Salinization occurs when the irrigation water accumulated in the soil evaporates, leaving behind salts and minerals. What are the effects of salinization on the irrigated land?

The correct answer is B. Salinization happens when water rises by capillary action and evaporates, leaving soluble salts in the top layer. Where sodium salts dominate, sodium ions displace calcium and magnesium on clay particles. The clay swells and disperses, forming a dense crust with very poor infiltration. That is the sense in which some soils become impermeable.

• A is wrong. High salt concentration reduces the osmotic uptake of water by roots, so yields fall. Saline land is less productive, not more.
• C is wrong. A rising water table is the cause that brings salts up through capillary rise. It is a precursor to salinization, not a direct effect of the salt left behind.
• D is wrong. Filling air spaces with water describes waterlogging. Salt deposition does not do this, although the two problems often occur together.

Concept: secondary soil degradation under canal irrigation, linked to waterlogging and drainage. For Mains GS-III, connect it to conjunctive use and the hidden costs of the Green Revolution in Punjab and Haryana.

Trap: Aspirants pick C because waterlogging and a rising water table are discussed alongside salinity. Separate the cause (waterlogging) from the salt effect (impermeability and yield loss).