Sensor-Based Control of Irrigation in Bermudagrass

Abstract

Irrigation water use represents a substantial opportunity for residential water savings. Automation of irrigation systems, based on soil moisture sensors (SMSs), has the potential to provide maximum water use efficiency by maintaining soil moisture at optimum levels. The objectives of this experiment were to quantify differences in irrigation water use and turf quality between: 1) a SMS-based irrigation system compared to a completely time-based scheduling, 2) different commercial irrigation SMSs, and 3) a completely time-based scheduling system with or without a rain sensor. The experimental area consists of common bermudagrass (Cynodon dactylon L.), located in Gainesville, Florida. Four quarter-circle pop-up sprinklers, in a square with 3.66 m sides, irrigated each of 64 plots, distributed in a completely randomized design. Treatments consisted of irrigating one, two, or seven days a week. Each of these schedules compared four different commercial SMSs brands. These SMSs may interrupt scheduled irrigation cycles, depending on the soil moisture status. Other treatments compared plots with or without a rain sensor. A non-irrigated treatment was also implemented. No significant differences in turfgrass quality among treatments were detected, which was evidenced by good quality in non-irrigated plots. Treatment without-rain-sensor used 45% 269-429-0300 (2950 Niles Road, St. Joseph, MI 49085-9659 USA). more water than the with-rain-sensor treatment. Not all SMSs tested performed the same. Sensors from brand A recorded irrigation water savings ranging from 59% to 88%, brand B from 73% to 82%, and brand D from 46% to 81%, depending on the scheduled irrigation frequency. Brand C showed water savings only within a 1-day/week frequency.

Overview of emerging technologies in sprinkler irrigation to optimize crop production

“…There are several ways to improve the water distribution of sprinklers under a low pressure. For example, an orifice nozzle, non-circular nozzles, vanes and fluidic devices can be installed on these sprinklers [30,31] . Li et al developed a fluidic sprinkler based on the principle of "coanda effect" where water flows from the nozzle into a tube installed in the fluidic component to form low pressure area [32] .…”

“…(1) Rain sensor: A rain sensor is an irrigation shutoff device that prevents an automatic sprinkler system from turning on during and after a rain storm. Rain shut-off sensors are wired to a sprinkler timer and override the scheduled irrigation when a sensor on the shutoff device detects water [30] . When the collected rainwater has evaporated from the sensor, scheduled irrigations resume.…”

“…(4) Mobile connectivity: Several smart controller products incorporate onboard home network connectivity through either wireless networking technology (WiFi) or a local area network (LAN) connection [30,34] . The unit can connect to the internet through these.…”

Reduced Impact Development Practices at “Restoration”

“…There are immediate technical fixes that can address at least part of the problem. Research conducted at the University of Florida is finding that soil moisture sensors that override timer-based controls when soil moisture content is adequate can reduce landscape irrigation water demand by more than 50% with no ill effects on the appearance or viability of turf [5,6,7]. In a comparison of irrigation use by Pinellas County homeowners with or without a rain shut-off device or soil moisture sensor on the irrigation system, homeowners with conventional timer-based controls applied about 10" of irrigation water.…”

Evaluation of Evapotranspiration-Based and Soil-Moisture-Based Irrigation Control in Turf

“…Variability and irregularity in rainfall make irrigation scheduling difficult in North Carolina and an efficient irrigation schedule (applying the right amount of water at the right time) is essential in meeting the dual goals of water conservation and acceptable turf quality. Under-irrigation and over-irrigation can negatively affect turfgrass quality (Cardenas-Lailhacar et al, 2005) and over-irrigation results in waste of water and leaching of nutrients. With increasing competition for water resources, controllers that use feedback technologies show promise for improved water management.…”