9. Water Quality perameterbikkjy6ggs.ppt

Good morning sir vale kyoki

2. Quality of irrigation water

3. CONTENT
Introduction
CriteriaToDetermine
ManagementOfSalineWater

4. Introduction
Thesuitabilityofirrigationwateris
mainlydependsontheamountsandtypeof
saltspresentinwater.Themainsoluble
constituentsarecalcium,magnesium,
sodiumascationsandchloride,sulphate,
carbonate,bio-carbonateasanions.
Theotherionsarepresentinminute
quantitiesareboron,selenium,
molybdenumandfluorinewhichare
harmfultoanimalsfedonplantsgrown
withexcessconcentrationoftheseions.

5. Irrigation water quality criteria
Waterqualityisdeterminedaccordingtothe
purposeforwhichitwillbeused.Forirrigation
water,theusualcriteriaincludesalinity,sodicity,
andiontoxicities.
Variouscriteriaareconsideredinevaluatingthe
qualityofirrigationwaternamely-
Salinityhazard
Sodiumhazard
Alkalinityhazard
Saltindex
Specificiontoxicityhazards

6. SALINITY HAZARD
Theconcentrationofsolublesaltsinirrigation
watercanbeclassifiedintermsofElectrical
Conductivity(EC)andexpressedasdSm-1.
Therearefourclassesofsalinityviz.,C1,C2and
C3,C4.
TheclassesC1andC2ofwaterareconsidered
suitableforirrigationpurposes(noproblem).C3and
C4classesofwaterarenotsuitableforirrigation
purpose(severeproblems).

7. Range of salinity hazard
Water classesEC (dSm1)Remarks
C1 -Low salinity 0-0.25 Can be used safely
C2 -Medium salinity 0.25-0.75 Can be used with moderate
leaching
C3 -High salinity 0.75-2.25 Can be used for irrigation
purposes with some
management practices
C4 -Very high 2.25-5.00 Can not be used for irrigation
purposes

8. SODICITY HAZARD
Highconcentrationsofsodiumare
undesirableinwaterbecausesodiumadsorbs
ontothesoilcationexchangesites,causing
soilaggregatestobreakdownsealingthe
poresofthesoilandmakingitimpermeable
towaterflow.Thesodicityhazardof
irrigationwaterisusuallyevaluatedby
SodiumAdsorptionRatio(SAR)
AdjustedSAR
Sodiumtocalciumactivityratio(SCAR)
Sodiumratio

9. Sodium Adsorption Ratio (SAR)
UnitedStatesSalinityLaboratory(USSL)staff
introducedtheconceptofsodiumadsorptionratio
(SAR)topredictsodiumhazard.Itiscalculatedas.
Thesodiumhazardofirrigationwaterexpressed
throughSARdoesnottakeintoaccounttheeffectof
anioniccomposition.Sodicityhazardalsoclassifiedas
S1,S2,S3andS4.

10. Water classes SAR Remarks
S1 low sodium hazard 0-10 Little or no hazard
S2 medium sodium
hazard
10-18 Appreciable hazard but can be
used with appropriate
management
S3 High sodium
hazard
18-26 Unsatisfactory for most of the
crops
S4 Very high sodium
hazard
> 26 Unsatisfactory for most of the
crops
Sodium Adsorption Ratio (SAR)

11. Sodium to Calcium Activity Ratio (SCAR)
TheapplicationofSARtothegroupofwater,
whichhaveEC>5dSm-1andMg/Caratio>1is
obviouslyquestionable.Forthegroundwaterhaving
EC>5dSm-1anddominanceofmagnesiumover
calcium,theSARvalueshouldbecalculatedasNa+/
ca2+.
TheclassificationofSAR/SCARratiowasgiven
byGupta(1986)byfollowing6classesofSodicity.

12. WaterClass dSm-1
Non-sodicwater (<5)
Normalwater (5-10)
Lowsodicitywater (10-20)
Mediumsodicitywater (20-30)
Highsodicitywater (30-40)
Veryhighsodicitywater (>40)

13. Alkalinity hazard
ResidualSodiumCarbonate(RSC)
ResidualSodiumBicarbonate(RSBC)
Bicarbonates(HCO3-)occurinlowsalinitywater
anditsconcentrationusuallydecreaseswithan
increaseinEC.
Theproportionofbicarbonateionishigherthan
calciumionsareconsideredundesirable,because
afterevaporationofirrigationwaterbicarbonateions
tendtoprecipitatecalciumions.Hence,theeffectof
bicarbonatetogetherwithcarbonatesevaluated
throughRSC.
RSC=(CO3¯+HCO3¯)-(Ca2++Mg2+),allions
expressedasmeL-1.

