Management of Salt-Affected Soils
A. Management of Saline Soils
a. Mechanical Methods
- Leaching: Flooding fields to wash salts below the root zone.
- Surface Scraping: Removing salt deposits (temporary solution).
b. Cultural Methods
- Drainage: Installing artificial or underground drains.
- Use of salt-free irrigation water: Prevents further salinity buildup.
- Proper irrigation: Maintaining soil moisture at field capacity.
- Planting in furrows: Avoids high salt concentration on ridges.
- Ploughing & leveling: Improves infiltration and leaching.
- Reducing evaporation: Using mulch and light frequent irrigation.
- Acidic fertilizers (e.g., ammonium sulfate): Lowers pH.
- Organic manure: Increases water-holding capacity and reduces salt stress.
- Growing salt-tolerant crops:
- High tolerance: Barley, sugar beet, sorghum, cotton.
- Moderate tolerance: Wheat, maize.
- Low tolerance: Beans, radish.
- Sensitive crops: Tomato, potato.
B. Management of Sodic & Saline-Sodic Soils
a. Chemical Methods
Gypsum (CaSO₄·2H₂O):
- Replaces Na⁺ with Ca²⁺, improving soil structure.
- Requires leaching to remove Na₂SO₄.
Gypsum requirement formula:
Gypsum (meq/100g soil) = (ESP initial − ESP desired) 100 × CEC
ESP initial−ESP desired
Elemental Sulfur (S) & Sulfuric Acid (H₂SO₄):
- Converts Na₂CO₃ into Na₂SO₄, which is leachable.
- Encourages microbial oxidation and acidification.
Organic Matter Addition:
- Enhances microbial activity, increases acidity, and improves soil aggregation.
Molasses Application:
- Provides energy for microbes, enhancing organic acid production and reducing pH.
b. Cultural Methods
- Same as saline soil management.
Conclusion
- Saline soils require leaching and proper irrigation to remove salts.
- Sodic soils need gypsum, sulfur, and organic amendments to replace Na⁺ and improve soil structure.
- Salt-tolerant crops can be grown in affected areas to maintain productivity.