The Experts below are selected from a list of 153 Experts worldwide ranked by ideXlab platform

Rabi H. Mohtar - One of the best experts on this subject based on the ideXlab platform.

  • soil water thermodynamic to unify water retention curve by pressure plates and tensiometer
    Frontiers in Earth Science, 2014
    Co-Authors: Amjad T. Assi, Erik Braudeau, Gaghik Hovhannissian, Rabi H. Mohtar
    Abstract:

    The pressure plate method is a standard method for measuring the pF curves, also called soil water retention curves, in a large soil moisture range from saturation to a dry state corresponding to a tension pressure of near 1500 kPa. However, the pressure plate can only provide discrete water retention curves represented by a dozen measured points. In contrast, the measurement of the soil water retention curves by tensiometer is direct and continuous, but limited to the range of the tensiometer reading: from saturation to near 70-80 kPa. The two methods stem from two very different concepts of measurement and the compatibility of both methods has never been demonstrated. The recently established thermodynamic formulation of the pedostructure water retention curve, will allow the compatibility of the two curves to be studied, both theoretically and experimentally. This constitutes the object of the present article. We found that the pressure plate method provides accurate measurement points of the pedostructure water retention curve h(W), conceptually the same as that accurately measured by the tensiometer. However, contrarily to what is usually thought, h is not equal to the applied air pressure on the sample, but rather, is proportional to its logarithm, in agreement with the thermodynamic theory developed in the article. The pF curve and soil water retention curve, as well as their methods of measurement are unified in a same physical theory. It is the theory of the soil Medium Organization (pedostructure) and its interaction with water. We show also how the hydrostructural parameters of the theoretical curve equation can be estimated from any measured curve, whatever the method of measurement. An application example using published pF curves is given.

  • Physics of the soil Medium Organization part 2: pedostructure characterization through measurement and modeling of the soil moisture characteristic curves
    Frontiers in Environmental Science, 2014
    Co-Authors: Amjad T. Assi, Erik Braudeau, Joshua Jonathan Oswald Accola, Gaghik Hovhannissian, Rabi H. Mohtar
    Abstract:

    Accurate measurement of the two soil moisture characteristic curves, namely, water retention curve (WRC) and soil shrinkage curve (SSC) is fundamental for the physical modeling of hydrostructural processes in vadose zone. This paper is the application part following the theory presented in part I about physics of soil Medium Organization. Two native Aridisols in the state of Qatar named locally Rodah "raod´ə" soil and Sabkha "săb′kə" soil were studied. The paper concluded two main results: the first one is about the importance of having continuous and simultaneous measurement of soil water content, water potential and volume change. Such measurement is imperative for accurate and consistent characterization of each of the two moisture characteristic curves, and consequently the hydrostructural properties of the soil Medium. The second is about the simplicity, reliability, strength and uniqueness of identifying the characteristic parameters of the two curves. The results also confirmed the validity of the thermodynamic-based equations of the two characteristic curves presented in part I.

  • Physics of the soil Medium Organization part 1: thermodynamic formulation of the pedostructure water retention and shrinkage curves
    Frontiers in Environmental Science, 2014
    Co-Authors: Erik Braudeau, Amjad T. Assi, Hassan Boukcim, Rabi H. Mohtar
    Abstract:

    The equations used in soil physics to characterize the hydro-physical properties of the soil Medium cannot be other than empirical since they do not take into account the multi-scale functional Organization of the soil Medium that is described in Pedology. To allow researching the correct formulation of the physical equations describing the soil Medium Organization and properties, a new paradigm of hydrostructural pedology is being developed. This paradigm is to establish the conceptual link between the classical Pedology and the soil-water physics (hydrostructural characterization and modeling of the soil Medium). The paradigm requires the exclusive use of the concept of Structural Representative Elementary Volume (SREV) instead of the classical Representative Elementary Volume (REV) in any physical modeling of the hydrostructural behavior of the soil Medium and of the links with the biotic or abiotic processes evolving within it. This article presents the development of the physical equations of the shrinkage curve and the soil water retention curve from the thermodynamic point of view according to the new paradigm. The new equations were tested and the theory validated using data of simultaneous measurement of both curves on a cylindrical soil sample (pedostructure). Implications of these results on the physical modeling in agro-environmental sciences are discussed.

