A leaf-mounted capacitance sensor for continuous monitoring of foliar transpiration and solar irradiance as an indicator of plant water status

Abstract

A leaf-mounted sensor is described which detects condensing water vapour originating from leaf transpiration, taking advantage of a passive temperature gradient across the sunlit leaf and the underneath sensor plate, and simultaneously monitors incident solar radiation. The simple and low-cost device enables the qualitative assessment of plant water status by comparing the diurnal patterns of leaf transpiration and solar irradiance. A close correlation between condensation and irradiance occurs in conditions of unrestricted water supply, whereas a deviation of their course likely indicates a suboptimal plant water status.

Continuous Plant-Based and Remote Sensing for Determination of Fruit Tree Water Status

“…It combines two heat-pulse methods: The HR, effective for low and reverse flows, and CHP, suitable for moderate to high flows, within a single set of sensor probes [166] Ratio heat pulse T m Ratio It uses the ratio of temperature maxima on downstream and side probes [88] (3) Field It measures the shape variations of a continuous heat field within the sapwood by utilizing tangential and axial probes…”

“…In 2023, Talheimer developed the leaf-mounted capacitance sensor (LMCS) (Figure 2) [88]. This is a very low-cost sensor that is able to continuously measure a signal that follows the patterns of leaf transpiration and solar irradiance.…”

“…(2) pulse [88,[160][161][162][163][164][165][166], (3) field [167], and (4) balance [38,168]. Such methods are briefly described in the following table (Table 1):…”