scholarly journals An Investigation of the Accuracy of EC5 and 5TE Capacitance Sensors for Soil Moisture Monitoring in Urban Soils-Laboratory and Field Calibration

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6510
Author(s):  
Tala Kanso ◽  
Marie-Christine Gromaire ◽  
David Ramier ◽  
Philippe Dubois ◽  
Ghassan Chebbo
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Urban Soils ◽  
Sandy Loam ◽  
Calibration Method ◽  
Volumetric Water Content ◽  
Calibration Data ◽  
Undisturbed Soil ◽  
Field Calibration ◽  
Calibration Methods

Recently, emphasis has been placed on finding a reliable estimation of soil water content. In this study, two capacitance sensors EC5 and 5TE (METER Group) were utilized. These sensors provide many benefits relative to other sensors in that they are cost-effective and very economical regarding energy use, operate at a high measurement frequency of 70 MHz, and are dedicated to measuring at a small volume because of their small size. This makes them suitable for the context of use in this research, which consists of multiple sustainable drainage systems SuDS. Several studies have evaluated these two types of sensor but not for urban soils with specific characteristics. In addition, results from the literature are divergent and the published calibration data are limited. Therefore, an in-depth investigation of their accuracy is assessed in this paper. At first, the literature’s existing procedures and methods were examined. The sensor-to-sensor variability, as well as repeatability, were tested in soil and solutions. Additionally, a field calibration method was conducted to estimate the effects of soil texture on sensors readings. Two laboratory calibration methods having different principles were also applied, compared to each other and to the field calibration as well. Results revealed weak sensor-to-sensor variability (coefficient of variation up to 15% in soil) and also good repeatability (0.1%), for both sensors. A soil-specific calibration equation has improved the estimation of the volumetric water content. In case of soil having high field bulk density, the undisturbed soil calibration method described and proposed in this paper gives promising results. The latter method yields a volumetric water content (VWC) prediction accuracy of 0.025 m3∙m−3 on a sandy loam soil. This paper presents a large knowledge of capacitance sensors measurement technique as well as their calibration procedures and methods. Limitations of existing procedures have been identified and key elements for selecting the appropriate one are suggested. Derived calibration equations have also been provided for three urban soils with different particle size distribution, ranging from sandy loam to silt loam. Accurate monitoring of soil moisture content in urban soils is thus achievable.

scholarly journals Soil Moisture Estimate Uncertainties from the Effect of Soil Texture on Dielectric Semiempirical Models

2020 ◽  
Vol 12 (14) ◽  
pp. 2343
Author(s):  
Jing Liu ◽  
Qinhuo Liu
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Soil Texture ◽  
Dielectric Behavior ◽  
Volumetric Water Content ◽  
Frequency Range ◽  
Dielectric Model ◽  
Texture Effect ◽  
Semi Empirical ◽  
Semiempirical Models

Soil texture has been shown to affect the dielectric behavior of soil over the entire frequency range. Three universally employed dielectric semiempirical models (SEMs), the Dobson model, the Wang–Schmugge model and the Mironov model, as well as a new improved SEM known as the soil semi-empirical mineralogy-related-to-water dielectric model (SSMDM), incorporate a significant soil texture effect in different ways. In this paper, soil moisture estimate uncertainties from the effect of soil texture on these four SEMs are systematically and widely investigated over all soil texture cases at different frequencies between 1.4 and 18 GHz for volumetric water content levels between 0.0 and 0.4 m3/m3 from the perspective of two aspects: soil dielectric model discordance and soil texture discordance. Firstly, the effect of soil texture on these four dielectric SEMs is analyzed. Then, soil moisture estimate uncertainties due to the effect of soil texture are carefully investigated. Finally, the applicability of these SEMs is discussed, which can supply references for their choice. The results show that soil moisture estimate uncertainties are small and satisfy the 4% volumetric water content retrieval requirement in some cases. However, in other cases, it may contribute relatively significant uncertainties to soil moisture estimates and correspond to a difference that exceeds the 4% volumetric water content requirement, with potential for the largest deviations to exceed 0.22 m3/m3.

