1. Slower Reaction and Controlled pH Change: Powdered limestone has a slower reaction rate than calcium hydroxide. It gradually dissolves and releases calcium ions over time, allowing the soil pH to rise slowly and steadily. This reduces the risk of overliming, which can occur when the pH increases too rapidly, potentially causing nutrient deficiencies and plant damage.
2. Reduced Alkalinity: Powdered limestone has a lower alkalinity than calcium hydroxide. While calcium hydroxide is highly alkaline and can raise the soil pH significantly, powdered limestone provides a more moderate increase in alkalinity. This helps to prevent excessive alkalinity and potential nutrient imbalances in the soil.
3. Improved Soil Structure: Powdered limestone can improve the soil structure by providing a source of calcium ions, which help to flocculate clay particles and improve soil aggregation. This leads to better aeration, drainage, and water infiltration, promoting root development and overall soil health.
4. Reduced Leaching: Calcium ions from powdered limestone are less prone to leaching than other forms of lime, such as calcium hydroxide. Leaching is the process of nutrients being lost from the soil profile due to excessive rainfall or irrigation. The slow release of calcium ions from powdered limestone helps to maintain the soil pH and prevent nutrient deficiencies caused by leaching.
5. Environmental Considerations: Powdered limestone is a natural material and has a lower carbon footprint compared to calcium hydroxide. Calcium hydroxide production requires high temperatures and energy input, contributing to greenhouse gas emissions. Powdered limestone is a more environmentally friendly alternative, as it is extracted and processed with minimal energy requirements.
Overall, using powdered limestone is considered safer and more sustainable compared to calcium hydroxide for neutralising acidic soil. Its slower reaction rate, reduced alkalinity, soil structure improvement, reduced leaching, and environmental benefits make it a preferred choice in agricultural and landscaping practices.
