1. If the flux of evaporation increases, what will happen with the full capillary zone?

   • A. Increase
   • B. Decrease
   • C. Remain the same (Show mathematically)

2. Bulk density can be used as an indicator of soil health. However, for clay soils, a correction needs to be made. Explain why.

3. True or false: When a soil dries out, the flux of water will change linearly. Explain.

4. Given are graphs of rainfall, soil moisture, and matric potential. At two different times (in a dry period and in a wet period), the soil has two different matric potentials, but the same soil moisture content.

   • How is this possible?
   • Give 3 reasons why this happens (explain with graphs and equations).

5. Capacitance sensor:

   • A photo of a capacitance sensor is given. On which principle does this device work and how can we use the measured values to calculate the matric potential?
   • Can we monitor the air content of the soil with the given measurements if you know that the bulk density is $\rho_b = 1.46\text{ Mg/m}^3$?

6. A tensiometer is placed in the ground at a depth of $-10\text{ cm}$ (above the water table).

   • a. Calculate the hydraulic head at the water table (depth: $-60\text{ cm}$).
   • b. Calculate the pressure you will read on the tensiometer (formula given).
   • c. Calculate the soil moisture content at $-10\text{ cm}$ (Van Genuchten equation with parameters is given).
   • d. Calculate the gravimetric water content / potential at $-10\text{ cm}$.

7. Steady-state flow exercise: A steady-state flow setup has $5\text{ cm}$ of water ponding on top of a soil column, and the groundwater table is located at $-60\text{ cm}$.

   • a. Calculate the flux $q$ ($K_s$ is given).
   • b. Draw the curves for gravitational head, pressure head (hydrostatic), and total hydraulic head from $+5\text{ cm}$ to $-100\text{ cm}$ (reference level is the soil surface).
   • c. How thick will the full capillary layer be when the downward flux is $2\text{ cm/h}$?

Taak telt mee voor 7 à 8 punten.

Deel Cornelis:

1. Geef oplossingen voor een zure bodem (staat mooi op slides).
2. Oefeningen

Deel Janssens:

• Algemene vragen, geen specifieke formules.