Bacterial leaching from dairy shed effluent applied to a fine sandy loam under irrigated pasture

Soil Research ◽  
2008 ◽  
Vol 46 (7) ◽  
pp. 552 ◽  
Author(s):  
Shuang Jiang ◽  
Graeme D. Buchan ◽  
Mike J. Noonan ◽  
Neil Smith ◽  
Liping Pang ◽  
...  
Keyword(s):  
Water Content ◽  
Water Flow ◽  
Sandy Loam ◽  
Volumetric Water Content ◽  
Faecal Coliform ◽  
Bacterial Transport ◽  
Flood Irrigation ◽  
Bacterial Leaching ◽  
Fine Sandy Loam ◽  
Spray Irrigation

This experiment investigated bacterial transport from land-applied dairy shed effluent (DSE), via field lysimeter studies, using 2 contrasting irrigation methods. Transient water flow and bacterial transport were studied, and the factors controlling faecal coliform (FC) transport are discussed. Two trials (Trial 1, summer; Trial 2, autumn) were carried out, using 6 undisturbed soil monolith lysimeters, 500 mm diameter by 700 mm deep, with a free-draining, Templeton fine sandy loam. DSE with inert chemical tracers was applied at the start of both trials using the same method, followed with repeated 14-day cycles of either flood or spray irrigation of water. A bacterial tracer, antibiotic-resistant faecal coliform, was added to the DSE in Trial 2 only, to distinguish applied FC from external or resident FC. Leachates were collected after each water application (or heavy rainfall when applicable) for enumeration of FC and measurement of tracers. All lysimeters were instrumented for monitoring volumetric water content, matric potential, and soil temperature at 4 depths (100, 250, 450, and 600 mm). The results showed that bacteria could readily penetrate through 700-mm-deep soil columns, when facilitated by water flow. The highest post-water irrigation concentration was 3.4 × 103 cfu/100 mL under flood irrigation, which resulted in more bacterial and Br– leaching than spray irrigation. Trial 2 (autumn) results also showed significant differences between irrigation treatments in lysimeters sharing similar drainage class (moderate or moderately rapid), flood irrigation again gave more bacterial and tracer (Cl–) leaching. In the summer trial, FC in leachate as high as 1.4 × 106 cfu/100 mL, similar to the concentration of DSE, was detected in one lysimeter that had a higher clay content in the topsoil immediately after DSE application, and before any water irrigation. This indicates that applied DSE leached through preferential flow paths without any dilution. Bacterial concentration in the leachate was positively correlated with both volumetric water content and water potential, and sometimes drainage rate. Greater bacterial leaching was found in the lysimeter with rapid whole-column effective hydraulic conductivity, Keff, for both flood and spray treatments. Occasionally, the effect of Keff on water movement and bacterial transport overrode the effect of irrigation. The ‘seasonal condition’ of the soil (including variation in initial water content) also influenced bacterial leaching, with less risk of leaching in autumn than in summer. These findings contribute to our increased understanding of bacterial transport processes on the field scale.

scholarly journals Soil Structure and Texture Effects on the Precision of Soil Water Content Measurements with a Capacitance- Based Electromagnetic Sensor

2020 ◽  
Vol 63 (1) ◽  
pp. 141-152
Author(s):  
Jasreman Singh ◽  
Derek M. Heeren ◽  
Daran R. Rudnick ◽  
Wayne E. Woldt ◽  
Geng Bai ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Sensor Calibration ◽  
Soil Water Depletion ◽  
Undisturbed Soil ◽  
Water Depletion ◽  
Soil Moisture Sensors ◽  
Electromagnetic Sensor

