Dynamic modelling of lettuce transpiration for water status monitoring

Adeyemi, O., Grove, I.G., Peets, S., Domun, Y. and Norton, T. (2018) Dynamic modelling of lettuce transpiration for water status monitoring. Computers and Electronics in Agriculture, 155. pp. 50-57.

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Abstract

Real-time information on the plant water status is an important prerequisite for the precision irrigation management of crops. The plant transpiration has been shown to provide a good indication of its water status. In this paper, a novel plant water status monitoring framework based on the transpiration dynamics of greenhouse grown lettuce plants is presented. Experimental results indicated that lettuce plants experiencing adequate water supply transpired at a higher rate compared to plants experiencing a shortage in water supply. A data-driven model for predicting the transpiration dynamics of the plants was developed using a system identification approach. Results indicated that a second order discrete-time transfer function model with incoming radiation, vapour pressure deficit, and leaf area index as inputs sufficiently explained the dynamics with an average coefficient of determination of . The parameters of the model were updated online and then applied in predicting the transpiration dynamics of the plants in real-time. The model predicted dynamics closely matched the measured values when the plants were in a predefined water status state. The reverse was the case when there was a significant change in the water status state. The information contained in the model residuals (measured transpiration – model predicted transpiration) was then exploited as a means of inferring the plant water status. This framework provides a simple and intuitive means of monitoring the plant water status in real-time while achieving a sensitivity similar to that of stomatal conductance measurements. It can be applied in regulating the water deficit of greenhouse grown crops, with specific advantages over other available techniques.

Item Type: Article
Keywords: Plant water status, Transpiration, Modelling, System identification, Irrigation
Divisions: Crop and Environment Sciences
Depositing User: Ms Kath Osborn
Date Deposited: 22 Nov 2018 19:57
Last Modified: 10 Oct 2019 04:10
URI: http://hau.repository.guildhe.ac.uk/id/eprint/17363

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