Implementation of Soil Moisture Sensor Based Automated Irrigation in Woody Ornamental Production1

Abstract

Abstract A soil moisture sensor-based automated irrigation system was trialed in a commercial ornamental nursery over the 2014-2015 growing seasons. In both years, use of the sensor-based system resulted in an approximate 50% reduction in irrigation application (volume) when compared to grower-managed irrigation. No differences in growth and equivalent or slightly reduced crop losses were noted when comparing the sensor-based irrigation system to grower-managed irrigation in production of Pieris japonica, Hydrangea quercifolia, and Kalmia latifolia. In 2014, Rhododendron catawbiense had equivalent canopy size and reduced mortality when comparing sensor-based irrigation to grower-managed irrigation. However, in 2015 irrigation control with the sensor-based system resulted in significant (>50%) Rhododendron losses. High mortality was thought to have resulted from use of averaged (across crop species) soil moisture readings to establish irrigation set points. Canopy structure of Rhododendron obstructed water capture to a greater degree than the other three species due to canopy architecture. This effect, combined with precision irrigation applications, resulted in persistent drought conditions within the Rhododendron block. Soil moisture sensor-based automated irrigation can be an effective means of automating irrigation. Support from crop consultants is highly desirable to minimize disruption and maximize adoption during implementation. Index words: Pieris Japonica D. Don ex G. Don ‘Prelude', Hydrangea quercifolia W. Bartram ‘Jet Stream', Rhododendron catawbiense Michx. ‘Roseum Elegans', Kalmia latifolia L. ‘Sarah', irrigation groupings, automation, canopy structure, irrigation capture, technology transfer, outreach, education, precision irrigation Species used in this study: Japanese andromeda ‘Prelude' (Pieris Japonica D. Don ex G. Don); Oakleaf hydrangea ‘Jet Stream' (Hydrangea quercifolia W. Bartram); Rhododendron ‘Roseum Elegans' (Rhododendron catawbiense Michx.); Mountain laurel ‘Sarah' (Kalmia latifolia L.)