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.

Excessive use of nitrogenous fertilizers can lead to several environmental problems:

• Soil Acidity: Overuse contributes to the acidification of soil. This is because the nitrification process (conversion of ammonia to nitrate) releases hydrogen ions.

• Nitrate Leaching: Excess nitrate not taken up by plants can leach into the groundwater. This contaminates drinking water sources and can lead to health issues like methemoglobinemia (blue baby syndrome).

• Nitrogen-fixing microorganisms are generally not negatively affected by the excessive use of nitrogenous fertilizers; in fact, their activity might even be stimulated in some cases, though this is not the primary concern.

Statement 1 is incorrect. Statement 2 is correct. Statement 3 is correct. Hence, only statements 2 and 3 are correct.

Sources:

• EPA - Fertilizer and Water Quality Protection