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

Year 2014, Volume: 10 Issue: 4, 267 - 272, 01.08.2014

Rajveer Dhıllon Francisco Rojo Jed Roach Shrini Upadhyaya Mike Delwıche

Abstract

Studies have shown that measurement of plant water status (PWS) provides the key

information necessary to implement efficient irrigation management scheme in orchard and

vineyard crops. A pressure chamber is often used to measure PWS. However, this technique is

labor intensive, tedious and time-consuming. To address these issues, we developed a sensor suite

consisting of a thermal infrared (IR) sensor and relevant environmental parameters (ambient

temperature, photosynthetically active radiation (PAR), wind speed and relative humidity) and

tested it extensively in almond, walnut, and grape crops. The system was found to work well in all

three crops. However, this sensor suite was quite bulky and we noticed temporal drifts in the

calibration curve as the season progressed. To address these issues, we developed a continuous

leaf monitoring system that included same sensors as the sensor suite. We have deployed 22 such

leaf monitors in almond and walnut orchards in Nickels Soil Laboratory, Arbuckle, CA, USA and

interfaced them to a wireless mesh network so that data could be uploaded to the internet through

a gateway computer and accessed through the web. The system also included a controller capable

of actuating latching solenoid valves to manage precision irrigation in the orchard. Field data

collected from these experiments were used to calculate daily crop water stress index (CWSI). The

results showed that this system has the potential to be used as irrigation management tool as it

was able to provide daily CWSI values which followed similar pattern as the actual PWS values.

Keywords

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

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