Soils Exam review

In the Soil Plant Atmosphere Continuum (SPAC) water potential in the atmosphere is _____ than water potential at the leaf surface

Less negative

If soil has a lower water potential than the plant roots evapotranspiration can still take place?

No. Water potential goes from less negative (more energy) to more negative (less energy)

A dry atmosphere will result in a faster rate of evapotranspiration compared to a humid atmosphere?

True.

A dryer atmosphere = more negative water potential than a humid atmosphere meaning a faster rate of evapotranspiration

Wind decreases the relative humidity around a plant, increasing evapotranspiration

True

Surface Draining Pros & Cons

Pros:

• large volume of water can be removed (flooding chance low)

• Low installation cost

Cons:

• Takes up a lot of land

• Surface horizontal water movement → erosion → high maintenance cost

Subsurface Draining Pros & Cons

Pros:

• Water travels down into profile → little erosion → little cost to maintenance

Cons:

• Soil is wetted throughout → enhances leaching of fertilizers and pollutants into ground water

• High installation cost

• Slow flow (high chance of flooding)

A horizon souls are more likely to have what than B horizon souls?

• More sand

• Faster vertical drainage

• More organic matter

Which soil texture is more likely to be found in subsurface soils (B horizon) relative to A horizon soils in a well developed soil?

• Silty Clay

• Loam

• Sandy

• Clay loam

• Silt loam

• Silt

Silty clay

Entisols are characterized by?

Recently deposited parent material