Effect of Azospirillum brasilense on Hybrid Bermudagrass Traffic Tolerance

Traffic stress is a major factor limiting the performance, safety and longevity of sports turf systems. The integration of nitrogen (N) fixing bacteria, such as Azospirillum brasilense (AZB), may accelerate post-traffic recovery. A two-year field study (2024–2025) was conducted in Citra, FL, to evaluate the effects of AZB-based commercial products formulations and N fertilization rates on the traffic tolerance and recovery of ‘TifTuf’ Bermudagrass (Cynodon dactylon × C. transvaalensis). Treatments were applied monthly and consisted of three N rates (48.8, 24.4, and 0 kg N ha−1) combined with four AZB treatments (Tazo-B® Liquid, Azopro® Turf, and AzoRoot®, and a non-treated control) arranged in a factorial randomized complete block design. Simulated athletic traffic was applied for five weeks, followed by a four-week recovery period. Turf quality, normalized difference vegetation index, percent green cover, soil moisture and surface hardness were evaluated. AZB products significantly influenced turf performance, particularly when combined with N fertilization. Azopro® Turf and Tazo-B® Liquid improved turf quality and green cover at fertilized N rates. AZB treatments also increased soil moisture, in some cases, reduced surface hardness. Overall, AZB inoculation enhanced Bermudagrass performance under traffic stress and supported acceptable turf quality and recovery at reduced N inputs, suggesting a potential role in reduced-N fertility programs for sports turf management.