14. RSC (mel-1) Water quality
< 1.25 Water can be used safely
1.25 -2.5 Water can be used with certain management
> 2.5 Unsuitable for irrigation purposes
Residual Sodium Carbonate (RSC)

15. Sincecarbonateionsdonotoccurveryfrequently
inappreciableconcentrations,andasbicarbonate
ionsdonotprecipitatemagnesiumions,Gupta
suggestedthatalkalinityhazardshouldbe
determinedthroughtheindexcalledResidual
SodiumBicarbonate(RSBC)tobecalculatedas
below.
RSBC=HCO3--Ca2+,allionsexpressedasme
L-1.BasedonRSC/RSBCratio.

16. Salt tolerant varieties of different crops
Crops Varieties
Paddy CSR-10 , CSR-11, JAYA, SAKET-1
Wheat Raj-3077, WH-157, HD-2009, HD-2329, C-306
Mustard Pusabold, Varuna, Vardan, rohini, NRCBH-506
Sugarcane Co-453, Co-1341,Co-6801 , Co-1111
Groundnut K-3, HNG-10, HNG-123
Cotton H-777, Bikanerinarma, AK-235, Sangam

17. SPECIFICION TOXICITY HAZARD
Sodium:Amongthesolubleconstituentsof
irrigationwater,sodiumisconsideredmost
hazardous.Excessofsodiumionscharacterizesthe
waterassalineoralkalinedependinguponits
occurrenceinassociationwithchloride/sulphateor
carbonate/bicarbonateions.Forsometimeinthe
past,thequalityofirrigationwaterusedtobe
evaluatedwithrespecttosodiumbasedonsoluble
sodiumpercentage(SSP)calculatedasbelow.

18. Salt index-It is also used for predicting sodium
hazards. It is the relation between Na*, Ca*2,
CaCO3 present in irrigation water.
Salt Index = (Total Na -24.5) –(Total Ca-Ca in CaCO3) x4.85

19. Magnesium:Itisbelievedthatoneofthe
importantqualitativecriteriainjudgingthe
irrigationwaterisitsMgcontentinrelationtototal
divalentcations,sincehighMgcontentinrelation
tototaldivalentcations,sincehighMgadsorption
bysoilsaffectstheirphysicalproperties.Aharmful
effectonsoilsappearswhenCa:Mgratiodecline
below50.

20. Chlorides:Theoccurrenceofchlorideionsin
irrigationwaterincreaseswithincreaseinECand
sodiumions.Therefore,theseionsaremost
dominantinveryhighsalinitywater.Unlikesodium
ions,thechlorideionsneitheraffectonthephysical
propertiesofthesoil,norareadsorbedbythesoil.
Therefore,ithasgenerallynotbeenincludedin
modernclassificationsystem.However,itisusedasa
factorinsomeregionalwaterclassification.

21. Chloride concentration
Chloride concentration
(meL1)
Water quality
4 Excellent water
4-7 Good water
7-12 Slightly usable
12-20 Not suitable
> 20 Not suitable

22. Chloride tolerance of different crops
Crops Threshold
Cl-Cone (Me/l)
Bean, Onion,Radish, 10
Potato, Cabbage , Maize, Sugarcane 15
Sudan grass , Paddy 30
Wheat 55
Sorghum , Sugarbeat 70
Cotton 75
Barley 80

23. Sulphate:Sulphatesaltsarelessharmfulwhen
comparedtochlorides.Thisisbecausewhenboth
theionsoccurinthisconcentration,onlyhalfofthe
sulphateionscontributetosalinityduetothefact
thatapproximatelyhalfofthesulphatesgets
precipitatedasCaSO4whiletheotherhalfremains
insolubleformasNa-MgSO4inthesoil.Thatisthe
reason,thepotentialsalinityofirrigationis
calculatedasCl-+⅟₂SO4-.Eatonproposedthree
classesforsulphate.
 <4mel-1-Excellentwater
 4-12mel-1-Goodtoinjurious
 >12mel-1-Injurioustounsatisfactory

24. Potentialsalinity
ItcanbeworkedoutbyusingtheformulaCl+1/2
SO42-whereionsareexpressedinmel-1.
Potential salinity
(me L-1)
Remarks
3-15 Can be recommended for medium
permeability
soils
3-7 Recommended for soils of low
permeability

25. Boron:Itisevidentthatboronisessentialforthe
normalgrowthoftheplant,buttheamountrequired
isverysmall.Theoccurrenceofboronintoxic
concentrationincertainirrigationwatermakesit
necessarytoconsiderthiselementinassessingthe
waterquality.Thepermissiblelimitsofboonin
irrigationwaterare.

