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 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.
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
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. Eagle.io 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 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.
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.