Search Results

Bermudagrass is a warm-season turfgrass species widely used for sports fields, home lawns, and golf courses. Ultradwarf bermudagrass has been used for golf course greens, but its quality declines with abiotic stresses. This 2-year study was designed to investigate if foliar applications of seaweed extract-based biostimulant Utilize® could improve ultradwarf bermudagrass photosynthetic function, nitrate reductase activity, root growth, and root function while under heat stress and drought stress conditions. Utilize® was applied to ultradwarf bermudagrass canopy at 0, 88, 117, 175, and 234 μL⋅m⁻². Two weeks after the initial application of Utilize®, bermudagrass was subjected to heat (40/36 °C, day/night) and drought stress (40–50% evapotranspiration replacement) for up to 42 days. Heat stress and drought stress caused decline of the turf quality. Foliar application of Utilize® at 117, 175, and 234 μL⋅m⁻² biweekly consistently improved turf quality and leaf color ratings and increased leaf chlorophyll and carotenoid concentrations, net photosynthetic rate, nitrate reductase activity, and root growth and viability. On average, Utilize® at 117, 175, and 234 μL⋅m⁻² increased turf quality ratings by 9.1%, 12.1%, and 10.6%, respectively, net photosynthetic rates by 32.4%, 45.0%, and 35.0%, respectively, and nitrate reductase activity by 16.7%, 18.8%, and 14.6%, respectively, compared with the control. Utilize® at 117, 175, and 234 μL⋅m⁻² increased the root biomass, root length, surface area, and root volume compared with the control. Utilize® at 88, 117, 175, and 234 μL⋅m⁻² increased root viability by 46.2%, 73.1%, 88.5%, and 74.4%, respectively, relative to the control. The results of this study suggest that seaweed extract-based biostimulant Utilize® improves nitrogen metabolism, photosynthetic function, root growth, and root viability. Foliar application of Utilize® at rates between 117 and 175 μL⋅m⁻² biweekly can be considered an effective approach to improving ultradwarf bermudagrass performance under heat stress and drought stress environments.

Creeping bentgrass (Agrostis stolonifera) experiences quality decline during summer in the United States transition zone and warmer regions. Various bioproducts have been used to improve creeping bentgrass performance and to mitigate effects of summer stress in the United States transition zone. This 2-year study was carried out to examine if foliar application of seaweed extract (SWE; Ascophyllum nodosum)-based biostimulant Utilize^® could enhance creeping bentgrass nitrate reductase (NaR) activity, and root viability under heat and drought stress conditions. The Utilize^® was sprayed biweekly on creeping bentgrass foliage at 0, 29, 58, 87, and 116 µL⋅m⁻², with application volume of 815 L⋅ha⁻². Two weeks after first application, plants were exposed to heat (35/25 °C, day/night) and drought stress (40% to 50% evapotranspiration replacement) conditions for 42 days in an environment-controlled growth chamber. In general, the abiotic stress caused turf quality reduction. Foliar application of Utilize^® at 58, 87, and 116 µL⋅m⁻² increased turf quality, leaf color ratings, leaf chlorophyll, carotenoid content, and net photosynthetic rate (Pn). Utilize^® at 58, 87, and 116 µL⋅m⁻² increased NaR activity by 26.5%, 16.3%, and 16.3%, respectively, when compared with the control. Utilize^® at 58, 87, and 116 µL⋅m⁻² increased root biomass, root length, surface area (SA), and root volume when compared with the control. Utilize^® at 58 and 87 µL⋅m⁻² improved root viability by 16.3% and 30.9%, respectively, when compared with the control. Our data indicate that the SWE-based biostimulant Utilize^® improves nitrogen (N) metabolism and root viability. Utilize^® treatment at 58 µL⋅m⁻² biweekly can be considered an effective approach for improving creeping bentgrass performance during summer stress.