26. Boron Concentration
Class Sensitive Semi sensitiveTolerant Remark
Very low <0.33 <0.67 <1.0 For safety use
Low 0.33-0.67 0.67-1.33 1.0-2.0 Can be
management
Medium 0.67-1.0 1.33-2.00 2.0-3.0 Unsuitable
Very High >1.25 >2.50 >3.67 Unsuitable

27. Boron tolerant limits for agriculture crops
Crop Thresholdppm
Sensitive
Grape fruits 0.5-0.75
Moderately tolerant
Pea 1.0-2.0
Cauliflowers 2.0-4.0
Tolerant
Sugar beet 4.9
alfalfa 4.0-6.0
Tomato 5.7
Very tolerant
Sorghum 7.4
Cotton 6.0-10.0

28. Nitrate:Veryfrequentlygroundwatercontain
highamountofnitrate.Whensuchtypeof
irrigationwaterisappliedonsoilscontinuously,
variouspropertiesofsoilsareaffected.
NO3 mel-1 Remark
< 5 No problem
5-30 Intensity of problem is moderate
> 30 Intensity of problem is severe

29. Fluorine:Fluoridesareonlysparinglysolubleand
areinonlysmallamounts.Theconcentrationof
fluoriderangesfromtracestomorethan10mgL-1
innaturalwater,andsurfacewaterdonotexceed0.3
mgL-1unlesstheyarepolluted.Irrigationwith
fluoridesalinewater(upto25mgL-1)hasnotbeen
foundtoaffectyieldofwheat.Therefore,itisdoubtful
iffluoriderequiresanymonitoringinIndia.At
present,theaverageconcentrationoffluoridehasnot
beenobservedtobeveryhigh(10mgl-1).

30. Lithium:Lithiumisatraceelementmaybe
foundinmostofsalinegroundwaterandirrigated
soils.Ithasbeenfoundthat0.05-0.1ppmoflithium
inwaterproducetoxiceffectsongrowthofcitrus.
Ithasalsobeenreportedthatsalinesoilsof
varyingdegreesfoundinIndiacontainlithiumupto
2.5ppm.Fortunately,thegerminationofmajorityof
cropsisnotaffectedwiththisleveloflithium
content.

31. Guidelines for irrigation water quality established (FAO)
Water Constituent No problem Moderate Severe
Salinity (dsm-1)
Permeability <0.70 0.70-3.00 >3.0
Salinity <0.5 0.5-2.00 >2.0
Adj., SAR
Dominantly Montmorllonite <6 6-9 >9
Dominantly illite, Vermiculite<8 8-16 >16
Dominantly Kaolinit <16 16-24 >24
Specific ion toxicity
Sodium (adj. SAR) <3 3-9 >9
Cl-( mmolL-1) <3 >3 >10
Boron(mmolL-1) <0.70 0.70-3.0 >3.0
Miscellaneous
No3-N or NH4*-N( mmolL-1)<5 5-30 >30
HCo3( mmolL-1) <1.5 1.5-8.5 >8.5
pH 6.5-8.5 >9.5

32. MANAGEMENT PRACTICES FORUSING
POORQUALITYWATER
Applicationofgypsum
Alternateirrigationstrategy
Fertilizerapplication
Methodsofirrigation
Croptolerance
Methodofsowing
Drainage

33. Other management practices
Overagedseedlingsinrice
Mulching
Soilmanagement
Croprotation:
Salinity control with slopingbeds

34. CropTolerance
Thecropsdifferintheirtolerancetopoorquality
waters.Growingtolerantcropswhenpoorquality
waterisusedforirrigationhelpstoobtain
reasonablecropsyields.Relativesalttoleranceof
cropsisgiveninTable

35. CropTolerance:
Tolerant
Field crops: Cotton, Safflower, Sugarbeet& Barley
Fruit crops: Date palm & Guava
Vegetables: Turnip & Spinach
Forage crops: Berseem& Rhodes grass
Semi
tolerant
Field
crops: Sorghum, Maize, Sunflower,
Bajra, M
Wheat
Fruit crops: Fig, Grape & Mango
Vegetbles: Tomato, Cabbage, Cauliflower,
a CucuPotato Forag
e crops: Senji& Oats
ustard, Rice
&
mber, Carrot
&
Sensitive
Field crops: Chick pea, Linseed, Beans, Greengram&
Blackgram
Fruit c rops: Apple, Orange, Almond, Peach, Strawberry,
Lemon &
Plum
Vegetables: Radish, Peas & Lady’s finger