Rajveer DHILLON, Francisco ROJO, Jed ROACH, Shrini UPADHYAYA, Mike DELWICHE

A Continuous Leaf Monitoring System for Precision Irrigation Management in Orchard Crops

Studies have shown that measurement of plant water status (PWS) provides the keyinformation necessary to implement efficient irrigation management scheme in orchard andvineyard crops. A pressure chamber is often used to measure PWS. However, this technique islabor intensive, tedious and time-consuming. To address these issues, we developed a sensor suiteconsisting of a thermal infrared (IR) sensor and relevant environmental parameters (ambienttemperature, photosynthetically active radiation (PAR), wind speed and relative humidity) andtested it extensively in almond, walnut, and grape crops. The system was found to work well in allthree crops. However, this sensor suite was quite bulky and we noticed temporal drifts in thecalibration curve as the season progressed. To address these issues, we developed a continuousleaf monitoring system that included same sensors as the sensor suite. We have deployed 22 suchleaf monitors in almond and walnut orchards in Nickels Soil Laboratory, Arbuckle, CA, USA andinterfaced them to a wireless mesh network so that data could be uploaded to the internet througha gateway computer and accessed through the web. The system also included a controller capableof actuating latching solenoid valves to manage precision irrigation in the orchard. Field datacollected from these experiments were used to calculate daily crop water stress index (CWSI). Theresults showed that this system has the potential to be used as irrigation management tool as itwas able to provide daily CWSI values which followed similar pattern as the actual PWS values.

Anahtar Kelimeler:

Leaf temperature, crop water stress index, cwsi, irrigation scheduling, continuous measurement, wireless mesh network, plant water status, almonds, walnuts

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