algebraic equation

• actual soil evaporation
• boundary conditions for solute transport
• canopy water balance
• drainage
• soil hydraulic properties in one-domain flow
• solute concentration in canopy and rain
• solute loss due to biodegradation
• upper boundary condition for unsaturated water flow
• vertical water flow in saturated zone
• water uptake by roots

dynamic equation

• crop cover
• soil hydraulic properties in two-domain flow

partial differential equation

• bottom boundary condition for unsaturated water flow
• soil temperature
• solute transport
• unsaturated soil water flow