Correct Option
The correct option is 1, 2 and 3 only.
Explanation
The Indira Gandhi Canal, previously known as the Rajasthan Canal, is one of the largest canal systems in India. Designed to transform the arid Thar Desert into agriculturally viable land, its introduction has had significant positive and negative ecological consequences on the region's land resources.
Statement-wise Analysis
- Statement 1 is Correct: The introduction of canal irrigation significantly increased the availability of soil moisture in the arid region. This transformation allowed for the cultivation of crops and the growth of natural vegetation, effectively greening parts of the desert that were previously barren.
- Statement 2 is Correct: To protect the canal and agricultural lands from shifting sands, extensive afforestation and pasture development programmes were implemented. These measures successfully stabilized sand dunes and reduced their mobility by acting as windbreaks and binding the soil.
- Statement 3 is Correct: Despite the benefits, the intensive use of irrigation water has led to severe ecological degradation. In many areas, the excessive application of water, combined with poor drainage and the presence of a hard gypsum layer beneath the soil, has caused the water table to rise. This has resulted in widespread waterlogging and secondary soil salinity.
- Statement 4 is Incorrect: The canal system has not eliminated the risk of soil salinity; rather, it has exacerbated it in specific zones due to waterlogging and capillary action, which brings salts to the surface. Soil salinity remains a critical challenge in the Canal Command Area.
Key Takeaway
Key Takeaway: While canal irrigation in arid regions enhances soil moisture and vegetation cover, unsustainable irrigation practices and poor drainage often lead to land degradation issues such as waterlogging and soil salinization.