Soil Chemical Properties MCQs Quiz 2

1. At high soil pH, iron (Fe) predominantly exists in _______ form

 Soluble

 Mobile

 Insoluble

 Exchangeable

2. A decrease in soil pH from 7 to 5 indicates ______________________________

 100 times increase in acidity

 1000 times increase in acidity

 20 times increase in acidity

 2 times increase in acidity

3. ________________  is the soil type most susceptible to rapid acidification

 Calcareous soil

 Sandy soil with low organic matter

 Clay-rich soil

 Organic-rich soil

4. In calcareous soils, phosphorus (P) availability is primarily limited due to ______

 Al fixation

 Leaching

 Fe fixation

 Ca fixation

5. Active acidity in soils refers to _______

 H⁺ in the soil solution

 H⁺ adsorbed on clay surfaces

 Total soil acidity

 Al³⁺ on cation exchange sites

6. Aluminum (Al³⁺) toxicity in acidic soils primarily affects _______

 Leaf photosynthesis

 Root growth

 Flowering

 Stem elongation

7. The term “nutrient fixation” in soils refers to __________________

 Plant uptake of nutrients

 Conversion of nutrients into unavailable forms

 Loss of nutrients through volatilization

 Leaching losses of nutrients

8. Which soil component most strongly links cation exchange capacity (CEC) with soil pH?

 Gravel

 Sand

 Water

 Clay and organic matter

9. Soils with low cation exchange capacity (CEC) are most prone to _______

 High inherent fertility

 High buffering capacity

 Rapid pH changes

 Strong nutrient retention

10. Ammonia (NH₃) volatilization from soils is highest under _______

 Acidic conditions

 Neutral conditions

 Alkaline conditions

 Waterlogged conditions

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