Fundamentals of Plant Nutrition MCQs Quiz 17

1. Biological nitrogen fixation in leguminous plants is primarily carried out by _______

 Blue-green algae

 Rhizobium

 All of these

 Fungi

2. Decomposition of organic matter is mainly carried out by _______

 Aerobic microbes

 Protozoa

 Fungi only

 Anaerobic microbes

3. High soil salinity affects nutrient uptake by ________________________

 Causing ionic imbalance

 Increasing diffusion

 Reducing precipitation

 Enhancing mineralization

4. Nutrient uptake by plant roots occurs through _______

 None of these

 Passive transport

 Active transport

 Both active and passive transport

5. High soil organic matter improves buffering capacity due to _______

 Low surface area

 High bulk density

 Low microbial activity

 High reactivity

6. Nitrification is the process of _______

 Conversion of nitrate to nitrogen gas

 Oxidation of ammonium to nitrate

 Incorporation of nitrogen into organic matter

 Reduction of nitrate to ammonium

7. Urea contains approximately _______ nitrogen

 46%

 18%

 21%

 30%

8. Root interception contributes to nutrient uptake by _______

 Transport via water

 Gas exchange

 Microbial breakdown

 Direct root contact with nutrients

9. A __________________________ is the factor that most strongly increases microbial nitrogen (N) demand in the soil

 Low carbon availability

 Low temperature

 High substrate C:N ratio (carbon-to-nitrogen ratio)

 Low substrate C:N ratio (carbon-to-nitrogen ratio)

 High soil aeration

10. Soil moisture influences nutrient availability primarily by affecting _______

 Nutrient mobility

 Bulk density

 Soil texture

 Soil color

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Fundamentals of Plant Nutrition MCQs Quiz 17