The soil moisture sensor based on soil dielectric property

Huan, Zhan; Wang, Hui; Li, Chen; Wan, Caiyan

doi:10.1007/s00779-016-0975-z

Cited by 13 publications

(9 citation statements)

References 7 publications

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“…However, with increasing soil temperatures, these surface forces reduce in strength, thereby causing a positive relationship between water content and temperature [39]; the variation of soil volumetric water content from 7.5% to 28% in Figure 7 also supports this conclusion. Meanwhile, the dielectric constant of water decreases with increasing temperature [29,30], and as the proportion of water contained in the soil increases, the effect of surface forces on soil particles gradually decreases, and the effect of the dielectric constant of water on the overall dielectric constant of the soil gradually increases [40]; as the temperature increases, the rate of increase in the volumetric water content of the soil shows a decrease, as evidenced by the rate of change of the curve in Figure 7; when the water in the soil is close to saturation, the effect of the dielectric constant of water on the overall dielectric constant of the soil gradually increases due to the dielectric constant which dominates the overall dielectric constant of the soil; the volumetric water content of the soil decreases slightly with increasing temperature, so the output of the sensor seems to decrease slightly with increasing temperature at 28.50% to 31.50%. Change in temperature affects not only the dielectric constant of the soil under test but also the dielectric constant [27,28].…”

Section: Resultsmentioning

confidence: 99%

A Novel Portable Soil Water Sensor Based on Temperature Compensation

Tian

Xie

et al. 2022

Journal of Sensors

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Soil water sensors based on the standing wave rate (SWR) principle are affected by temperature in long-term operation. To address this problem, a temperature compensation model based on the binary regression analysis method is proposed. The measurement results of the temperature-compensated standing wave rate (TCSWR) sensor at different temperatures and soil volumetric water content are analyzed, and the least-squares principle is used to identify the parameters to be determined in the compensation model for temperature for the SWR soil water sensor. A portable tapered TCSWR sensor with built-in temperature compensation model was developed on this basis. The calibration results show that the standing wave measurement circuit of the TCSWR sensor can effectively respond to changes in soil water, and the coefficient of the fitted equation exceeds 0.95. A comparison of the results before and after temperature compensation proves that compensation can significantly reduce the measurement error of the TCSWR sensor and improve the measurement accuracy. The static and dynamic characteristics of the TCSWR sensor show that the measurement range of the TCSWR sensor is7.50%-31.50%, the measurement accuracy is ±0.63%, the stability is good, the resolution is a minimum of 0.05%, and the dynamic response time is less than 1 s. The absolute error of the TCSWR sensor measurement is less than 1% in comparison with similar sensors, demonstrating that the measurement results of the TCSWR sensor are reliable.

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Section: Resultsmentioning

confidence: 99%

A Novel Portable Soil Water Sensor Based on Temperature Compensation

Tian

Xie

et al. 2022

Journal of Sensors

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“…To obtain a soil water content value from dielectric soil measurements, it is necessary to perform calibration specific to a given soil (or soilless growing medium). Results of numerous studies have proved that (after proper calibration) this type of sensors can be useful as a reliable moisture monitoring tool in sustainable use of water resources in agriculture (irrigation scheduling) and is suitable for building large-scale agricultural wireless sensor networks [HUAN et al 2017;KENNEDY et al 2003;KLAMKOWSKI, TREDER 2017].…”

Section: Resultsmentioning

confidence: 99%

Journal of Water and Land Development

2022

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The suitability of a new wireless smart farming system for controlling irrigation and fertilization of horticultural plants was assessed in the study. The system (name: AGREUS ® ) includes sensors (soil moisture, salinity, weather data), executive modules (valve modules), and an application available on the web portal (accessed through computers and mobile devices). The studies were performed under laboratory and field conditions. Laboratory tests included appraisal of the precision of soil moisture and salinity measurements carried out with the soil probe (comparison with the results obtained by laboratory methods). Operational tests were conducted in field trials. In these trials, assessment of the possibility of practical control of irrigation and monitoring soil salinity was performed in an apple orchard. The conducted analyses have shown the usefulness of the system, not only for automatic control of irrigation but also for making decisions about the necessity to fertilize plants. The system enables continuous monitoring of changes in soil moisture and salinity, including the migration of minerals across the soil profile (using a probe with several measuring elements) as a result of the applied irrigation or rainfall. The system allows for automatic application of irrigation or fertigation depending on the adopted soil moisture and salinity thresholds. However, the tests showed that a salinity index calculated by the system does not directly correspond to the salinity values determined by laboratory methods. For this reason individual interpretation and determination of optimal ranges for plants is required.

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“…Currently, humidity monitoring technologies commonly fall into two categories: contact and non-contact. Non-contact technologies, such as those utilizing microwave [17][18][19][20], infrared [21,22], or ultrasonic waves, enable moisture measurement without direct contact with the medium. While these methods avoid damaging the medium, their sensing accuracy typically lags behind that of contact methods, and they often involve higher costs.…”

Section: Introductionmentioning

confidence: 99%

A Design Method for an SVM-Based Humidity Sensor for Grain Storage

Liu,

Song,

Zhu

et al. 2024

Sensors

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One of the crucial factors in grain storage is appropriate moisture content, which plays a significant role in reducing storage losses and ensuring quality. However, currently available humidity sensors on the market fail to meet the demands of modern large-scale grain storage in China in terms of price, size, and ease of implementation. Therefore, this study aims to develop an economical, efficient, and easily deployable grain humidity sensor suitable for large-scale grain storage environments. Simultaneously, it constructs humidity calibration models applicable to three major grain crops: millet, rice, and wheat. Starting with the probe structure, this study analyzes the ideal probe structure for grain humidity sensors. Experimental validations are conducted using millet, rice, and wheat as experimental subjects to verify the accuracy of the sensor and humidity calibration models. The experimental results indicate that the optimal length of the probe under ideal conditions is 0.67 m. Humidity calibration models for millet, rice, and wheat are constructed using SVM models, with all three models achieving a correlation coefficient R2 greater than 0.9. The measured data and model-calculated data show a linear relationship, closely approximating y = x, with R2 values of all three fitted models above 0.9. In conclusion, this study provides reliable sensor technological support for humidity monitoring in large-scale grain storage and processing, with extensive applications in grain storage and grain safety management.

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The soil moisture sensor based on soil dielectric property

Cited by 13 publications

References 7 publications

A Novel Portable Soil Water Sensor Based on Temperature Compensation

A Novel Portable Soil Water Sensor Based on Temperature Compensation

Journal of Water and Land Development

A Design Method for an SVM-Based Humidity Sensor for Grain Storage

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