Speaker
Description
The study of mass transport in porous media is central to many environmental and engineering applications, including hydrogeology, energy systems, and agriculture. In the context of sustainable agriculture, conventional fertilizers often suffer from low efficiency due to a significant mismatch between the timescale of nutrient transport in soil and the timescale of plant uptake, leading to nutrient losses and environmental harm in soil and subsurface environments. Controlled-release fertilizers (CRFs) aim to reduce these losses by delaying nutrient release into the surrounding soil. However, their performance depends critically on understanding transport processes occurring from the fertilizer granule into the surrounding porous medium, particularly at the interface scale.
The modeling of fertilizer transport in soil involves complex interactions between fluid flow, porous structure heterogeneity, and chemical transport processes. Despite extensive experimental studies, mechanistic modeling laws that describe nutrient release and transport in soil are still limited and are often empirical or case-specific, making them difficult to integrate consistently into standard transport equations. Furthermore, existing macroscopic models frequently represent nutrient release as a volumetric soil source, which fails to capture the localized nature of release at the fertilizer–soil interface and can lead to inaccuracies in mass conservation and numerical stability. On the other hand,, classical fluid dynamics models, while rigorous for free-flow systems, struggle to represent the nonlinear dependence of transport parameters on pore geometry and medium characteristics.
In this work, we propose a modeling and numerical framework that explicitly accounts for the interfacial nature of nutrient release from CRFs. We show that nutrient release must be modeled as a localized exchange process at the granule boundary rather than as a volumetric source term. Based on this observation, we derive a mechanistic interface exchange law governing nutrient transfer from the fertilizer surface into the surrounding porous medium. This law is incorporated into a coupled transport model describing diffusion- and advection-driven nutrient migration in soil, resulting in an advection–diffusion–reaction formulation with interface exchange terms.
Our coupled system is then formulated in a variational setting to provide a consistent framework for stability analysis, mass conservation, and finite element discretization. We employed interface-resolved meshes to represent the exchange terms accurately at the discrete level. We investigate the influence of geometric resolution, discretization choices, and parameter regimes on numerical stability and mass conservation. A non-dimensionalization of the governing equations is also used to identify transport regimes and transitions between advection-dominated and diffusion-dominated behavior. This framework enables the investigation of how pore-scale geometry and interface processes influence effective transport behavior at the continuum scale.
The analysis remains directly connected to agriculturally motivated soil transport case studies.
| Country | Morocco |
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