The possibility of visualizing the diagnosis of growth and growth disorders of Hybrid Bermuda Grass (Cynodon dactylon×C. transvaalensis)

Abstract

Sports turfs are used for athletic sports. The leaf blades, upright stems, and root systems of a sports turf can be severely damaged by sporting activities. This study was carried out on a sports turf consisting of Hybrid Bermuda Grass (Cynodon dactylon×Cynodon transvaalensis). To visualize the growth and growth disorders of this turf, we monitored it between August 25 and October 3, 2021. We determined parameters such as leaf color change (L^＊a^＊b^＊), indicating chlorophyll amount (SPAD value), normalized difference vegetation index (NDVI), green leaf area ratio (trimerization method), and turfgrass and soil surface hardness (Yamanaka method) at different treading stresses to assess and relate them with growth activity. We analyzed the relevance and relationships between these results and tested their potential for the diagnosis and visualization of the growth of grass on the turf. (1) Whether the hardness of the surface of the growth of turfgrass increased due to the increase in the intensity of treading stress could not be confirmed. It is evident that the leaf blades and stems of the Hybrid Bermuda Grass turf relieve treading stress. (2) The NDVI value decreased as the intensity of treading stress increased, indicating an increase of dead leaves and damaged foliage. (3) The SPAD value, which indicates of chlorophyll amount, also decreased as the NDVI value decreased. (4) The hue angle of the foliage color changed from green to yellowish green as the intensity treading stress increased. These results possibly show the visualization and quantification of the growth disorder of the Hybrid Bermuda Grass turf caused by the increase in the intensity of treading stress. Measurements will be continuously performed in the future for a better diagnostic analysis.