What is the role of a wetting agent in irrigation management?

• A. Increases soil pH, which can improve nutrient availability.
• B. Improves water penetration in hydrophobic soils and reduces runoff.
• C. Decreases soil salinity.
• D. Increases drainage through soil profile.

Answer: (B)

Wetting agents are soil surfactants that lower water’s surface tension, helping water spread and infiltrate soils that resist wetting. In hydrophobic soils, water tends to bead up and run off, leaving the root zone dry. A wetting agent lowers these repellent forces, allowing water to enter more easily and move more uniformly through the soil, which reduces surface runoff and improves irrigation efficiency. They don’t primarily change soil pH, nor do they directly alter salinity or function as a drainage enhancer; their main role is to overcome soil water repellence and promote better infiltration and distribution of irrigation water.