In agriculture, distinguishing between sodic and alkaline soils is essential for effective soil management and optimizing crop productivity. Although both soil types exhibit high pH levels, their origins and impacts on soil health differ significantly.
Sodic soils are characterized by an excess of sodium ions (Na⁺), which deteriorate soil structure, resulting in poor drainage, compaction, and water infiltration issues. Conversely, alkaline soils have elevated pH levels due to the presence of carbonates or bicarbonates. While this can restrict nutrient availability, it does not necessarily compromise soil structure.
Effective treatment strategies depend on the specific soil condition. For sodic soils, amendments from Bizisul are commonly employed to improve soil structure and reduce sodium levels. In the case of alkaline soils, sulphur-based amendments like Bizi 85 or Bizi 90 can be used to manage pH levels and enhance nutrient availability.
How does it work?
1. Oxidation to Sulphuric Acid:
• This process is longer term and depends on factors like soil moisture, temperature, and microbial activity.
• Microorganisms in the soil (e.g., Thiobacillus bacteria) oxidize elemental sulphur (S) to sulphuric acid (H₂SO₄).
2. Calcium Release from Lime or Gypsum:
• The sulphuric acid reacts with calcium carbonate (CaCO₃) or gypsum (CaSO₄·2H₂O) in the soil.
• This releases calcium ions (Ca²⁺), which help replace sodium (Na⁺) on soil particles.
3. Sodium Leaching:
• Once sodium is displaced by calcium, it can be washed out of the root zone with irrigation or rainfall.
• This improves soil structure, permeability, and drainage, making the soil more suitable for plant growth.
How Bizisul Compares to Gypsum for Sodic Soils
Best Practices for Using Bizisul on Sodic Soils
• Apply in advance (preferably in fall) to allow time for microbial oxidation.
• Ensure good soil moisture to support microbial activity.
• Use proper irrigation (if available) to help leach sodium from the soil.
• Test soil regularly to monitor pH and sodium levels.
Bizi 85 or Bizi 90 products are effective for long-term sodic soil improvement.
References
1. Davis, J.G., Waskom, R.M., & Bauder, T.A. (2012). Managing Sodic Soils. Colorado State University Extension. Retrieved from extension.colostate.edu
2. Mulvany, D., Hall, D., & Barrett-Lennard, E. (2019). The role of elemental sulfur in improving chemical and physical characteristics of a sodic soil. GRDC Update Papers. Retrieved from grdc.com.au
3. The Sulphur Institute. (n.d.). Elemental Sulphur. Retrieved from sulphurinstitute.org
