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System for measuring plant transpiration

automatic irrigationDrought monitoringESTECHSmart membraneTranspirationWater status monitoring

Introduction

The invention proposes a device to be used in open fields and greenhouses for precision irrigation management, ensuring a reduction of waste water volumes.
The device reproduces a complex biophysical process (i.e. transpiration) by integrating an intelligent membrane that is capable of reproducing the stomatal behavior of the crop according to the soil water status.

Technical features

The water flow transpired from a vegetated surface (Ta) represents an agro-environmental variable of great importance in order to manage the water resources of a territory. The device reproduces the transpiration process of a crop system by integrating an intelligent membrane (analogous of the stomatal complex) for controlling the micro-hydraulic flow of water vapor exchange with the atmosphere. The electrical stimulus that activates the intelligent membrane is a function of a stress coefficient, which is quantified through the continuous and multi-level measurement (root profile) of soil moisture. Once the gradient between the interior of the device’s chamber (analogous of the sub-stomatal chamber) and the atmosphere is known, and the lowest boundary conditions (in terms of soil water content) are measured, the control system will instruct the intelligent membrane to update the settings to the current hydraulic resistance measurements.
The device contains all the structural (minimal encumbrance and robustness) and electronic characteristics (low consumption and easy management of the output signal) in order to be implemented in wireless sensors nets (WSN).

Possible Applications

  • Precision quantification of irrigation volumes and irrigation timing of enclosed growing systems (greenhouses), of open fields and urban environments;
  • Monitoring the drought phenomena of a territory;
  • Definition of bioclimatic indices of the urban environment, linked to the human well-being.

Advantages

  • Reproduces a complex biophysical process through intelligent membranes;
  • Mathematical simplification and exclusion of crop coefficients;
  • No needs of wind speed measurement as an input: very variable in scattered systems and with uneven surfaces (e.g. urban environment);
  • Smart design and simplified electronics;
  • Increase in accuracy as compared to estimation methods based on weather forcing and hydraulic functions of soil, plant and atmosphere (agrohydrological models).