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
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.