• Potassium Chloride (KCl, MOP) and Ammonium Nitrate have high salt indices.
• Monoammonium Phosphate (MAP) and Urea have moderate to low salt indices.

• Osmotic Stress (Primary Effect): High salt concentration in the soil solution makes it harder for plant roots to take up water (physiological drought). This reduces growth and yield, regardless of nutrient availability.
• Specific Ion Toxicity:

Chloride (Cl⁻) and Sodium (Na⁺): Can accumulate to toxic levels from fertilizers (e.g., KCl) or irrigation water, causing leaf burn and necrosis.

Boron (B): While an essential micronutrient, it becomes toxic at slightly elevated concentrations, often from fertilizer blends or water.

• Nutrient Imbalance & Antagonism
  • High concentrations of one ion can interfere with the uptake of another.
  • High Na⁺ can depress Ca²⁺ and K⁺ uptake.
  • High Cl⁻ can reduce nitrate (NO₃⁻) uptake

This leads to deficiencies even when the nutrient is present in the soil.

• Reduced Fertilizer Efficiency: Plants under salt stress have reduced metabolic activity and root function, making them less able to absorb and utilize applied nutrients.

• Choose fertilizers with a low salt index for sensitive crops or pre-plant applications.
• Use nitrate-based nitrogen (e.g., Calcium Nitrate, Potassium Nitrate) instead of chloride- or ammonium- based sources where Cl⁻ or NH₄⁺ toxicity is a concern.
• Avoid KCl if possible; use Potassium Sulfate (K₂SO₄) or Potassium Nitrate (KNO₃) as alternative K sources.
• Use fully acidulated phosphate fertilizers (e.g., TSP, MAP) rather than partially acidulated ones in high- pH, calcareous saline soils.

• Split Applications: Apply fertilizers in several smaller doses throughout the season rather than one large dose to avoid sharp increases in soil EC.
• Localized Placement (Banding): Place fertilizer away from seeds to prevent salt injury during germination. Side-  band rather than seed-place
• Fertigation via Drip Irrigation: This is the most effective method for saline conditions. It allows for continuous, low- concentration feeding and helps leach salts away from the active root zone (the "bulb" of wet soil).
• Injection Strategy: Start irrigation with clean water first, inject fertilizer in the middle of the irrigation cycle, and finish with clean water to flush salts from the system and the root zone.

• Adequate Leaching: The only way to remove salts is by applying excess water (beyond crop needs) to leach them below the root zone. This requires calculating and applying a Leaching Fraction (LF).
• High-Frequency Irrigation: Maintaining consistently high soil moisture through frequent irrigation (especially with drip systems) dilutes the salt concentration in the soil solution, reducing osmotic stress.
• Water Quality: Always consider the salinity (EC) and ion composition of the irrigation water when calculating total salt input and designing a fertilization program.

• Soil Amendments: Gypsum (CaSO4) can be applied to sodic-saline soils (high Na⁺) to improve soil structure and facilitate leaching.
• Crop Selection: Grow more salt-tolerant crops (e.g., barley, cotton, sugar beet, some forage grasses) in problem areas.
• Organic Matter: Adding compost or manure improves soil structure, water holding capacity, and microbial activity, which can help buffer salinity effects.

• Soil: Regular monitoring of soil EC (saturated paste extract or 1:2 soil:water method) and specific ion concentrations (Na⁺, Cl⁻).
• Water: Frequent testing of irrigation water EC and composition.
• Plant: Visual symptom scouting and, if possible, periodic plant tissue analysis to detect toxicities or imbalances.