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Irrigation water having the concentration of Na++, Ca++ and Mg++ as 20, 3 and 1 Milli equivalent per litre respectively will be classified as

A. Low sodium water

B. Medium sodium water

C. High sodium water

D. Very high sodium water

Answer: Option D

Solution(By Examveda Team)

Irrigation water is classified based on its sodium concentration relative to the concentrations of calcium and magnesium ions. The classification is determined by the sodium absorption ratio (SAR), which is calculated using the following formula:

SAR = (Na++ / √(Ca++ + Mg++)) * 100

Given the concentrations provided:

Na++ = 20 meq/L
Ca++ = 3 meq/L
Mg++ = 1 meq/L


Plugging these values into the SAR formula:
SAR = (20 / √(3 + 1)) * 100
SAR ≈ (20 / √4) * 100
SAR ≈ (20 / 2) * 100
SAR ≈ 10 * 100
SAR ≈ 1000

According to the classification:

SAR < 10: Low sodium water
10 ≤ SAR < 18: Medium sodium water
18 ≤ SAR < 26: High sodium water
SAR ≥ 26: Very high sodium water

Since the calculated SAR is approximately 100, the irrigation water falls into the category of very high sodium water.

This Question Belongs to Civil Engineering >> Irrigation Engineering

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Comments ( 8 )

  1. Bipin Bhatt
    Bipin Bhatt :
    4 days ago

    How

  2. Devendra Ameta
    Devendra Ameta :
    3 years ago

    SAR= Na+/Root of (Mg+2)+(Ca+2)/2 so
    SAR=20/Root of 1+3/2
    =20/Root2
    =10×Root 2
    =14.14 Which is in Medium Sodium Water

  3. Junaid Nisar
    Junaid Nisar :
    3 years ago

    Correct answer is 14.14
    So acc. to SAR value 10-18 value comes under medium sodium water

  4. Subham Raj
    Subham Raj :
    3 years ago

    1_10. Tk low sodium water
    10-18tk medium sodium water
    18-26high sodium water
    26< very high

  5. Nekibuddin Ahmed
    Nekibuddin Ahmed :
    3 years ago

    SAR=Na++upon((ca++)+(Na++)/2) whole to the power half=14.14 so anwser b is correct
    0

  6. Vishal Shakya
    Vishal Shakya :
    4 years ago

    20/√((3+1)/2)
    =14

  7. Vishal Shakya
    Vishal Shakya :
    4 years ago

    The given ans is wrong plz check it will be 2304
    Sol. 7% per 300m
    For 1200m -28%will be increase
    So 1.28*1800=2304m

  8. CHANAK GP
    CHANAK GP :
    4 years ago

    1-10 = low sodium water
    10-18 = medium sodium water
    18-26 = high sodium water
    >26 = very high sodium water

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