Effects of the light intensity of LEDs on the growth and physiological characteristics of tall fescue

To determine the optimal conditions for cultivating high-quality lawn under suitable light intensity using an LED light source, the effects of different light intensities on the morphology, physiological characteristics and power utilization efficiency of tall fescue were studied. To this end, tall fescue variety ‘Battle 4’ was used as the test material, with light intensity treatments of 100 (L₁₀₀), 150 (L₁₅₀), 200 (L₂₀₀), 250 (L₂₅₀), 300 (L₃₀₀), and 350 (L₃₅₀) μmol·(m²·s)⁻¹ under a red and blue LED light source. The results showed that when the light intensity was lower than 200 μmol·(m²·s)⁻¹, the morphology, nutrient accumulation, and antioxidant capacity of tall fescue was significantly inhibited. As the light intensity increased, the normalized difference vegetation index (NDVI) and color of tall fescue gradually increased. In addition, root growth became stronger, which is conducive to biomass accumulation and the antioxidant capacity of tall fescue. However, when the light intensity was increased to 300 μmol·(m²·s)⁻¹, the effect of light intensity on the growth of tall fescue was weakened. The high power utilization efficiency of using LED cultivation was significantly lower in L₃₅₀ processing than that of L₁₀₀, L₁₅₀, and L₃₀₀. Regression analysis indicated that the normalized vegetation index of tall fescue was highest at a light intensity of 291.25 μmol·(m²·s)⁻¹ close to 300 μmol·(m²·s)⁻¹. These results suggest that a light intensity of 300 μmol·(m²·s)⁻¹ is sufficient to ensure the normal growth of tall fescue and maintain high turf quality while reducing energy consumption.