Needle-type in situ water content sensor with polyethersulfone polymer membrane

A needle-type water content sensor with a polyethersulfone (PES, poly(4-phenoxy-co-4-benzensulfone)) polymer membrane is proposed for the low-invasive, direct in situ measurement of plant water content (PWC). When the PWC sensor is inserted into a plant, the electrical impedance of PES is determined by the amount of absorbed water, which indicates the PWC. In situ measurement of PWC was successfully demonstrated for a strawberry plant (Fragaria × ananassa) and the application feasibility of the sensor to in situ PWC measurement for irrigation agriculture was verified.