Water conservation is an important issue today. In 2005, the average residential water use in the United States was 371 liters capita1 day1 (USGS, 2005). In Utah, water is a limited resource; it’s the second most arid state in the nation, and is prone to droughts. In 2005, the average domestic or residential water use was 971 liters capita-1 day-1, of this, 439 liters capita-1 day-1 was used for watering lawns, plants, and gardens (Utah Division of Water Resources, 2007). Additionally, Utah is one of the fastest growing and most highly urbanized states. Therefore, residential and commercial landscape watering is a large potential source of urban water conservation. Climate-based irrigation controllers, also known as “smart controllers”, have been developed to help conserve water in landscapes with an automatic irrigation system installed. Smart controllers measure weather conditions daily to determine the amount of water plants need and allow irrigation. The main objective of this study was to evaluate, in a landscape setting, whether different climate-based irrigation controllers achieve different levels of water conservation. The experiment took place at Utah State University’s Greenville Research Farm in plots composed of an area of turfgrass (21m2) irrigated with sprinkler heads and another area of ornamental plants (7m2) irrigated with a drip irrigation system. Four experimental treatments with 5 replications were evaluated and arranged in a randomized complete block design. Each treatment represented a different irrigation controller. Hunter® Solar Sync and WeatherMatic® controllers used on-site sensors to measure weather conditions, while Rainbird® ET Manager used a remote paging signal to retrieve weather data from the closest weather station. In addition, standard irrigation controllers were programmed to irrigate control plots with schedules based on historical ETo of the hottest month of the year. Measurements were made during 10-week periods during 2011 and 2012. Data collected and analyzed included weather conditions, weekly and overall water application amounts, distribution uniformity of the irrigation system, irrigation adequacy, and irrigation efficiency. Overall controller performance was analyzed using correlations between irrigation adequacy and efficiency. Results indicated average water savings based on the control treatment of 37, 39.5 and 48% for the Hunter® Solar Sync, Rainbird® ET Manager, and Weathermatic® controllers, respectively. Statistically significant differences in weekly water application indicated that the Weathermatic® controller applied significantly less water than the other treatments; Rainbird® ET Manager and Hunter® Solar Sync were not significantly different from one another. Control plots had significantly higher water applications than the rest of the treatments. Climate-based controllers modified irrigation scheduling based on weather, with noticeable changes during precipitation events. Irrigation efficiency values for all climate-based controllers were significantly higher than the control treatment. In 2011, Weathermatic® controllers had the best performance, followed by Hunter® Solar Sync and Rainbird® ET Manager. In 2012, all climate based-controllers performed significantly better than the control treatment. All of the climate-based controllers evaluated in the study are recommended for use in landscape for improving irrigation efficiency. Additional research that integrates plant health and quality, and evaluations of cost, adaptability, installation, programming and failure events are recommended.
Available at: http://works.bepress.com/kelly_kopp/241/