Impact of calibrating a low-cost capacitance-based soil moisture sensor on AquaCrop model performance

  • 0Chair of Hydrology and River Basin Management, Technical University of Munich, Arcisstrasse 21, 80333, Munich, Germany.

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Summary

This summary is machine-generated.

Calibrating low-cost soil moisture sensors is essential for accurate agro-hydrological modeling. Field calibration improved crop water productivity by enhancing soil moisture simulations in the AquaCrop model.

Area Of Science

  • Agricultural Science
  • Hydrology
  • Sensor Technology

Background

  • Effective irrigation management relies on integrating sensor data with agro-hydrological models.
  • Data-scarce regions require parsimonious crop water models and low-cost, maintainable soil moisture sensors for practical application.
  • Site-specific calibration of soil moisture sensors is crucial for reliable irrigation management.

Purpose Of The Study

  • To calibrate low-cost capacitance-based soil moisture sensors using various methods.
  • To assess the impact of sensor calibration on the FAO AquaCrop Open Source (AquaCrop-OS) model's performance.
  • To recommend best practices for sensor calibration in crop modeling.

Main Methods

  • Calibration of Spectrum Inc. SM100 soil moisture sensors using multiple least squares and machine learning models with laboratory and field data.
  • Field-based piece-wise linear regression was identified as the optimal calibration technique.
  • The calibrated sensor data was used to adjust soil hydraulic parameters in the AquaCrop-OS model.

Main Results

  • Field-based piece-wise linear regression yielded the best calibration results (r²=0.76).
  • Calibrated low-cost sensor data significantly improved AquaCrop-OS soil moisture simulations and water productivity.
  • Machine learning models showed poor field validation due to overfitting; using literature values for calibration was a viable alternative if field calibration was not feasible.

Conclusions

  • Calibrating low-cost soil moisture sensors is essential for improving crop water productivity through enhanced agro-hydrological modeling.
  • Field calibration against a reference sensor is recommended for optimal results.
  • In the absence of calibration, using literature values for soil hydraulic parameters can be a cost-effective alternative without compromising model performance.