Soil

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

• silt
• sand
• loam
• clay

Overirrigation in dry areas can cause

• plant growth that suffers as a result of high relative humidity
• a minor problem that affects only a small area
• the formation of gullies
• none of the above

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

Which of the following will reduce erosion

• cultivating the land straight up and down a slope
• tilling fields often
• traditional plowing with heavy machinery
• planting trees between fields

Which of the following leads to the greatest amount of soil erosion? 

• irrigation
• organic fertilizers
• clear-cutting trees from hillsides
• no-till agriculture

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