A goal of irrigation best management practices in container nurseries is to conserve water while maintaining optimal plant growth and quality. A web-based, container irrigation management program (CIRRIG) was developed to automatically provide daily irrigation run times for sprinkler-irrigated crops in container nurseries. The program estimates evapotranspiration rates based on weather uploaded from a weather station located on-site and plant production conditions monitored in each zone and adjusts irrigation run times based on irrigation application rate, the plant’s irrigation-capturing ability (for sprinkler irrigation), desired leaching fraction, and irrigation system uniformity. For this project we interfaced CIRRIG output with a programmable logic controller (PLC) to automatically irrigate a sprinkler-irrigated crop at a container nursery in Florida. Sweet viburnum (Viburnum odoratissimum) in 10-inch-diameter containers were grown by the nursery for 24 weeks in adjacent irrigation zones, one controlled automatically using CIRRIG and the other by the nursery’s traditional practice of manually turning on and off irrigation. Water use was monitored with flowmeters and plant growth by measuring plant size and shoot dry weight periodically throughout the trial. Plant growth was not different (P < 0.05) because of irrigation practice. CIRRIG reduced water use during the study period by 21% (42 vs. 53 inches) compared with the nursery’s irrigation practice. An assessment of the water-saving benefits of making daily adjustments to irrigation run times based on weather including rain indicated savings of 25% and 40% compared with biweekly adjustments with and without automatic rain cutoff, respectively. This trial demonstrated that CIRRIG coupled with an on-site weather station and a computer-controlled irrigation system can be used to manage irrigation while conserving water in a container nursery.
Irrigation scheduling in container nurseries is challenging due to the wide range of plant production conditions that must be accounted for at any given time. An irrigation scheduling system should also consider weather affecting evapotranspiration to apply proper amounts of water that will ensure optimal growth with minimal runoff (container drainage). We developed an automated system that relies on routine leaching fraction (leachate/water applied) testing and real-time weather recorded on-site to make adjustments to irrigation. A web-based program (CIRRIG) manages irrigation zone inputs [weather and leaching fraction (LF) test results] and outputs irrigation run times that can be implemented automatically with programmable logic controllers. In this study conducted at a nursery in central Florida, we compared the automated technology (CIRRIG) with the nursery’s traditional irrigation practice (TIP) of manually adjusting irrigation based on substrate moisture status of core samples taken twice weekly. Compared with TIP, CIRRIG reduced water use in six of seven unreplicated trials with water savings being greater for microirrigated crops grown in large containers than for sprinkler-irrigated crops in small containers. Reduced pumping cost associated with water savings by CIRRIG was estimated to be $3250 per year, which was insignificant compared with the labor savings of $35,000 to $40,000 anticipated by the nursery using CIRRIG in lieu of TIP. At the end of the project, the necessary hardware was installed to expand CIRRIG nursery-wide and control 156 zones of irrigation.