**5. Conclusions**

Our results suggest that applying typically recommended values of 60% ETo for hybrid bermudagrass and 80% ETo for tall fescue is insufficient to maintain the acceptable quality over high ETo demand months in Central California. The TWRFs fitted to the experimental data suggested 80% ETo as the minimum requirement to maintain the quality of hybrid bermudagrass above the minimum acceptable VR value of 6 for four months (May to August). The TWRFs estimations suggested that applying 100% ETo was sufficient to maintain the tall fescue quality above the threshold for only 50 days. This finding might be an overestimation as tall fescue ratings were negatively affected by minimal fertilizer application in 2019. The Weathermatic controller showed promising results by providing acceptable ETo estimations (5–8% higher than CIMIS ETo) only using onsite temperature measurements. The controller also closely followed programmed watering days restrictions and adjusted the watering days based on ETo demand when no watering restriction was applied. The efficient irrigation scheduling by the smart controller also depends on the accurate calculation of the precipitation rate of the irrigation system, which was substantially underestimated in our study using the widely used catch-cans method. Therefore, researchers should be cautious when using this approach to estimate the precipitation of the irrigation systems.

**Author Contributions:** Conceptualization, A.H.; methodology, A.H.; software, A.H., A.S. (Anish Sapkota), and A.S. (Amninder Singh); validation, A.H., A.S. (Anish Sapkota), and A.S. (Amninder Singh); formal analysis, A.H., M.R., A.S. (Anish Sapkota), and A.S. (Amninder Singh); investigation, A.H., M.R., A.S. (Anish Sapkota), and A.S. (Amninder Singh); resources, A.H. and M.R; data curation, A.H., M.R., A.S. (Anish Sapkota), and A.S. (Amninder Singh); writing—original draft preparation, A.H.; writing—review and editing, A.H., M.R., A.S. (Anish Sapkota), and A.S. (Amninder Singh); visualization, A.H.; supervision, A.H.; project administration, A.H. and M.R.; funding acquisition, A.H. and M.R. All authors have read and agreed to the published version of the manuscript.

**Funding:** This study was supported by the University of California Division of Agriculture and Natural Resources competitive grant (ID#: 17-5021) and the United States Geological Survey (ID#: 2017CA371B).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**