Erik Braudeau - One of the best experts on this subject based on the ideXlab platform.

  • soil water thermodynamic to unify water retention curve by pressure plates and tensiometer
    Frontiers in Earth Science, 2014
    Co-Authors: Amjad T. Assi, Erik Braudeau, Gaghik Hovhannissian, Rabi H. Mohtar
    Abstract:

    The pressure plate method is a standard method for measuring the pF curves, also called soil water retention curves, in a large soil moisture range from saturation to a dry state corresponding to a tension pressure of near 1500 kPa. However, the pressure plate can only provide discrete water retention curves represented by a dozen measured points. In contrast, the measurement of the soil water retention curves by tensiometer is direct and continuous, but limited to the range of the tensiometer reading: from saturation to near 70-80 kPa. The two methods stem from two very different concepts of measurement and the compatibility of both methods has never been demonstrated. The recently established thermodynamic formulation of the pedostructure water retention curve, will allow the compatibility of the two curves to be studied, both theoretically and experimentally. This constitutes the object of the present article. We found that the pressure plate method provides accurate measurement points of the pedostructure water retention curve h(W), conceptually the same as that accurately measured by the tensiometer. However, contrarily to what is usually thought, h is not equal to the applied air pressure on the sample, but rather, is proportional to its logarithm, in agreement with the thermodynamic theory developed in the article. The pF curve and soil water retention curve, as well as their methods of measurement are unified in a same physical theory. It is the theory of the soil Medium Organization (pedostructure) and its interaction with water. We show also how the hydrostructural parameters of the theoretical curve equation can be estimated from any measured curve, whatever the method of measurement. An application example using published pF curves is given.

  • Physics of the soil Medium Organization part 2: pedostructure characterization through measurement and modeling of the soil moisture characteristic curves
    Frontiers in Environmental Science, 2014
    Co-Authors: Amjad T. Assi, Erik Braudeau, Joshua Jonathan Oswald Accola, Gaghik Hovhannissian, Rabi H. Mohtar
    Abstract:

    Accurate measurement of the two soil moisture characteristic curves, namely, water retention curve (WRC) and soil shrinkage curve (SSC) is fundamental for the physical modeling of hydrostructural processes in vadose zone. This paper is the application part following the theory presented in part I about physics of soil Medium Organization. Two native Aridisols in the state of Qatar named locally Rodah "raod´ə" soil and Sabkha "săb′kə" soil were studied. The paper concluded two main results: the first one is about the importance of having continuous and simultaneous measurement of soil water content, water potential and volume change. Such measurement is imperative for accurate and consistent characterization of each of the two moisture characteristic curves, and consequently the hydrostructural properties of the soil Medium. The second is about the simplicity, reliability, strength and uniqueness of identifying the characteristic parameters of the two curves. The results also confirmed the validity of the thermodynamic-based equations of the two characteristic curves presented in part I.

  • Physics of the soil Medium Organization part 1: thermodynamic formulation of the pedostructure water retention and shrinkage curves
    Frontiers in Environmental Science, 2014
    Co-Authors: Erik Braudeau, Amjad T. Assi, Hassan Boukcim, Rabi H. Mohtar
    Abstract:

