Soil Test Review 23

When plants, animals, and other organisms die, they break down and become part of the soil. What is this part of the soil called?

• sand
• silt
• clay
• humus

Many plants cannot grow in clay soil. Why is this true?

• Clay soil does not have many nutrients.
• Roots cannot easily push through clay soil.
• Water doesn't drain well through clay.
• All of these choices.

What is a soil problem all farmers face?

• soil hardening
• soil erosion
• soil spoiling
• soil pollution

The layer of soil which the topsoil is found.

• Horizon A
• Horizon B
• Horizon C
• Horizon D or R

Which horizon is made up of partially weathered rocks?

• Horizon A
• Horizon B
• Horizon C
• Horizon D or R

Which horizon is made up of partially weathered rocks?

• Horizon A
• Horizon B
• Horizon C
• Horizon D or R

Which horizon contains clay, silt, minerals, and a little humus?

•  Horizon A
• Horizon B
• Horizon C
• Horizon D or R

Which soil has the greatest permeability or quickest flow?

• sand

• silt

• clay

• humus

Which soil has the least permeability or slowest flow?

• sand

• silt

• clay

• humus

A mixture of sand, silt, and clay is known as __________ and is best for farming or agriculture

• sand

• silt

• clay

• loam