Soil

Which of the following type of soil would allow water and minerals to move most quickly through it?

• silt
• sand
• loam
• clay

Which of the following is true?

• Soil does not exist in layers
• The processes of soil formation create parent material
• the processes of soil formation create a vertical gradient of distinct soil layers
• the processes of soil formation create a random gradient of distinct soil layers

You are shown a soil profile with a very dark, humus-rich A horizon. This soil is likely from which biome?

• desert
• tropical rainforest
• temperate grassland
• tundra

What soil type is found in a classic desert or dryland?

• oxisol
• alfisol
• mollisol
• ardisol

Which soil has the finest particles?

• loam
• clay
• silt
• sand

Which of the following is true?

• As the average size of soil particles decreases, nutrient-holding capacity decreases.
• As the average size of soil particles decreases, aeration decreases.
• As the average size of soil particles decreases, workability increases.
• As the average size of soil particles decreases, water-holding capacity decreases.

Erosion usually begins when

• the topsoil is thick
• there is little or no slope to the land
• rainfall levels decrease
• the vegetation is removed 

Which of the following is the primary environmental advantage of no-till agriculture?

• migratory bird populations in the field are undisturbed
• the leftover parts of the crop reduce the O horizon
• the use of herbicides improves the overall stability of the soil
• the undisturbed soil is less susceptible to erosion

What is the impact of wind and water on bare soil called?

• salanization
• irrigation
• erosion
• mineralization

Leaching

• adds nutrients to the soil
• is caused by movement of water upward through the soil
• is a common agricultural practice that improves soil
• removes water-soluble nutrients from soil via downward movement of water