    The equations used in soil physics to characterize the hydro-physical properties of the soil Medium cannot be other than empirical since they do not take into account the multi-scale functional Organization of the soil Medium that is described in Pedology. To allow researching the correct formulation of the physical equations describing the soil Medium Organization and properties, a new paradigm of hydrostructural pedology is being developed. This paradigm is to establish the conceptual link between the classical Pedology and the soil-water physics (hydrostructural characterization and modeling of the soil Medium). The paradigm requires the exclusive use of the concept of Structural Representative Elementary Volume (SREV) instead of the classical Representative Elementary Volume (REV) in any physical modeling of the hydrostructural behavior of the soil Medium and of the links with the biotic or abiotic processes evolving within it. This article presents the development of the physical equations of the shrinkage curve and the soil water retention curve from the thermodynamic point of view according to the new paradigm. The new equations were tested and the theory validated using data of simultaneous measurement of both curves on a cylindrical soil sample (pedostructure). Implications of these results on the physical modeling in agro-environmental sciences are discussed.

Amjad T. Assi - One of the best experts on this subject based on the ideXlab platform.

  • soil water thermodynamic to unify water retention curve by pressure plates and tensiometer
    Frontiers in Earth Science, 2014
    Co-Authors: Amjad T. Assi, Erik Braudeau, Gaghik Hovhannissian, Rabi H. Mohtar
    Abstract:

    The pressure plate method is a standard method for measuring the pF curves, also called soil water retention curves, in a large soil moisture range from saturation to a dry state corresponding to a tension pressure of near 1500 kPa. However, the pressure plate can only provide discrete water retention curves represented by a dozen measured points. In contrast, the measurement of the soil water retention curves by tensiometer is direct and continuous, but limited to the range of the tensiometer reading: from saturation to near 70-80 kPa. The two methods stem from two very different concepts of measurement and the compatibility of both methods has never been demonstrated. The recently established thermodynamic formulation of the pedostructure water retention curve, will allow the compatibility of the two curves to be studied, both theoretically and experimentally. This constitutes the object of the present article. We found that the pressure plate method provides accurate measurement points of the pedostructure water retention curve h(W), conceptually the same as that accurately measured by the tensiometer. However, contrarily to what is usually thought, h is not equal to the applied air pressure on the sample, but rather, is proportional to its logarithm, in agreement with the thermodynamic theory developed in the article. The pF curve and soil water retention curve, as well as their methods of measurement are unified in a same physical theory. It is the theory of the soil Medium Organization (pedostructure) and its interaction with water. We show also how the hydrostructural parameters of the theoretical curve equation can be estimated from any measured curve, whatever the method of measurement. An application example using published pF curves is given.

  • Physics of the soil Medium Organization part 2: pedostructure characterization through measurement and modeling of the soil moisture characteristic curves
    Frontiers in Environmental Science, 2014
    Co-Authors: Amjad T. Assi, Erik Braudeau, Joshua Jonathan Oswald Accola, Gaghik Hovhannissian, Rabi H. Mohtar
    Abstract:

    Accurate measurement of the two soil moisture characteristic curves, namely, water retention curve (WRC) and soil shrinkage curve (SSC) is fundamental for the physical modeling of hydrostructural processes in vadose zone. This paper is the application part following the theory presented in part I about physics of soil Medium Organization. Two native Aridisols in the state of Qatar named locally Rodah "raod´ə" soil and Sabkha "săb′kə" soil were studied. The paper concluded two main results: the first one is about the importance of having continuous and simultaneous measurement of soil water content, water potential and volume change. Such measurement is imperative for accurate and consistent characterization of each of the two moisture characteristic curves, and consequently the hydrostructural properties of the soil Medium. The second is about the simplicity, reliability, strength and uniqueness of identifying the characteristic parameters of the two curves. The results also confirmed the validity of the thermodynamic-based equations of the two characteristic curves presented in part I.

