Question

Leaching is a process:
1. By which alkali salts present in the soil are dissolved and drained away
2. By which alkali salts in soil come up with water
3. Of draining excess water of irrigation
4. Which controls water-logging

Answer 1

Correct Answer - Option 1 : By which alkali salts present in the soil are dissolved and drained away

Explanation:

Leaching

• It is the process of removal of alkali salts dissolved in irrigation water by flooding the land with an adequate amount of water.
• Leaching is the process of a solute becoming extracted from its carrier substance by way of a solvent. If carbon dioxide (CO2) is present in water then it enhances the leaching process.
• This is mainly done to remove the alkali salts in the top layer of land for allowing the crops to grow on the land.
• In order to reclaim land, we initially grow some salt-resistant crops on the leached land and after sometime when salinity has been reduced to the permissible extent we grow ordinary crops.

• Leaching requirement (LR) = Depth of irrigation water drained out per unit area / Depth of irrigation water applied per unit area.
• Leaching requirement is generally expressed as the percentage of total irrigation water applied to the soil to meet the consumptive use as well as the leaching needs.