Hydrostructural Pedology, New Scientific Discipline Allowing for Physical Modelling of ‘Green Water’ Dynamics in the Soil-Plant-Atmosphere System
Erik Braudeau *
Department of Research and Development, VALORHIZ, 1900, Boulevard de la Lironde, PSIII, Parc Scientifique Agropolis, F34980 Montferrier sur Lez., France. AND Department of Biological and Agricultural Engineering, WEF Nexus Research Group, Texas A&M University, 224 Scoates Hall, Mail Stop 2117, College Station, TX, USA.
Hassan Boukcim
Department of Research and Development, VALORHIZ, 1900, Boulevard de la Lironde, PSIII, Parc Scientifique Agropolis, F34980 Montferrier sur Lez., France.
Amjad T. Assi
Department of Biological and Agricultural Engineering, WEF Nexus Research Group, Texas A&M University, 224 Scoates Hall, Mail Stop 2117, College Station, TX, USA.
Rabi H. Mohtar
Department of Biological and Agricultural Engineering, WEF Nexus Research Group, Texas A&M University, 224 Scoates Hall, Mail Stop 2117, College Station, TX, USA.
*Author to whom correspondence should be addressed.
Abstract
Using a new paradigm of soil characterization and modeling in agro environmental sciences, named hydrostructural pedology, we were able to show that the “green water” concept of agronomists corresponds exactly to the pedostructural water concept which was physically defined in this paradigm. The water in the pedostructure of soils is composed of two types of water, named micro and macro, nested one in the other. They are differentiated by their chemical potential related to their position in the pedostructure: inside primary aggregates or outside of them in the interpedal space. A fundamental physics of the pedostructural water could be developed within this new paradigm. Finally, the soil medium can now be considered as the location in which the free water (named also blue water), coming from surface (rainfall, irrigation, etc.) and going down by gravity through the macro pore space of the soil, is partially absorbed by the pedostructure, and becomes then the ‘green water’ of the soil. Soil green water is, in fact, the soil water reserve available to plant roots and subsequently transpired by the plants into the canopy. The soil-water model Kamel®, built according to this new paradigm, is the only model able to physically simulate the opposite dynamic cycles of these two kinds of water (blue and green) within the soil-plant-atmosphere system, their exchanges and equilibrium states according to time, at each depth of the pedon. Important implications about strategy of soil-water characterization, mapping and modeling are given for sustainable development and management of agricultural zones.
Keywords: Systemic approach of soil organizations, systemic soil water modeling, soil hydrostructural characterization;, soil pedostructure, pedostructural water, soil green water, hydrostructural pedology laboratory, soil hydrostructural properties