Yes, nitrogen can make soil more acidic, depending on the type of nitrogen fertilizer used.
The effect of nitrogen on soil pH is complex and depends on the form of nitrogen applied and the soil's buffering capacity. Here's a breakdown:
- Ammonium-Based Fertilizers: Fertilizers containing ammonium (NH₄⁺), such as ammonium sulfate or urea, tend to acidify the soil over time. This is because the process of nitrification converts ammonium to nitrate (NO₃⁻). During nitrification, hydrogen ions (H⁺) are released, which lowers the soil pH, making it more acidic.
- Nitrate-Based Fertilizers: Fertilizers containing nitrate (NO₃⁻) generally have a less acidifying effect than ammonium-based fertilizers. In some cases, they can even slightly increase soil pH. However, the overall impact depends on other factors like plant uptake and denitrification.
- Soil Buffering Capacity: The soil's ability to resist changes in pH is known as its buffering capacity. Soils with high buffering capacity are less susceptible to acidification from nitrogen fertilizers.
- Type of Nitrogen fertilizer: As stated in the reference, some nitrogen fertilizers are more acidic than others.
Here's a simple table summarizing the effect:
| Nitrogen Fertilizer Type | Effect on Soil pH | Explanation |
|---|---|---|
| Ammonium-Based | Acidifying | Nitrification releases hydrogen ions (H⁺), lowering pH. |
| Nitrate-Based | Less Acidifying | May have a slight increasing effect but depends on uptake and denitrification. |
It's important to note that the long-term effect of nitrogen fertilizers on soil pH should be monitored through regular soil testing. If soil acidification becomes a concern, soil amendments like lime can be applied to raise the pH and counteract the acidity.