HighlightsCapacitance-based electromagnetic soil moisture sensors were tested in disturbed and undisturbed soils.The uncertainty in estimation of soil water depth was lower using the undisturbed soil sample calibrations.The uncertainty in estimation of soil water depletion was lower than the uncertainty in volumetric water content.Undisturbed calibration of water depletion quantifies water demand with better precision and avoids over-watering.Abstract. The physical properties of soil, such as structure and texture, can affect the performance of an electromagnetic sensor in measuring soil water content. Historically, calibrations have been performed on repacked samples in the laboratory and on soils in the field, but little research has been done on laboratory calibrations with intact (undisturbed) soil cores. In this study, three replications each of disturbed and undisturbed soil samples were collected from two soil texture classes (Yutan silty clay loam and Fillmore silt loam) at a field site in eastern Nebraska to investigate the effects of soil structure and texture on the precision of a METER Group GS-1 capacitance-based sensor calibration. In addition, GS-1 sensors were installed in the field near the soil collection sites at three depths (0.15, 0.46, and 0.76 m). The soil moisture sensor had higher precision in the undisturbed laboratory setup, as the undisturbed calibration had a better correlation [slope closer to one, R2undisturbed (0.89) > R2disturbed (0.73)] than the disturbed calibrations for the Yutan and Fillmore texture classes, and the root mean square difference using the laboratory calibration (RMSDL) was higher for pooled disturbed samples (0.053 m3 m-3) in comparison to pooled undisturbed samples (0.023 m3 m-3). The uncertainty in determination of volumetric water content (?v) was higher using the factory calibration (RMSDF) in comparison to the laboratory calibration (RMSDL) for the different soil structures and texture classes. In general, the uncertainty in estimation of soil water depth was greater than the uncertainty in estimation of soil water depletion by the sensors installed in the field, and the uncertainties in estimation of depth and depletion were lower using the calibration developed from the undisturbed soil samples. The undisturbed calibration of soil water depletion would determine water demand with better precision and potentially avoid over-watering, offering relief from water shortages. Further investigation of sensor calibration techniques is required to enhance the applicability of soil moisture sensors for efficient irrigation management. Keywords: Calibration, Capacitance, Depletion, Irrigation, Precision, Sensor, Soil water content, Structure, Uncertainty.

scholarly journals Calibration of a soil moisture sensor with disturbed and undisturbed soil samples from Bahia

2018 ◽  
Vol 22 (10) ◽  
pp. 696-701
Author(s):  
João G. A. Lima ◽  
Aureo S. de Oliveira ◽  
Luciano da S. Souza ◽  
Neilon D. da Silva ◽  
Paula C. Viana
Keyword(s):  
Soil Moisture ◽  
Soil Samples ◽  
Calibration Data ◽  
Undisturbed Soil ◽  
Moisture Sensor ◽  
Soil Moisture Sensor ◽  
Disturbed Soil ◽  
Undisturbed Samples ◽  
Three Samples ◽  
Quadratic Models

ABSTRACT The objective of this study was to evaluate the models proposed by manufacturers and in the literature with respect to soil moisture measurement and to evaluate the performance of the CS616 sensor in the calibration of disturbed and undisturbed soil samples. These calibrations were performed using linear and quadratic models. Disturbed samples were collected in São Gabriel/BA, six samples placed in pots, whereas undisturbed samples were collected in Cruz das Almas/BA, three samples directly collected in the area and placed in a container. A calibration was performed between 21/12/2016 and 08/01/2017. The models proposed in the literature and by manufacturers differed in the estimation of volumetric soil moisture. Disturbed soil samples had higher data dispersion than undisturbed samples, due to factors such as grain size and bulk density, which influence the calibration data. The CS616 sensor had satisfactory performance in the calibration of disturbed and undisturbed samples, with excellent fit of the soil moisture data. Using soil moisture contents obtained by the CS616 sensor, without a previous calibration, may lead to errors in the results, confirming the need for a specific calibration for each type of soil.

Field calibration of a capacitance soil water probe in heterogeneous fields

Soil Research ◽  
2004 ◽  
Vol 42 (3) ◽  
pp. 289 ◽  
Author(s):  
Dieter Geesing ◽  
Martin Bachmaier ◽  
Urs Schmidhalter
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Samples ◽  
Soil Conditions ◽  
Site Specific ◽  
Field Calibration ◽  
Calibration Methods ◽  
Significant Difference ◽  
Capacitance Probe

