Use of a Bulk Soil Capacitance Sensor in Small Containers To Control Irrigation in a Greenhouse

Automating greenhouse irrigation based on growing medium water content measured by sensors, instead of a tactile, timing, or weighing method, has been done with large containers. Using sensors with small containers (e.g., 10 in3 [164 cm3]) commonly used in forest and native plant nurseries, however, has not been done. We tested the EC-5 sensor (METER Group, Pullman, WA) by examining calibration relationships for small containers as they dried from container capacity. These relationships were highly significant down to 63 percent saturation. Three sensors were then used to control irrigation for 90 days. One sensor drifted approximately 10 percent, and the other two were stable. Repositioning two sensors resulted in no change for one and an increase of 10 percent for the other. These sensors have potential for automating irrigation in small containers provided they are calibrated, tracked for sensor drift, and recalibrated after repositioning. This paper was presented at the Joint Annual Meeting of the Northeast Forest and Conservation Association, the Southern Forest Nursery Association, and the Intertribal Nursery Council (Walker, MN, July 31 to August 3, 2017).

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Author(s): Steven O. Link, Patrick F. Mills, Rodney S. Skeen

Publication: Tree Planters' Notes - Volume 61, Number 2 (2018)

Event: Joint Annual Meeting of the Northeast Forest and Conservation Association, the Southern Forest Nursery Association, and the Intertribal Nursery Council
2017 - Walker, MN

Volume: 61

Number: 2