2018 ASHS Annual Conference

A web-based irrigation control system (CIRRIG, Container IRRIGation) developed at the University of Florida was evaluated in two production nurseries. CIRRIG inputs were onsite weather data, recent leaching fraction (LF) percentage, and sprinkler irrigation duration when LF was determined. CIRRIG used these inputs to calculate daily sprinkler duration needed to satisfy water demand for plants grown with pine bark and Florida peat substrates in 8-11 L containers. A programmable logic controller was used to control solenoid valves based on irrigation duration outputs from CIRRIG. An adjacent irrigation zone with the same plants was irrigated based on standard nursery practices. Six irrigation zone pairs of Ilex cornuta ʽBurfordii Nanaʼ, Juniperus davurica ʽParsonii’, Loropetalum chinensis ʽPlum’, Rhaphiolepis indica, and Viburnum odoratissimum were evaluated during 2016 and 2017. There were two zone pair evaluations for Ilex. The production time for each zone pair ranged from three to nine months depending on plant growth rate, plant size when evaluation started, and plant size when marketed. Plant heights and widths were measured when plants were of marketable size and total irrigation water applied was metered. The growth indices (height plus average width) were similar for all pairs except for Rhaphiolepis, which had a growth index of 28.8±0.6 for the CIRRIG zone compared to 23.3±0.4 for plants irrigated based on standard practices used at the nursery. CIRRIG resulted in 1% to 13% decrease in water applied for Ilex, Loropetalum, Rhaphiolepis, and Viburnum, and 8% and 35% increased in water applied for Juniperus and Ilex (second evaluation), respectively. These results indicate that similar plant growth was achieved with CIRRIG that automatically adjusted daily amounts of irrigation water applied compared to plants irrigated with traditional practices used at the nurseries. Irrigation water applied in four of the six zone pairs was less or similar when CIRRIG was used compared to the nurseries’ irrigation practices. However, it is important to consider other benefits of CIRRIG such as; electronic history of daily irrigation applications, the ability to control and monitor irrigation offsite via the internet, and time saved with automatic adjustment of irrigation duration.