Hydrostructural Pedology WEF

Hydrostructural Pedology is a new paradigm in soil science that grew naturally from the Nexus application of systems theory to soil science by addressing not only the organization of soil in the Research Group landscape (soil mapping), but also the hierarchical internal organization of the soil medium. HYDROSTRUCTURAL

[1] Typosoil® Apparatus (Soil cores represent the pedostructure of soil horizon)

Pedostructure Retention Pedostructure Shrinkage Curve Curve [5] Structural Representative Elementary 10,000 0.95 Volume 8,000 (KAMEL Model) 0.90 6,000 Measured WRC Extended WRC 4,000 Meaured ShC 0.85 Fitted ShC 2,000 ater Retention [hPa] W

0 0.80 AND MODELING

0.00 0.10 0.20 0.30 0.40 0.50 Specific volume [dm3/KgSoil] 0.00 0.10 0.20 0.30 0.40 0.50 CHARACTERIZ A Water Content [KgWater/KgSolid] Water Content [KgWater/KgSolid] [2] Continuous and Simultaneous Measurements of water retention curve (WRC) & soil shrinkage curve (ShC) TION SCALING, MAPPING

[3] Extracting the hydro-structural Parameters [4] Hierarchical internal organization of soil (Hydrostructural Characterization) (Pedostructure Concept)

Fig.1. Hydrostructural pedology framework for soil-water modeling using the pedostructure and Structural Representative Elementary Volume (SREV) [KAMEL Model]

Pedostructure is like the motor of the soil, whose fuel is the pedostructural water. The hydrostructural properties of the pedostructure are dependent on the thermodynamic interaction between water and the surface charges of soil particles, organics, and minerals constituting the non-rigid structure of the soil. These thermodynamic interactions can be characterized by four curves: • The pedostructure water retention curve, ℎ=ƒ(Wps), • The pedostructural hydraulic conductivity curve, kps=ƒ(Wps), • The pedostructural shrinkage curve, V̅=ƒ(Wps), • The pedostructural swelling curve, V̅=ƒ(t). In the hydrostructural pedology laboratory we are able to characterize the pedostructural characteristics of each soil horizon and to organize the data in relation to the field operations (soil sampling, mapping, experiments) and the geo- referenced soil information system.

EXPERIMENTAL CONDITIONS Pedostructure Characterization Laboratory Agronomic trials or (Soil Typology) Transfer of information lysimeters from lab to field Lab studies: conditions Modeling at pedon scale Pedostructure, Pedo-climate and biology

Transfer of Transfer of information information and from lab. To materials from GIS of natural field to laboratory Assessment/ Adaptation between organization natural organizations FIELD and modeled systems MODELS

Natural organizations: SIRS-Soils Nested and hydro-functional Agro- environmental System-Expert

Fig.2. The hydrostructural pedology laboratory in relationship with the field (sampling) and the soil mapping (NEO-GIS) for the soil plant atmosphere system modeling

Climate Smart Agricultural Practices Long-term impact of agro-environment practices [Modeling Green and Blue Water Cycles at Global Scale] [Low-quality water irrigation, soil additives, fertilizers]

ATMOSPHERE Axis III Hydro-structural Functioning

How to (Quantitatively) Practice # 1 evaluate the impacts of

our practices on soil LAND performance? Baseline • Wastewater reuse? • Management Practices? Practice # 2 Soil LAKES Ground The key is the linkage Axis I OCEAN Evolution RIVERS (Bedrock) to the soil system - + - + Ground Water organization !! Natural Hierarchical Organization of Soil Medium Axis II [Soil Particles, Pedostructure, Horizon, Pedon] Evapo-transpiration Evaporation Blue Water Green Soil Structure Water Flow [Organization] References: Braudeau, E., and R.H. Mohtar, (2009). Modeling the soil system: Bridging the gap between pedology and soil-water physics. Global Planet. Change J., 67, 51-61, doi: 10.1016/j.gloplacha.2008.12.002. Braudeau, E., R.H. Mohtar (2014), A framework for soil-water modeling using the pedostructure and Structural Representative Elementary Volume (SREV) concepts. Front. Environ. Sci., 2:24. doi:10.3389/fenvs.2014.00024. Braudeau, E., Assi, A.T, and Mohtar R.H. (2016). Pédologie hydrostructurale. Collection Système Terre - Environnement dirigée par André Mariotti. ISTE éditions, April, 2016. pp. 188.

Rabi H. Mohtar [email protected] wefnexus.tamu.edu/research/pedostructure-characterization-lab-2