*2.3. Data Collection and Statistical Analysis*

The National Turfgrass Evaluation Program (NTEP) standard [18] was used as the guideline to visually assess and rate the turfgrass plots. The NTEP standard ranges from 1 to 9 representing dead and ideal turfgrass, respectively. The visual rating (VR) of six in this study was considered the minimum acceptable quality for residential areas. The visual assessment was done continuously approximately once a week during the trial for a total of 19 times in 2018 and 9 times in 2019. Visual ratings were taken from digital images of each plot. Figure 1 shows the enclosed lightbox used to collect digital images for visual rating. There were borders between the adjacent plots approximately 60 cm wide to avoid interference between them. The data were collected from the center of each plot to eliminate the plot edge effect. A total of 15 soil moisture readings were collected per treatment (5 readings per plot × 3 replications) from the top 12 cm soil layer using a handheld FieldScout TDR 300 Meter (Spectrum Technologies, Inc., Aurora, IL, USA).

The VR and soil moisture data were statistically analyzed using PROC GLIMMIX in SAS 9.4 software package [19]. Each year and species were independently analyzed for the treatment effects as the frequency restrictions and duration of the experiment differed across the years and species. For all the response variables, the fixed effects were the irrigation levels, irrigation frequencies, and the date of data collection. The random effects were block and its interaction with irrigation levels and irrigation frequencies. The treatment effects were considered significant at *p*-values ≤ 0.05. All graphs were created using the plotting software package Veusz 3.3.1 [20].

The daily ETo data were collected from CIMIS station #39, located approximately 170 m away from the experimental site in an adjacent field. The CIMIS ETo data were compared to the estimated ETo data by the smart controller. In addition, the Hargreaves and Samani equation [17] was used to calculate long-term daily ETo for the study site (via the PyETo software package: https://pyeto.readthedocs.io/en/latest/license.html; accessed on 18 August 2021) and compared against CIMIS ETo.

$$ET\_o = 0.0023 R\_d (T + 17.8) \sqrt{TR} \tag{1}$$

where *Ra* is the extraterrestrial radiation (mm day<sup>−</sup>1), *TR* is the difference between the daily maximum and minimum air temperatures (◦C), and *T* is the mean air temperature (◦C).
