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?
[UPSC Civil Services Exam – 2011 Prelims]
(a) It greatly increases the crop production
(b) It makes some soils impermeable
(c) It raises the water table
(d) It fills the air spaces in the soil with water
Answer: (b)
Explanation:
Salinization is the presence of salts and bicarbonates in soil and water, which can lead to various problems. Here are some of them:
- Agricultural Production: Salinity can cause dehydration of plants due to inefficient osmosis, resulting in a decline in crop yield or even death of the plant. It interferes with nitrogen uptake, reduces growth, and stops plant reproduction, affecting crops, pastures, and trees.
- Water Quality: High levels of salts may affect the taste of drinking water, with chloride having a low taste threshold. Sodium and magnesium sulfate levels in drinking water may have a laxative effect and reduce its suitability for grazing animals.
- Rivers: Salt interacts with in-stream biota, changing the ecological health of streams and estuaries. Salts also help fine materials to flocculate, allowing more sunlight to penetrate rivers and leading to harmful algal blooms.
- Terrestrial Biodiversity: Salinization can destroy natural habitats in many agricultural areas and fragment wildlife corridors.
- Soil Erosion: Salinity is often associated with prolonged wetness and lack of surface cover, increasing the vulnerability of soils to erosion and making some soils impermeable.
- Flood Risk: Saline soils have a limited capacity to absorb rainfall, resulting in high rates of run-off.
- Infrastructure: Salt corrodes and destroys infrastructure, including houses, roads, and playing fields.
Therefore, option (b) is the correct answer.
