Quantification of Rockwool Substrate Water Content using a Capacitive Water Sensor

Baek, Jeong-Hyeon; Park, Jusung; Lee, Ho-Jin; An, Jin-Hee; Choi, Eun-Young

doi:10.12791/ksbec.2021.30.1.027

Cited by 1 publication

(1 citation statement)

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“…Choi et al studied moisture changes in the coir fiber of tomatoes using a frequency-domain reflectometer sensor [18]. Baek et al conducted a quantitative study on the moisture content of the rockwool matrix using a capacitive moisture sensor and established an empirical equation for the relationship between capacitance value and moisture content [19]. Rhie studied changes in the physical properties of coir and perlite substrates at different ratios and calibrated a volumetric water content capacitive moisture sensor [20].…”

Section: Introductionmentioning

confidence: 99%

Investigation of Dielectric Measurement Model for Coconut Fiber Water Content and the Associated Factors

Yan,

Chen,

Yang

et al. 2023

Sustainability

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Coconut fiber has excellent permeability and water retention properties, making it a popular choice as an organic substrate for cultivation in the field of facility agriculture. To investigate the dielectric properties of coconut fiber and develop an accurate measurement model for dielectric water content, a vector network analyzer was used to measure the relative dielectric permittivity of coconut fiber and study the dielectric properties of coconut fiber under different volumetric water contents, temperatures, and salinities. The results indicated that the relative dielectric permittivity of the coconut fiber increased with increasing volumetric water content. The optimal frequency range for measuring the water content of the coconut fiber was 200 MHz–3 GHz, with an optimal frequency of 210 MHz. The dielectric measurement model for the water content in the coconut fiber established at this frequency demonstrated good applicability, with an R2 of 0.9704 and RMSE of 0.0453 cm3/cm3. At the same moisture level (θV of approximately 30% and 50%), the error in the real part of the dielectric permittivity was less than 1.35 between 15 and 35 °C, and the error in the moisture content was less than 0.0339 cm3/cm3. The error due to the salinity was 0.0750 cm3/cm3. The experimental results showed that the modeling of the water content measurement of coconut fiber at 210 MHz can be applied to general greenhouse environmental conditions. This study serves as a valuable reference for calibrating the moisture monitoring sensors used in greenhouses for coir cultivation substrates, emphasizing the need for non-destructive, real-time monitoring of moisture content.

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Section: Introductionmentioning

confidence: 99%