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 nitrogenous fertilizers lead to soil acidification through the release of hydrogen ions during nitrification and cause nitrate leaching into groundwater due to the high mobility of nitrate ions. Statement 1 is incorrect because high nitrogen availability actually inhibits the activity and proliferation of nitrogen-fixing microorganisms, which are naturally more active in nitrogen-deficient conditions. The core concept tested is the environmental degradation and disruption of the nitrogen cycle caused by chemical agricultural inputs.