Spectral Reflectance Response of Riviera Bermudagrass Under Saline Irrigation.

The availability of water currently is a growing concern throughout the world as it is an increasingly valuable and limited resource. This often requires the use of low quality and effluent irrigation water which is high in salinity. High salinity affects the quality of turfgrasses by causing osmotic pressure from the soil to remove water from the plant leading to rapid wilting and even death. Therefore, it is very important to know how turfgrass responds to various levels of salinity. Bermudagrasses (Cynodon spp.) are the most commonly utilized turfgrasses throughout the southern United States. Riviera is an industry standard and intraspecific hybrid that was developed at Oklahoma State University. The objective of this research was to evaluate the response of Riviera bermudagrass when consecutively irrigated with thirteen salinity levels via manual overhead irrigation for a duration of thirty days. The salinity levels were set to be in increments of 4 ds mˉ¹ ranging from 0-48 dS m-¹. The experiment was conducted in a controlled environment with four replications of each salinity treatment. Every three days, the spectral reflectance response was determined by normalized difference vegetation index (NDVI). The turfgrass was also evaluated for leaf firing (LF) as a visual verification since previous studies have shown a strong correlation between NDVI and LF. Results indicated that significant differences were observed among different salinity treatments. As the salinity level of the irrigation water increased, NDVI and LF decreased. The control maintained a higher LF and NDVI value throughout the experiment. As expected, NDVI and LF were highly correlated with one another (r=0.95). This study provided an accurate depiction of the spectral reflectance responses of salinity on Riviera bermudagrass when exposed to different salinity levels. These findings could lead to the development of a fast, large-scale screening method for identifying more salt tolerant turfgrass cultivars.