Week 5 & 6 - Soil Water Flashcards
A soil, where plant growth was poor, was found to have red colour adjacent to the plant roots in an otherwise grey soil background. Explain the cause of such an observation within the soil.
Explain the changes that can occur to soil nitrogen availability when a soil becomes waterlogged.
Complete the following information by naming the driving force and direction of water movement in saturated and unsaturated conditions:
a) Saturated
b) Unsaturated
a) Gravity & Downward
b) Matric potential & Depends on the direction of the potential gradient arising from total water potential components other than gravity
What atmospheric factors influence the evaporation of soil water?
i. the input of energy into the system. The main source of heat energy for evaporation is solar radiation;
ii. the capacity of air to absorb the water. The capacity for air to take up water vapour increases with its dryness (low humidity);
iii. wind to remove the water vapour from the surface. Air above the soil can become saturated. Further evaporation depends on wind to move the saturated air away, so evaporation increases with wind velocity.
List the soil properties that influence the water holding capacity of a soil.
A soil was found to have a bluish/green colour. Explain the cause of the soil colour observed.
List the soil properties that influence the water holding capacity of a soil.
What would you use to measure soil water potential in an irrigated field?
Describe this piece of equipment.
Describe how this piece of equipment performs its operation.
Describe a negative aspect of the piece of equipment.
What atmosphere factors influence evaporation of soil water.
What is the water potential of the following moisture contents:
- Unsaturated
- Field capacity
- Saturated
Rank the rate of infiltration of water (fast /medium /slow) for each of the 4 soils:
- Sand & Massive
- Sandy Loam & Massive
- Heavy Clay & Massive
- Heavy Clay & Granular
