PLS 2- Chapter #11- Soil Organisms

What is humus composed of?

• Only water and air

• Only sand and clay

• Only dead leaves and roots

• Bits of dead, rotting insects, animals, leaves, roots, sticks, and food

Which soil type holds water and feels slippery when wet?

• Gravel

• Clay

• Sand

• Silt

What is the size range of sand particles?

• 0.004 to 0.006 millimeters

• 0.006 to 2.00 millimeters

• 2.00 to 4.00 millimeters

• 0.004 to 0.004 millimeters

Which organism releases excess nitrogen that is beneficial for plants?

• Nematodes

• Protozoa

• Fungi

• Arthropods

What is the role of earthworms in the soil?

• They attack crop roots and cause diseases

• They release nutrients by eating bacteria

• They create tunnels to help water move and provide pathways for plant roots

• They only decompose dead organic matter

Which fungi is known to attack sugar beets?

• Cercospora Beticola

• Aspergillus niger

• Laetisaria arvalis

• Penicillium

What is the estimated percentage of methane released to the atmosphere that passes through the soil each year?

• 90%

• 30%

• 70%

• 50%

What is the main benefit of modern farming practices like no-till farming?

• They reduce the need for fertilizers

• They increase the number of bad fungi

• They minimize soil disturbance and return plant residues to the soil

• They increase the amount of clay in the soil

What is the main function of arthropods in the soil?

• They release excess nitrogen

• They create tunnels for water movement

• They only decompose dead organic matter

• They prey on disease-causing pests and help shape soil structure

What is the main reason soil is considered our greatest resource?

• It does not require any maintenance

• It is abundant and easy to replace

• It supports plant growth, cleans water, and provides a base for buildings

• It is not affected by erosion or contamination