2025 Volume 53 Issue 2 Pages 79-84
The objective of this indoor growth experiment was to ascertain the standard value of daily integrated light required for the growth of TifGrand under trampling pressure conditions. The experiment was conducted under temperature and humidity conditions that simulated the months of June and October, when poor growth due to lack of sunlight is known to occur in Tokyo. Given that TifGrand demonstrated a proclivity to reach its zenith at NDVI of approximately 0.8, it was postulated that NDVI of 0.8 would not precipitate aboveground turfgrass quality defects due to inadequate illumination. It was therefore inferred that this value represents the minimum daily integrated light intensity required for optimal aboveground turfgrass quality of TifGrand in the context of this study. In contrast, the dry weight of TifGrand demonstrated a tendency to increase with elevated daily integrated light intensity, which was not observed in NDVI. It is therefore proposed that efforts to optimize stadium design, with the objective of maximizing sunlight reaching the turf and the use of supplemental lighting, may contribute to improved turfgrass quality. In the present experiment, the condition of daily integrated light intensity reaching NDVI of 0.8 was identified as the reference value required to maintain good aboveground turfgrass quality. However, further investigation is necessary to examine whether the turfgrass quality can be used as a sports turf, by looking at the actual quality and utilization of the turf on the ground.
