Real Time Measurement of Water and Electrical Conductivity In Soilless Substrates, to Precisely Monitor and Control Irrigation and Fertigation Events

The precise monitoring and control of irrigation and electrical conductivity (EC) in real-time has been a goal for many nursery and greenhouse producers for many years, but most technologies are either extremely expensive or imprecise for widespread use in porous soilless substrates.  We have deployed a low-cost wireless sensor network, developed by Carnegie Mellon University, in a commercial cut-flower operation in Maryland. We are integrating Decagon Devices capacitance (Ech₂0-TM) and EC (5-TE) sensors into this network, to precisely monitor water content and EC in real time, so we can automatically control applications of water and nutrients based upon plant requirements. The challenge is to precisely measure spatial and temporal dynamics of water in real-time, so we can control precision irrigation scheduling, to improve the uniformity and quality of cut-flower Antirrhinum produced by this operation.  We are working towards a full integration of these control capabilities with the grower, so that he can fertigate based upon substrate matric potential or electrical conductivity set-points, so he can maximize net returns, conserve resources and limit environmental impacts from his operation.