Hydrostructural Pedology

Erik Braudeau, Amjad T. Assi, Rabi H. Mohtar

• Publisher: Wiley-ISTE
• Year: 2016
• ISBN:
  9781119318521
• Edition: 1
• Topic: Technologie et ingénierie
• Subtopic: Ingénierie civile

This book presents an in-depth guide to the subject matter and main points of hydrostructural pedology, as theorized for the first time. The authors focus on the underlying concepts, the purpose and role this field plays within agroenvironmental sciences.

It is divided into two parts:

Part 1 presents the theory behind hydrostructural pedology. The systemic approach applied to the soil is presented, showing how this leads to the thermodynamic formulation of water in the soil's organized medium and to the systemic modeling of soil–water-coupling in natural or anthropic organizations.

Part 2 presents the methodology to complement the first part. In it, the authors determine the hydrostructural characteristics of the pedostructure, characteristic parameters of equilibrium state equations and the hydrostructural functioning of the soil.

PART 1
Theory of Systemic Modeling of the Pedostructure within the Hierarchal Hydrofunctional Organization of the Natural Environment

The systemic approach to the natural environment is theorized here, in line with work by Bertalanffy and Le Moigne, accurately defining the notion of system with regard to organization, especially the organization of the natural environment. The concepts associated with “black box” or “Representative Elementary Volume” (REV) used across the board in hydrophysics of the natural environment are questioned and should be replaced by the concept of “structural representative elementary volume” (SREV). We have reformulated the systemic approach of the natural environment according to this new concept to adjust it to soil science (defining a methodology of cartography, characterization, and multi-scale hydrostructural modeling of soils), to link the different nested levels of description of the soil organization without conceptual discontinuity between the “soil medium” below and the natural environment at the soil surface. We will show how the systemic approach based on the concept of SREV provides the conceptual means to transform the organization of the soil medium into an organized thermodynamic system that is closed for solid elements of its internal structure and open for other mobile elements in this structure. This allows access to a thermodynamic formalization of hydrostructural equilibrium within the soil (distribution of water in the soil structure), which varies according to the water content, and to determine exchanges in the soil matrix (in terms of heat, space, water, air, dissolved matter) with the biological sub-systems living within it. We will also show how the schematic representation of the General System (GS) in its three sub-systems (Operating, Information, and Steering) modified according to Le Moigne [LEM 94], is ideal to represent a scientific discipline in the environmental sciences. In this case, its application to soil science reveals a new discipline, hydrostructural pedology, which will be presented in Chapter 5. The Laboratory of Hydrostructural Pedology, equipped with specific equipment recently developed to meet the data measurement and processing demands of the new discipline is described in this part of the book. It is indeed the focal point of the discipline where the physical characterization of the pedostructure of soils is necessary for their interdisciplinary coupling (bio-physical, agricultural etc.) in situ on the field or in laboratory conditions.

1
Introduction to Part 1

Due to the need to implement sustainable agricultural or ecological systems, with an optimized and respectful use of the environment, the Geographical Information System (GIS) is an essential tool for the management and maintenance of these systems. According to Bordin [BOR 02], GIS is an information system of materials, software and processes, designed for the collection, management, manipulation and display of spatial data to solve planning and management problems. In a more general sense, the term GIS describes an information system that integrates, stores, analyzes and displays geographic information (Wikipedia). To play its full role, the GIS cannot simply be a cartographic database of the physical and managed environment. It must also be a three-dimensional information support, needed for the continuous geo-referenced simulation of the hydric functioning of these agricultural or ecological systems whose soil and water are essential components and resources. This allows managers, operators and other stakeholders of the natural environment to act according to the forecasts provided by biophysical models of agricultural production, water consumption, environmental impact, evolution of the system, etc. [DON 10].

However, to support modeling and simulation, GIS should have all relevant information with regard to the physical environment, especially the soil. Is this achievable? What is this relevant information? Soil forms part of the natural soil–plant–atmosphere organization and provides the living and growth space and resources for the plant and all associated biological organisms. The first information layer of the GIS should, therefore, be the mapping units of soils found in the considered zone, similar to the old pedological maps before computers. As we shall see later, there remains the conceptual problem of the typological definition of soils with regard to their hydric and structural functioning. Neither pedology nor hydropedology, a recently created scientific discipline intended to solve this problem [LIN 06, LIN 12], has provided a solution.

The lack of a quantitative definition of the characteristics of the hydrostructural functioning of soil associated with the morphological description of its internal organization, prevents pedological cartography due to two longstanding practical questions:

1. 1) which methodology should be adopted for the physical (hydro structural) characterization of the internal organization of the pedon, the representative soil volume of a soil mapping unit, and, correlatively,
2. 2) what are the cartographic delineation criteria for these units in the landscape, as defined by their representative pedon?

These two key questions, still unresolved, keep the pedological cartography in a qualitative and empirical description of the soils of an area or region. The soil map is then unusable as an information system to support the physical modeling (not empirical) of the pedon.

Authors of the project SIRSIT-BVM [BRA 01] began to address this issue by creating a Spatial Reference Information System of Irrigated Soils in Tunisia, with the aim of serving as supporting information for the agronomic modeling that would take into account the physical soil properties [BEL 08]. A new methodology for the mapping and characterization of soil based on concepts derived from the systemic approach and the General System theory presented by Le Moigne [LEM 94], was implemented. New concepts have been laidout, such as that of pedostructure [BRA 01], which is the representative volume of the soil matrix (fabric) in a soil horizon and that of “SIRS-Soils” (Spatial Reference Information System of soils), identified with the Information System (IS) of the General System model (GS) adapted from Le Moigne [LEM 94] to pedology [BRA 01]. An accu...

Table of contents

• Cover
• Table of Contents
• Title
• Copyright
• Preface
• PART 1: Theory of Systemic Modeling of the Pedostructure within the Hierarchal Hydrofunctional Organization of the Natural Environment
• PART 2: Hydrostructural Characterization of Soil Pedostructure
• Conclusion
• Bibliography
• Index
• End User License Agreement