Question

Given below are two statements:
Statement (I): Low salinity water can be used for irrigation with most crops and most soils. But some leaching is required.
Statement (II): Medium salinity water can be used with crops that can tolerate moderate salinity and leaching. But high salinity water is not ordinarily suitable for irrigation but to be used under special conditions with good drainage and with salt tolerant crops.
In light of the above statements, choose the most appropriate answer from the options given below:

• A. Both Statement (I) and Statement (II) are correct.
• B. Both Statement (I) and Statement (II) are incorrect.
• C. Statement (I) is correct but Statement (II) is incorrect.
• D. Statement (I) is incorrect but Statement (II) is correct.

Hint:

The US Salinity Laboratory (USSL) classifies salinity hazard into four groups:
C1: Low salinity (\( < 250\ \mu\text{S/cm} \))
C2: Medium salinity (\( 250\text{-}750\ \mu\text{S/cm} \))
C3: High salinity (\( 750\text{-}2250\ \mu\text{S/cm} \))
C4: Very High salinity (\( > 2250\ \mu\text{S/cm} \))

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Irrigation water quality is classified based on its electrical conductivity (EC), which indicates the total dissolved salt concentration.
Using highly saline water can cause salts to accumulate in the root zone, reducing crop yields and damaging the soil structure.

Step 2: Detailed Explanation:
Let us evaluate Statement (I):
Low salinity water (typically EC \( < 0.25\text{ dS/m} \)) is highly suitable for irrigation.
It can be used for almost all crops on most soils with little risk of salinity development.
However, even with low salinity water, some leaching (applying excess water to flush salts below the root zone) may be required in extremely tight, low-permeability clay soils to prevent long-term salt buildup.
Thus, Statement (I) is correct.
Let us evaluate Statement (II):
Medium salinity water (EC between \( 0.25 \) and \( 0.75\text{ dS/m} \)) can be used safely if moderate leaching is applied.
This water is suitable for moderately salt-tolerant crops.
High salinity water (EC between \( 0.75 \) and \( 2.25\text{ dS/m} \)) is generally unsuitable for irrigation under normal conditions.
It can only be used under special management conditions, which require highly permeable soils, excellent drainage systems, and the selection of highly salt-tolerant crops (like barley or cotton).
Thus, Statement (II) is correct.

Step 3: Final Answer:
Both Statement (I) and Statement (II) are correct.