  • Physics of the soil Medium Organization part 1: thermodynamic formulation of the pedostructure water retention and shrinkage curves
    Frontiers in Environmental Science, 2014
    Co-Authors: Erik Braudeau, Amjad T. Assi, Hassan Boukcim, Rabi H. Mohtar
    Abstract:

    The equations used in soil physics to characterize the hydro-physical properties of the soil Medium cannot be other than empirical since they do not take into account the multi-scale functional Organization of the soil Medium that is described in Pedology. To allow researching the correct formulation of the physical equations describing the soil Medium Organization and properties, a new paradigm of hydrostructural pedology is being developed. This paradigm is to establish the conceptual link between the classical Pedology and the soil-water physics (hydrostructural characterization and modeling of the soil Medium). The paradigm requires the exclusive use of the concept of Structural Representative Elementary Volume (SREV) instead of the classical Representative Elementary Volume (REV) in any physical modeling of the hydrostructural behavior of the soil Medium and of the links with the biotic or abiotic processes evolving within it. This article presents the development of the physical equations of the shrinkage curve and the soil water retention curve from the thermodynamic point of view according to the new paradigm. The new equations were tested and the theory validated using data of simultaneous measurement of both curves on a cylindrical soil sample (pedostructure). Implications of these results on the physical modeling in agro-environmental sciences are discussed.

Gaghik Hovhannissian - One of the best experts on this subject based on the ideXlab platform.

  • soil water thermodynamic to unify water retention curve by pressure plates and tensiometer
    Frontiers in Earth Science, 2014
    Co-Authors: Amjad T. Assi, Erik Braudeau, Gaghik Hovhannissian, Rabi H. Mohtar
    Abstract:

    The pressure plate method is a standard method for measuring the pF curves, also called soil water retention curves, in a large soil moisture range from saturation to a dry state corresponding to a tension pressure of near 1500 kPa. However, the pressure plate can only provide discrete water retention curves represented by a dozen measured points. In contrast, the measurement of the soil water retention curves by tensiometer is direct and continuous, but limited to the range of the tensiometer reading: from saturation to near 70-80 kPa. The two methods stem from two very different concepts of measurement and the compatibility of both methods has never been demonstrated. The recently established thermodynamic formulation of the pedostructure water retention curve, will allow the compatibility of the two curves to be studied, both theoretically and experimentally. This constitutes the object of the present article. We found that the pressure plate method provides accurate measurement points of the pedostructure water retention curve h(W), conceptually the same as that accurately measured by the tensiometer. However, contrarily to what is usually thought, h is not equal to the applied air pressure on the sample, but rather, is proportional to its logarithm, in agreement with the thermodynamic theory developed in the article. The pF curve and soil water retention curve, as well as their methods of measurement are unified in a same physical theory. It is the theory of the soil Medium Organization (pedostructure) and its interaction with water. We show also how the hydrostructural parameters of the theoretical curve equation can be estimated from any measured curve, whatever the method of measurement. An application example using published pF curves is given.

  • Physics of the soil Medium Organization part 2: pedostructure characterization through measurement and modeling of the soil moisture characteristic curves
    Frontiers in Environmental Science, 2014
    Co-Authors: Amjad T. Assi, Erik Braudeau, Joshua Jonathan Oswald Accola, Gaghik Hovhannissian, Rabi H. Mohtar
    Abstract:

    Accurate measurement of the two soil moisture characteristic curves, namely, water retention curve (WRC) and soil shrinkage curve (SSC) is fundamental for the physical modeling of hydrostructural processes in vadose zone. This paper is the application part following the theory presented in part I about physics of soil Medium Organization. Two native Aridisols in the state of Qatar named locally Rodah "raod´ə" soil and Sabkha "săb′kə" soil were studied. The paper concluded two main results: the first one is about the importance of having continuous and simultaneous measurement of soil water content, water potential and volume change. Such measurement is imperative for accurate and consistent characterization of each of the two moisture characteristic curves, and consequently the hydrostructural properties of the soil Medium. The second is about the simplicity, reliability, strength and uniqueness of identifying the characteristic parameters of the two curves. The results also confirmed the validity of the thermodynamic-based equations of the two characteristic curves presented in part I.

Zhang Tao - One of the best experts on this subject based on the ideXlab platform.