management. Short-term spatiotemporal variations of soil compaction and turfgrass vigor may be dynamic during a dry down period on natural turfgrass sports fields. This is due to the inverse relationship between soil compaction and soil moisture/drought stress, which may impact SSMU delineation and identification of site-specific deficient areas within a field. The spatiotemporal change of soil moisture, soil compaction, and turfgrass vigor SSMUs [as measured by volumetric water content (VWC), penetration resistance, and normalized difference vegetative index (NDVI)] were evaluated three times during a dry down from rainfall on native soil and sand capped natural turfgrass sports fields. The relationship of penetration resistance and NDVI with VWC was strongest and only significant on the native soil field during the dry down period. In general, as the fields dried, the magnitude of VWC SSMUs and NDVI SSMUs decreased, while the magnitude of penetration resistance SSMUs increased. This phenomenon was more drastic on the native soil field. Significant changes in spatial distributions were observed for VWC SSMUs and penetration resistance SSMUs on the native soil field; however, minimal changes were reported on the sand capped field. The spatial distributions of NDVI SSMUs were minimal on both fields. It is concluded that short-term spatiotemporal variations of SSMUs on sports fields during a dry down can be significant and considerations should be made prior to sampling based on the objective.