Абзалов et al. (2026) Анализ Принципа Измерения Влажности Eмкостным Способом

Identification

• Journal: The Bulletin of Izhevsk State Agricultural Academy
• Year: 2026
• Date: 2026-03-31
• Authors: М.А. Абзалов, С.М. Бакиров, Т.А. Широбокова, С.С. Елисеев
• DOI: 10.48012/1817-545720261_149-157

Research Groups

• Vavilov University, Saratov, Russia
• Udmurt State Agricultural University, Izhevsk, Russia

Short Summary

This paper analyzes the capacitance method for soil moisture measurement, identifies factors affecting accuracy, and proposes an improved sensor system with primary and secondary transducers operating at specific frequencies to enhance sensitivity and address limitations of existing layered soil moisture sensors.

Objective

• To identify the main patterns and ways to achieve high accuracy in soil moisture measurement and establish its basic principles.

Study Configuration

• Spatial Scale: The study focuses on layered soil moisture control, specifically mentioning depths of 10, 20, 30, 40 cm for the proposed sensor and analyzing existing sensor data for 30-70 cm depth.
• Temporal Scale: Analysis of existing sensor data over a period of 20 days (e.g., June 2 to June 18, 2025) and specific measurements on June 7 and June 18, 2025.

Methodology and Data

• Models used:
  • Mathematical models describing sensor output as a function of physical quantity (s = f(m)).
  • Linear approximation for sensor sensitivity (Δs = SΔm).
  • Statistical methods for data processing (mean, standard deviation, Gaussian distribution).
  • Differential equations (first and second order) to describe dynamic sensor behavior and frequency characteristics.
  • Equations for resonant frequency in oscillatory circuits (series and parallel).
  • Method of least squares for calibration curve approximation.
• Data sources:
  • Readings from existing layered soil moisture sensors (Status Agro LLC).
  • Control measurements of soil moisture using the thermostatic-gravimetric method.
  • Precipitation data (Status Agro LLC).
  • Theoretical analysis of physical principles (dielectric permittivity, electromagnetic wave interaction).

Main Results

• Existing capacitance-based layered soil moisture sensors (e.g., from Status Agro LLC) exhibit significant systematic errors, particularly at depths of 30-70 cm, showing little to no change in moisture readings over extended periods (e.g., 20 days) even with precipitation or irrigation.
• Factors influencing measurement accuracy include temperature, density, composition of the measured substance (minerals, salts), atmospheric pressure, electric and magnetic fields, and power supply variations.
• An improved soil moisture measurement system is modeled, featuring a secondary transducer with two frequency generators (700 Hz and 7700 Hz) utilizing a Wien bridge, designed to create oscillatory circuits with primary transducers (capacitive sensors) at different depths (e.g., 10, 20, 30, 40 cm).
• This dual-frequency approach aims to leverage the high dipole moment of water molecules for enhanced response and sensitivity, addressing the limitations of current layered sensors.
• The proposed frequencies (700 Hz and 7700 Hz) require further laboratory validation and optimization.

Contributions

• Comprehensive analysis of the capacitance method for soil moisture measurement, highlighting its physical principles and limitations of existing implementations.
• Identification of key factors affecting the accuracy of capacitance-based soil moisture sensors, particularly systematic errors in layered control.
• Development of a conceptual model for an improved soil moisture measurement system, including a novel secondary transducer design with dual-frequency generators (700 Hz and 7700 Hz) to enhance sensitivity and address issues with current layered sensors.
• Justification for the selection of primary and secondary transducers aimed at achieving higher accuracy and responsiveness in soil moisture monitoring.

Funding

[No explicit funding information was provided in the paper.]

Citation

@article{Абзалов2026Анализ,
  author = {Абзалов, М.А. and Бакиров, С.М. and Широбокова, Т.А. and Елисеев, С.С.},
  title = {Анализ Принципа Измерения Влажности Eмкостным Способом},
  journal = {The Bulletin of Izhevsk State Agricultural Academy},
  year = {2026},
  doi = {10.48012/1817-5457_2026_1_149-157},
  url = {https://doi.org/10.48012/1817-5457_2026_1_149-157}
}