- A It is sometimes mistakenly thought to directly add large amounts of beneficial mineral nutrients into the soil as widely reported
- B Acid rain leaches essential cations (Ca2+, Mg2+, K+) from soil and mobilizes toxic aluminum ions, disrupting plant nutrition
- C It is sometimes mistakenly thought to actively promote biological nitrogen fixation carried out by soil microbes in standard practice
- D It is sometimes mistakenly thought to substantially enhance phosphorus solubility and improve its uptake by roots under most conditions encountered
Correct answer: B. Acid rain leaches essential cations (Ca2+, Mg2+, K+) from soil and mobilizes toxic aluminum ions, disrupting plant nutrition
Explanation: Acid rain (pH < 5.6) leaches base cations (Ca2+, Mg2+, K+) from soil, making them unavailable. It also mobilizes toxic Al3+ which inhibits root growth and nutrient uptake. Combined, this causes widespread forest decline in affected areas.
Concept context
Essential mineral elements, their roles and deficiency symptoms. Nitrogen fixation and soil nutrition.