Evaluation of Humic Fertilizers on Kentucky Bluegrass Subjected to Simulated Traffic

Abstract

Sports field traffic tolerance is critical for offering athletes a safe playing surface and adequate turfgrass performance. Humic substances act as bio-stimulants that could enhance turfgrass traffic tolerance by increasing turfgrass efficiency, which could be due to increased root growth, antioxidant activity, and/or physiological health. A two-year field experiment was conducted on a Kentucky bluegrass (Poa pratensis L.) sports field to investigate if incorporating humic substances with fertilizers could improve turfgrass traffic tolerance and performance, and enhance turfgrass recovery after traffic. Treatments included humic-coated urea, poly-coated humic-coated urea, synthetic fertilizer with black gypsum (two application timings), black gypsum, stabilized nitrogen, poly-coated sulfur-coated urea, urea, and a nontreated control. The addition of humic substances to fertilizer treatments did not result in improve traffic tolerance and performance. Fertilizer treatments did not lead to an effect on soil moisture, surface hardness, and shear strength. Turfgrass recovery varied between years. In 2020, the second year of the experiment, four applications of fertilizers increased turfgrass recovery by 136% relative to the nontreated. Furthermore, incorporating humic substances did not result in enhanced turfgrass recovery compared to fertilizers alone. Overall, applications of fertilizers with humic substances could improve turfgrass recovery from traffic compared to fertilizers alone, but results were variable between years.