The Effect of Soil Iron on the Estimation of Soil Water Content Using Dielectric Sensors

Kargas, George; Londra, Paraskevi A.; Anastasatou, Marianthi; Moustakas, N.

doi:10.3390/w12020598

Cited by 9 publications

(7 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Gravimetric measurements of soil water content can also give some indications of water availability for plants and can in some conditions be the only method practically feasible. Sensors measuring soil moisture frequently overestimate soil humidity in soils with high levels of iron [ 113 ] and in this case, water content can be measured gravimetrically.…”

Section: Environmental Variablesmentioning

confidence: 99%

Quinoa Phenotyping Methodologies: An International Consensus

Stanschewski¹,

Rey²,

Fiene³

et al. 2021

Plants

View full text Add to dashboard Cite

Quinoa is a crop originating in the Andes but grown more widely and with the genetic potential for significant further expansion. Due to the phenotypic plasticity of quinoa, varieties need to be assessed across years and multiple locations. To improve comparability among field trials across the globe and to facilitate collaborations, components of the trials need to be kept consistent, including the type and methods of data collected. Here, an internationally open-access framework for phenotyping a wide range of quinoa features is proposed to facilitate the systematic agronomic, physiological and genetic characterization of quinoa for crop adaptation and improvement. Mature plant phenotyping is a central aspect of this paper, including detailed descriptions and the provision of phenotyping cards to facilitate consistency in data collection. High-throughput methods for multi-temporal phenotyping based on remote sensing technologies are described. Tools for higher-throughput post-harvest phenotyping of seeds are presented. A guideline for approaching quinoa field trials including the collection of environmental data and designing layouts with statistical robustness is suggested. To move towards developing resources for quinoa in line with major cereal crops, a database was created. The Quinoa Germinate Platform will serve as a central repository of data for quinoa researchers globally.

show abstract

Section: Environmental Variablesmentioning

confidence: 99%

Quinoa Phenotyping Methodologies: An International Consensus

Stanschewski¹,

Rey²,

Fiene³

et al. 2021

Plants

View full text Add to dashboard Cite

show abstract

“…The probe calibration is always necessary, but it is particularly important for capacitance probes working at low frequency, especially when used in a medium having high iron content. The iron content affects the imaginary component (ε") of the dielectric constant of the soil/water system [55]. For these soils, the difference between actual and estimated values by the manufacturer parameters tends to increase as the degree of saturation of soil increases.…”

Section: Discussionmentioning

confidence: 99%

“…As reported by Robinson et al [57], the iron oxide content, coupled with the length of sensor rods used, play an important role in capacitance probe working at 100 MHz, such as the PR2/6 probe. However, recent research has shown that the effects of iron content are more evident for instruments working at even lower frequencies (cf., a WET sensor working at 50 MHz, [55]). The effects of an accurate calibration are also evident when analyzing the temporal variations of soil water content with depth in the experimental field.…”

Section: Discussionmentioning

confidence: 99%

Processes in the Unsaturated Zone by Reliable Soil Water Content Estimation: Indications for Soil Water Management from a Sandy Soil Experimental Field in Central Italy

2020

View full text Add to dashboard Cite

Reliable soil moisture data are essential for achieving sustainable water management. In this framework, the performance of devices to estimate the volumetric moisture content by means dielectric properties of soil/water system is of increasing interest. The present work evaluates the performance of the PR2/6 soil moisture profile probe with implications on the understanding of processes involving the unsaturated zone. The calibration at the laboratory scale and the validation in an experimental field in Central Italy highlight that although the shape of the moisture profile is the same, there are essential differences between soil moisture values obtained by the calibrated equation and those obtained by the manufacturer one. These differences are up to 10 percentage points for fine-grained soils containing iron oxides. Inaccurate estimates of soil moisture content do not help with understanding the soil water dynamic, especially after rainy periods. The sum of antecedent soil moisture conditions (the Antecedent Soil moisture Index (ASI)) and rainfall related to different stormflow can be used to define the threshold value above which the runoff significantly increases. Without an accurate calibration process, the ASI index is overestimated, thereby affecting the threshold evaluation. Further studies on other types of materials and in different climatic conditions are needed to implement an effective monitoring network useful to manage the soil water and to support the validation of remote sensing data and hydrological soil models.

show abstract

“…However, due to their relatively low operating frequency, capacitance sensors are susceptible to secondary effects (e.g., induced by strong variations in soil temperature and salinity-induced electrical conductivity) that affect their measurement accuracy and precision [8][9][10][11][12][13][14][15][16]. Therefore, proper calibration is mandatory to reliably convert the soil dielectric permittivity into soil water content, especially for fine-textured soils [17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Temperature-Corrected Calibration of GS3 and TEROS-12 Soil Water Content Sensors

Nasta,

Coccia,

Lazzaro

et al. 2024

Sensors

View full text Add to dashboard Cite

The continuous monitoring of soil water content is commonly carried out using low-frequency capacitance sensors that require a site-specific calibration to relate sensor readings to apparent dielectric bulk permittivity (Kb) and soil water content (θ). In fine-textured soils, the conversion of Kb to θ is still challenging due to temperature effects on the bound water fraction associated with clay mineral surfaces, which is disregarded in factory calibrations. Here, a multi-point calibration approach accounts for temperature effects on two soils with medium to high clay content. A calibration strategy was developed using repacked soil samples in which the Kb-θ relationship was determined for temperature (T) steps from 10 to 40 °C. This approach was tested using the GS3 and TEROS-12 sensors (METER Group, Inc. Pullman, WA, USA; formerly Decagon Devices). Kb is influenced by T in both soils with contrasting T-Kb relationships. The measured data were fitted using a linear function θ = aKb + b with temperature-dependent coefficients a and b. The slope, a(T), and intercept, b(T), of the loam soil were different from the ones of the clay soil. The consideration of a temperature correction resulted in low RMSE values, ranging from 0.007 to 0.033 cm3 cm−3, which were lower than the RMSE values obtained from factory calibration (0.046 to 0.11 cm3 cm−3). However, each experiment was replicated only twice using two different sensors. Sensor-to-sensor variability effects were thus ignored in this study and will be systematically investigated in a future study. Finally, the applicability of the proposed calibration method was tested at two experimental sites. The spatial-average θ from a network of GS3 sensors based on the new calibration fairly agreed with the independent area-wide θ from the Cosmic Ray Neutron Sensor (CRNS). This study provided a temperature-corrected calibration to increase the accuracy of commercial sensors, especially under dry conditions, at two experimental sites.

show abstract

The Effect of Soil Iron on the Estimation of Soil Water Content Using Dielectric Sensors

Cited by 9 publications

References 23 publications

Quinoa Phenotyping Methodologies: An International Consensus

Quinoa Phenotyping Methodologies: An International Consensus

Processes in the Unsaturated Zone by Reliable Soil Water Content Estimation: Indications for Soil Water Management from a Sandy Soil Experimental Field in Central Italy

Temperature-Corrected Calibration of GS3 and TEROS-12 Soil Water Content Sensors

Contact Info

Product

Resources

About