A Pore Water Conductivity Sensor

Hilhorst, M.A.

doi:10.2136/sssaj2000.6461922x

Cited by 227 publications

(223 citation statements)

References 5 publications

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“…Las lecturas de la CE se realizaron con una sonda Tetracon 325 (WTW, Weilheim, Alemania). También se midió la conductividad eléctrica aparente del suelo (CE b ) en continuo a 15 cm de profundidad con un sensor capacitivo 5TE (Decagon Devices), transformando la lectura de la constante dieléctrica del medio con la ecuación de Hilhorst (Hilhorst 2000) y esta se convirtió a la conductividad eléctrica del extracto a saturación (CE s ) en dS/m mediante la siguiente relación:…”

Section: -Objetivosunclassified

Dinámica Del Agua en El Suelo, Productividad Del a Gua Y Economia en Riego Por Inundación Y Goteo en Arroz

Arbat¹,

Parals²,

Duran–Ros³

et al. 2018

XXXVI Congreso Nacional De Riegos

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ResumenEl arroz regado por inundación continua (RIC) es uno de los cultivos que necesita más agua, por lo que, en un contexto donde el agua puede ser limitante, tiene interés explorar la posibilidad de buscar métodos de riego que utilicen menos agua, tales como el riego por goteo (RG). En el presente trabajo se ha realizado un seguimiento en dos campos, uno RIC y el otro por RG. En ambos campos se midió el agua aportada por riego y por la lluvia, el contenido de agua en el suelo a distintas profundidades y la profundidad del freático. Se realizó un seguimiento del cultivo y de la conductividad eléctrica del agua de riego, del suelo y del freático. El modelo HYDRUS-1D se utilizó para simular la dinámica de agua en el suelo y el agua que drenó. Finalmente, se determinó la producción de arroz en grano. Los resultados muestran que la productividad del agua se incrementó de 0,42 kg/m 3 en RIC a 0,60 kg/m 3 en RG, lo que representa un incremento del 30%, por lo que el RG podría tener interés en situaciones donde el agua es un factor limitante. Sin embargo, el RG redujo el agua que drenó en profundidad e incrementó la CE del suelo y del agua de drenaje. Además, el RG no resultó viable económicamente, fundamentalmente por los costes inherentes al sistema de riego. El RG en arroz es una técnica innovadora de la que existe actualmente muy poco conocimiento y de la cual estos ensayos son pioneros. Es necesario avanzar en el estudio del RG para determinar el alcance de su aplicabilidad y sostenibilidad. AbstractContinuous flooded rice (RIC) is one of the crops that needs more water, therefore in a context where water can be limiting factor, it is required to study irrigation methods that require less water, such as drip irrigation (RG). In the present field study a follow up of two fields, one RIC and the other RG, were carried out. Irrigation water, rainfall, soil water contents at different soil depths and ground water levels, as well as electrical conductivity of irrigation water, soil and ground water were regularly monitored along the irrigation campaign. HYDRUS-1D model was used to simulate soil water dynamics and drained water.

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Section: -Objetivosunclassified

Dinámica Del Agua en El Suelo, Productividad Del a Gua Y Economia en Riego Por Inundación Y Goteo en Arroz

Arbat¹,

Parals²,

Duran–Ros³

et al. 2018

XXXVI Congreso Nacional De Riegos

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“…On the other hand, we can treat dielectric constant as the imaginary part of complex electrical conductivity (Sihvola, 1999). This implies that soil apparent dielectric constant and bulk soil electrical follows similar rules (White et al, 1994;Hilhorst, 2000). By this analogy, a calibration relationship for bulk soil electrical conductivity should be similar to that for soil apparent dielectric constant and can be expressed as:…”

Section: Calibration Relationship For Bulk Soil Electrical Conductivitymentioning

confidence: 99%

Beta Testing Implementation of the Purdue Time Domain Reflectometry (TDR) Method for Soil Water Content and Density Measurement

