Crop Monitoring

Calculated VPD & Soil Moisture
Calculated VPD & Soil Moisture

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Calculated VPD & Soil Moisture
Calculated VPD & Soil Moisture

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In late 2018, ICT International installed a monitoring program in an avocado orchard with the specific objective to reduce rates of fruit drop (abscission), hence yield loss, by improved irrigation scheduling.

The Site


The farm, located on the Mid-North Coast of NSW Australia, had previously suffered crop
losses caused by water stress during flowering and fruit set. Seeking a solution to better detect this risk required real time monitoring to enable pro-active management of irrigation and canopy humidity.

Project Background


Avocado trees are particularly sensitive to heat (and thus water stress) at the time of flowering and fruit set. Water stress can result in flower and fruit drop, thereby reducing yield. By forecasting the risk factors which contribute to plant water stress, notably low soil moisture and high Vapour Pressure Deficit (VPD), management decisions
can be implemented to minimise the risk of fruit drop.

The Solution: Crop Monitoring Sensors

  • Weather station

  • Soil Moisture Sensors

  • Temperature Sensors

  • High Resolution Dendrometers measuring avocado tree trunk diameter

  • Micro-climate sensors outside and within the canopy measuring temperature, relative humidity and calculated VPD.

Integrated Into a LoRaWAN Network


Data from the sensors is transmitted over a private LoRaWAN network to a Gateway utilising a fixed-point network connection. is used for data storage / visualisation and alarming of soil moisture, VPD and Maximum Daily trunk Contraction (MDC).

The system notifies operators (via SMS and email) when irrigation is necessary to avoid plant water stress and potential fruit drop, hence crop loss.


The Outcome


The sensor network was installed in December 2018, prior to a month of extreme heat which occurred during flowering and fruit set. Over January, during fruit set, the sensor network detected two significant plant water stress events, with local VPD levels rising above 5kPa.

Low soil moisture during the second event resulted in severe plant water stress, reflected by higher levels of MDC of the trunk. Managers observed high numbers of fruit drop coinciding with the second event.


Dashboard View of Past & Realtime Data


Remotely controllable irrigation systems are currently being installed. The monitoring system will provide property owners the information required to remotely control irrigation to reduce plant water stress events.