Comparison of a new plant-based irrigation control method with light-based irrigation control for greenhouse tomato production

摘要

A new control algorithm utilizing an off-the-shelf electronic balance to directly measure plant water use was developed to control irrigation of a greenhouse tomato crop. Water use was measured by summing the change in weight of the medium over shorttime-periods, rather than by examining its absolute weight over time. Experiments were then conducted to compare the new algorithm to the current industry-standard light-based approach in terms of irrigation consistency and frequency. Results showed thatboth control algorithms were effective; the plants did not experience long periods without watering. The weight-based approach produced a more consistent amount of leachate, indicating that it was more capable of supplying water as the crop needed it. Furthermore, it had an ability to trigger irrigation at night. A control strategy encompassing both weight-based and light-based inputs is recommended to improve irrigation efficiency.