What can be the impact of excessive/inappropriate use of nitrogenous f

What can be the impact of excessive/inappropriate use of nitrogenous fertilizers in agriculture?

  • 1. Proliferation of nitrogen-fixing microorganisms in soil can occur.
  • 2. Increase in the acidity of soil can take place.
  • 3. Leaching of nitrate to the ground-water can occur.

Select the correct answer using the code given below.

1 and 3 only
2 only
2 and 3 only
1, 2 and 3
This question was previously asked in
UPSC IAS – 2015
Statements 2 and 3 are correct regarding the impact of excessive/inappropriate use of nitrogenous fertilizers in agriculture.
Excessive use of nitrogenous fertilizers can lead to soil degradation and environmental pollution. The process of nitrification, where ammonium from fertilizers is converted to nitrate, releases hydrogen ions, increasing soil acidity over time (Statement 2 is correct). Nitrate is highly soluble and mobile in soil, making it susceptible to leaching into groundwater, causing contamination and potential health risks (Statement 3 is correct).
Statement 1 is generally incorrect. Excessive nitrogen supply from fertilizers often suppresses the activity of symbiotic nitrogen-fixing microorganisms (like Rhizobium associated with legumes) because the plant can easily access nitrogen from the soil and reduces the need to support nitrogen fixation. Proliferation of non-fixing microbes might occur, but not specifically nitrogen-fixing ones due to direct fertilizer use.