Drnevich¹,

Yu²,

Lovell³

2003

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Prepared in cooperation with the Indiana Department of Transportation and Federal Highway Administration. AbstractThe Purdue TDR method is a new technology for simultaneously measuring soil water content and dry density insitu. An ASTM standard for using TDR to measure soil water content and dry density based on Purdue TDR method was approved during the time span of this project and is designated ASTM D6780. The primary objective of this study was to take the Purdue TDR Method to the point where it is widely field tested by users on a broad spectrum of soils around the country. This goal was achieved by involving researchers at other universities and practitioners in federal and state agencies and in private practice firms. The results and feedback was obtained from Beta Partners by Purdue University for evaluation and further analysis. Major achievements in this research include: 1) Involvement of Beta Partners -Six Beta partners including two universities, two private firms and two state DOTs were involved in this project and instructions were provided to each Beta Partners. Involving these Beta partners provided a large span of field applications and research feedback.Results from testing performed were compared with existing technologies and provided the basis for the precision and bias statements needed for ASTM D6780. Based on feedback from extensive field tests, testing procedures were improved. Meanwhile, the testing equipment was refined and integrated, which made the testing system both more robust and easier to handle. The overall cost of the testing system has also been significantly reduced, which made it more economically competitive for mass production. 2) Testing automation -A new generation of electronics was identified and incorporated into the Purdue TDR test, the new TDR100 by Campbell Scientific, Inc. Corresponding software for automation was designed and systematically improved. This provided a user friendly interface and facilitated performance of TDR testing process. Preliminary feedback from using the computer software is satisfactory. The efforts and achievements on testing automation also built up the basis for a developing a more compact package in the future. 3) One step method for TDR testing -A simplified procedure to that described by ASTM D6780 to measure soil water content and dry density was discovered, which is an important product of this project. The simplified procedure is called the one-step method since it only requires one field TDR reading. The one-step method achieved this simplification by incorporating information of bulk electrical conductivity from TDR signal in addition to the apparent dielectric constant used by previous TDR test. A scheme to account for the difference between field conditions and laboratory situations was developed, which serves as the basis of the one step method. A simplified temperature compensation scheme was also designed which makes it possible for the one-step method to deal with complex field situations. Computer software was developed t...

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“…Equation (4) was not more adequate than the Hilhorst's model (Hilhorst, 2000), which was applied using multiple values for the constant ε σ=0 between 3 and 10 (6.2 is the value used for the fit line in Fig. 6 Recently, in a study on the performance of WET ® sensor in volcanic soil, Regalado et al (2007) found that the empirical relationships between σ P and σ was better described by the Vogeler et al (1996) model than by Hilhorst's model.…”

Section: Resultsmentioning

confidence: 99%

The Calibration of Wet-Sensor for Volumetric Water Content and Pore Water Electrical Conductivity in Different Horticultural Substrates

Incrocci¹,

Incrocci²,

Pardossi³

et al. 2009

Acta Hortic.

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A frequency domain dielectric sensor (WET ® ), which measures permittivity (ε), temperature (T, °C) and bulk electrical conductivity (σ, dS/m) simultaneously in the same soil volume, was calibrated for the volumetric water content (θ, m 3 m -3 ) and the salinity of both pore water (σ P ) and water extract (σ E ) in different horticultural substrates: peat, pumice, perlite, peat-perlite and peat-pumice. The experiment was conducted under laboratory conditions over a T range between 22 and 28°C using plastic pots filled with each substrate, irrigated to fully container capacity with nutrient solutions of known concentrations and let to dry (in air) to θ ranging from approx. 0.20 and 0.50 m 3 m -3 . In order to avoid the development of significant gradients in substrate moisture and salinity, the pots did not host plants and the evaporation from the top surface was prevented by means of a plastic wrap. Pore water was collected by centrifugation, whereas water extract was obtained by means of 1 substrate: 2 water suspension method. The values of both ε and σ were corrected for T. The main results of the experiment are the following: i) θ calibration was faintly dependent on the type of substrate and was only slightly affected by the salinity of irrigation water; ii) a significant linear relationship was found between σ E and σ P , with the slope dependent on the type of substrate; iii) the linear relationship of ε against θ was highly significant and unaffected by the salinity of irrigation water; iv) at least in the peat-pumice mixture, the only substrate used for this kind of calibration, the linear regression between σ and σ P was markedly affected by θ, since the slope decreased with increasing θ. INTRODUCTIONWith respect to soil culture, container-grown plants necessitate much more water and fertilisers and, due to the widespread practice for growers to overirrigate their plants, the environmental impact in term of water use and nutrient leaching through runoff may be considerable. Therefore, a precise control of irrigation and fertigation is necessary and this, evidently, requires an accurate estimation of plant evapotranspiration. A possible approach to efficient irrigation management entails the use of root zone sensors to regulate the frequency and, possibly, the water dose by monitoring continuously the tension or the volumetric water content (θ, m 3 m -3 ) of growing media. In the recent past, a new generation of dielectric sensors has been developed to be used for the control of irrigation in both soil and soilless culture. These sensors are meant to measure both θ and the salinity (namely, electrical conductivity or EC) of growing media, thus providing the possibility to control the fertilisation as well, for example by adjusting the concentration

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A Pore Water Conductivity Sensor

Cited by 227 publications

References 5 publications

Dinámica Del Agua en El Suelo, Productividad Del a Gua Y Economia en Riego Por Inundación Y Goteo en Arroz

Dinámica Del Agua en El Suelo, Productividad Del a Gua Y Economia en Riego Por Inundación Y Goteo en Arroz

Beta Testing Implementation of the Purdue Time Domain Reflectometry (TDR) Method for Soil Water Content and Density Measurement

The Calibration of Wet-Sensor for Volumetric Water Content and Pore Water Electrical Conductivity in Different Horticultural Substrates

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