Impact of a horticultural mineral oil on bermudagrass performance under salinity stress

Abstract Rising salinity levels in both water and soil pose a pressing challenge for golf course managers throughout the United States. To address this issue, turfgrass managers seek effective products to improve plant health and reduce the impacts of salinity stress. The objective of this study was to evaluate the effects of a mineral oil product on salinity stress in bermudagrass [( Cynodon dactylon (L.) Pers . × Cynodon transvaalensis Burtt Davy), cv. Tifway]. The experiment was conducted in a controlled environment in Stillwater, OK, where bermudagrass was established from sprigs and grown in lysimeters filled with sand. The experimental design was a split‐plot, with irrigation salinity treatment as the main plot factor and the rate of horticultural mineral oil (Civitas Turf Defense Pre‐M1xed; Intelligro) as the sub‐plot factor. Irrigation salinity treatments included three electrical conductivity levels: 1.5, 15, and 30 dS m −1 , and Civitas was applied every 2 weeks at rates of 0, 1.43, and 2.71 mL m −2 . Over 8 weeks, Tifway bermudagrass was evaluated weekly in terms of turf quality, normalized difference vegetation index, vertical shoot growth, and percent green cover. At the end of the study, salt uptake was assessed by measuring the tissue sodium (Na + ) concentration and Na + excretion rate from leaf salt glands. Additionally, root biomass was measured. Results showed a decline in turfgrass performance and an increase in tissue Na⁺ concentration as salinity levels increased. Tifway maintained good quality at 15 dS m −1 for 8 weeks in sand, both without Civitas and with an application rate of 1.43 mL m −2 . However, increasing the application to 2.71 mL m −2 consistently compromised turfgrass performance under 30 dS m −1 salinity stress, highlighting its adverse effects in highly saline conditions.