Increasing Water Use Efficiency by Addressing Sensor Cost Barriers Using Novel Technology

The project objective is to greatly reduce the cost of monitoring soil water content in highly-resolved vertical profile to promote increased adoption of more efficient water management tools. Cost is the most significant barrier to adoption of sophisticated data-driven irrigation management in permanent agriculture. Highly-resolved vertical soil water profiles are needed to learn soil-specific hydraulic response and to accurately infer crop water uptake and deep drainage fluxes from monitored changes in the storage profile. Basing irrigation decisions on the time-varying soil hydraulic behavior learned in situ will enable the improvement of water and energy conservation, resource protection, and adaptability to climate change. The massive proliferation of wireless accessories has driven the cost of integrated circuit (IC) based programmable RF transceivers unprecedentedly low and usability unprecedentedly high. We propose to repurpose low-cost RF chips as soil water sensing devices arranged in a dense linear profile for highresolution vertical water content profiling. Electromagnetic waves transmitted through a material are affected by the dielectric permittivity of the material. Preliminary work has demonstrated a relationship between signal strength and permittivity of the surrounding material which is a strong indicator of soil water content. The new multi-level sensor will replace and improve on significantly more expensive multilevel soil moisture technologies currently on the market. Applying a machine intelligence (MI) we have developed, this and other multi-level sensors can accurately determine root uptake and deep drainage which form the basis for a sophisticated irrigation decision support system offered by our precision ag commercialization partner.