Soil water research requires methods to perform accurate measurements. A capacitance probe gauge has characteristics that seem to make it an attractive replacement for neutron scatter gauges to measure soil water content, but there is evidence that capacitance systems should be calibrated for individual soils. Laboratory calibrations and many field calibration methods are costly and time-consuming, and controlled conditions and disturbed soil samples do not always reflect field conditions, and thus, they are inadequate for practical use. The objectives of the present study were (i) to test a simple field calibration method for a recently developed capacitive sensor even under highly variable soil texture conditions, and (ii) to validate this approach under various soil moisture conditions. Soil samples were taken 0.5 m from the access tube of the sensor and a whole field calibration and several site-specific calibrations were developed using 10–142 observations per site under different soil water regimes. A regression of soil water content estimated by sensor reading on water content obtained by core sampling showed no significant difference in the slope and intercept of the 1:1 line when the field calibration was applied. However, the precision of the calibration was only considerably increased if the estimations were based on site-specific calibrations developed on at least 35 observations per site. The precision and accuracy of the calibration equations were not affected when data were obtained only under wet or dry soil conditions. The method presented in this paper is a speedy and cheap way to calibrate capacitance probe sensors.

scholarly journals Drought stress tolerance of two wheat genotypes

2008 ◽  
Vol 3 (Special Issue No. 1) ◽  
pp. S95-S104 ◽  
Author(s):  
A. Lukács ◽  
G. Pártay ◽  
T. Németh ◽  
S. Csorba ◽  
C. Farkas
Keyword(s):  
Soil Moisture ◽  
Drought Stress ◽  
Water Balance ◽  
Water Content ◽  
Stress Tolerance ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Columns ◽  
Undisturbed Soil ◽  
Wheat Genotypes

Biotic and abiotic stress effects can limit the productivity of plants to great extent. In Hungary, drought is one of the most important constrains of biomass production, even at the present climatic conditions. The climate change scenarios, developed for the Carpathian basin for the nearest future predict further decrease in surface water resources. Consequently, it is essential to develop drought stress tolerant wheat genotypes to ensure sustainable and productive wheat production under changed climate conditions. The aim of the present study was to compare the stress tolerance of two winter wheat genotypes at two different scales. Soil water regime and development of plants, grown in a pot experiment and in large undisturbed soil columns were evaluated. The pot experiments were carried out in a climatic room in three replicates. GK Élet wheat genotype was planted in six, and Mv Emese in other six pots. Two pots were left without plant for evaporation studies. Based on the mass of the soil columns without plant the evaporation from the bare soil surface was calculated in order to distinguish the evaporation and the transpiration with appropriate precision. A complex stress diagnosis system was developed to monitor the water balance elements. ECH<sub>2</sub>O type capacitive soil moisture probes were installed in each of the pots to perform soil water content measurements four times a day. The irrigation demand was determined according to the hydrolimits, derived from soil hydrophysical properties. In case of both genotypes three plants were provided with the optimum water supply, while the other three ones were drought-stressed. In the undisturbed soil columns, the same wheat genotypes were sawn in one replicate. Similar watering strategy was applied. TDR soil moisture probes were installed in the soil at various depths to monitor changes in soil water content. In order to study the drought stress reaction of the wheat plants, microsensors of 1.6 mm diameter were implanted into the stems and connected to a quadrupole mass spectrometer for gas analysis. The stress status was indicated in the plants grown on partly non-irrigated soil columns by the lower CO<sub>2</sub> level at both genotypes. It was concluded that the developed stress diagnosis system could be used for soil water balance elements calculations. This enables more precise estimation of plant water consumption in order to evaluate the drought sensitivity of different wheat genotypes.

scholarly journals New Soil Property Database Improves Oklahoma Mesonet Soil Moisture Estimates*

2013 ◽  
Vol 30 (11) ◽  
pp. 2585-2595 ◽  
Author(s):  
Bethany L. Scott ◽  
Tyson E. Ochsner ◽  
Bradley G. Illston ◽  
Christopher A. Fiebrich ◽  
Jeffery B. Basara ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Large Scale ◽  
Water Retention ◽  
Soil Property ◽  
Volumetric Water Content ◽  
Water Retention Curve ◽  
Retention Curve ◽  
Soil Moisture Data ◽  
Oklahoma Mesonet

