The primary way to control acidity in soil is through the application of lime or other alkaline materials that neutralize the acid.
Here's a more detailed breakdown:
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Liming: This is the most common and practical technique. Limestone (calcium carbonate - CaCO3) or dolomitic limestone (calcium-magnesium carbonate - CaMg(CO3)2) is applied to the soil. The lime reacts with the acidic components in the soil, raising the pH.
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Other Alkaline Materials: Besides limestone, other materials like wood ash, basic slag (a byproduct of steel manufacturing), and marl can also be used to neutralize soil acidity.
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Factors Affecting Effectiveness:
- Product Quality: The finer the lime, the faster and more effective it will be in neutralizing acidity.
- Application Rate: The amount of lime needed depends on the soil's initial pH, its buffering capacity (resistance to pH change), and the target pH. Soil testing is crucial to determine the correct rate.
- Application Method: Thoroughly incorporating the lime into the soil is important for it to react effectively. Surface application is less effective, especially in untilled soil.
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Using Acid-Tolerant Plants: While not a method of controlling the acidity itself, planting species adapted to acidic soils allows for continued production while you implement other amelioration strategies. Examples include blueberries, azaleas, and rhododendrons.
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Managing Nitrogen Fertilizers: Ammonium-based fertilizers can contribute to soil acidity over time. Using nitrate-based fertilizers or applying nitrogen in smaller, more frequent doses can help minimize this effect.
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Organic Matter Management: Incorporating organic matter can sometimes slightly buffer against extreme acidity, although it's not a primary control method.
In summary, controlling soil acidity involves neutralizing it using alkaline materials, primarily lime. The correct application rate and method are essential for success, and acid-tolerant plants can provide temporary productivity while the soil is being amended.
