Content

Lectures on theory and modeling techniques (half of the time):

1. Water flow
-   Review of basic concepts: water potential, water retention, hydraulic conductivity, Darcy-Buckingham equation, Richards equation
-   Numerical solution of Richards equation, boundary and initial conditions
-   Soil water budget, root water uptake, atmospheric feedback, coupling of soil water models to crop models
-   Preferential flow, soil heterogeneity, 2D and 3D flow
 
2. Microbial transformation processes in soils
-   First-order and Monod kinetics
-   Nitrogen cycle in soils
-   Pesticide degradation in soils; reaction chains
-   Dependence of reaction rates on soil temperature and soil moisture content
 
3. Solute transport in soils
-   Review of basic concepts: convection, diffusion, hydrodynamic dispersion
-   Convection-dispersion equation
-   Sorption and retardation; application to pesticide leaching
 
4. Heat flow in soils.
-   Review of basic concepts: energy balance of the soil surface, soil thermal properties
-   Soil heat flux
-   Soil temperature regime
 
5. Estimation of parameters in soil water models
-   Pedotransfer functions for estimating parameters from easy-to-measure soil properties
-   Direct measurement of soil properties
-   Inverse modeling; local and global search methods (optimization)
 
Practical exercises (working with the Hydrus model software; half of the time):

The lectures are integrated with a series of guided exercise sessions (on student laptops) in the collaborative classroom.  In this classroom, the students will use the public-domain soil-water model HYDRUS-1D to simulate several simple cases of transport of water, heat, and solutes in soils: water infiltration, water balance of a cropped soil, soil thermal regime, solute leaching in soil columns, leaching of nitrogen fertilizer and pesticides in soils. Through the exercises, insight is gained into how the flow of water, heat and solutes and the solute transformation processes are interlinked, and how these processes can be simulated in an integrated way with the HYDRUS-1D model. Towards the end of the semester, students will also work on their laptops with the 3D version of the model (for which we have a group license).  This will allow simulating 2D flow and transport problems typically arising when the unsaturated zone and the saturated zone are considered together (e.g. when solutes like nitrate are leached from the root zone to the phreatic groundwater and further transported horizontally to a nearby ditch or river).

Course material

See Toledo

Format: more information

26 hrs/2 credits theory; 26 hrs/2 credits of practical work; 26 hrs/1 credit of assignment/guided self-study