Abstract Soil moisture data from the Oklahoma Mesonet are widely used in research efforts spanning many disciplines within Earth sciences. These soil moisture estimates are derived by translating measurements of matric potential into volumetric water content through site- and depth-specific water retention curves. The objective of this research was to increase the accuracy of the Oklahoma Mesonet soil moisture data through improved estimates of the water retention curve parameters. A comprehensive field sampling and laboratory measurement effort was conducted that resulted in new measurements of the percent of sand, silt, and clay; bulk density; and volumetric water content at −33 and −1500 kPa. These inputs were provided to the Rosetta pedotransfer function, and parameters for the water retention curve and hydraulic conductivity functions were obtained. The resulting soil property database, MesoSoil, includes 13 soil physical properties for 545 individual soil layers across 117 Oklahoma Mesonet sites. The root-mean-square difference (RMSD) between the resulting soil moisture estimates and those obtained by direct sampling was reduced from 0.078 to 0.053 cm3 cm−3 by use of the new water retention curve parameters, a 32% improvement. A &gt;0.15 cm3 cm−3 high bias on the dry end was also largely eliminated by using the new parameters. Reanalysis of prior studies that used Oklahoma Mesonet soil moisture data may be warranted given these improvements. No other large-scale soil moisture monitoring network has a comparable published soil property database or has undergone such comprehensive in situ validation.

scholarly journals Effects of the Soil Moisture Content on the Superoxide Anion and Proline Contents in Soybean Leaves

2021 ◽  
Author(s):  
Zihao Wu ◽  
Xiyue Wang ◽  
Xin Wang ◽  
Chao Yan ◽  
Chunmei Ma ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Water Content ◽  
Superoxide Anion ◽  
Soil Moisture Content ◽  
Volumetric Water Content ◽  
Drought Tolerant ◽  
Soybean Plants ◽  
Feed Protein ◽  
Soybean Leaves

Background: As an important source of feed protein, soybean is involved in the processing industry, food industry and other fields. Therefore, in recent years, the demand for soybean has increased and soybean planting areas have also increased. However, frequent droughts have a serious impact on soybean yield. Methods: During the flowering period, the soybean plants were subjected to drought treatments of different degrees (0-7 days without water). The superoxide anion and proline contents in the leaves were determined. Then, fitting curves were drawn between the soil moisture content and the superoxide anion and proline contents. Result: The effects of different soil moisture contents on the superoxide anion and proline contents in soybean leaves and the correlation between these contents were analyzed. According to the fitting curves, with a decrease in the volumetric water content of soil, the superoxide anion and proline contents in soybean leaves increased. The superoxide anion contents in drought-tolerant cultivars were significantly lower than those in drought-sensitive cultivars and the proline contents were significantly higher in drought-tolerant cultivars than those in drought-sensitive cultivars. The superoxide anion content in soybean leaves was positively correlated with the proline content in the soil volumetric water content range of 31.5% to 14.5%.

scholarly journals Solute Transport Measurements in Different Soil Types using Time Domain Reflectometry

2001 ◽  
Vol 32 (2) ◽  
pp. 99-114 ◽  
Author(s):  
Magnus Persson
Keyword(s):  
Solute Transport ◽  
Time Domain ◽  
Calibration Method ◽  
Calibration Procedure ◽  
Solute Concentration ◽  
Time Domain Reflectometry ◽  
Soil Types ◽  
Undisturbed Soil ◽  
Transport Measurements ◽  
Calibration Methods

During recent years, time domain reflectometry (TDR) has proved to be a valuable tool for both water content (θ) and bulk electrical conductivity (σa) measurements. To allow resident solute concentration (Cr) measurements, a calibration procedure is necessary for the relationship between σa and Cr. Two main calibration approaches exist. Direct calibration allows for Cr measurements with varying θ, while the indirect calibration method is used for conditions with constant θ. In this paper, three methods of achieving direct calibration parameters are presented and evaluated in three different soil types. Calibrations are made in both disturbed and undisturbed soil columns as well as in the field. It was shown that there were only small differences between calibration methods in homogeneous sand. In other soils, choosing the correct calibration is important. In clay soils solute transport measurements are difficult to take under conditions with varying θ, therefore it is suggested that only the indirect calibration approach should be used. When using TDR it is important to be aware of the accuracy of the TDR system in order to interpret data correctly. Some error sources are thus also briefly discussed.

Sign in / Sign up

Export Citation Format

Share Document