•
       Crops receive moisture for their growth and development mainly from 
              Irrigation            Surface water
                                                         +           Rain water
                water               Ground water
      IRRIGATED AREA :
                    Total crop     Total crop area         Crop area under       Crop area under 
                    area (m.ha)    actually irrigated      ground water          canal irrigation 
                                   (m.ha)                  irrigation (m.ha)     (m.ha)
 India                  159.6              58.13                  39.43                22.48
 Uttar Pradesh          17.6               14.49                  10.64                4.21
 1/3rd of the cultivated area is under irrigation. In that 65 % is through ground water
   POTENTIAL :
    Surface water resources         :     1869 km3
    Catchment area of rivers        :      252.8 m.ha
    Ground water available          :      360 km3
    Ultimate irrigation potential of the country      :   139.5 mha
             Criteria for evaluation of irrigation water
             Criteria for evaluation of irrigation water
                                     Colour, odour, viscosity
              Physical properties
                                     Water temperature, density
                                       Salinity
                                       Sodium
                                       Salt index
              Chemical properties      RSC, SSP, SAR, TDS
                                            -1       -
                                       B, Cl , Mg, NO3, Li, F
                                       Heavy metals (As, Cd, Ni, Pb)
                                        OP, DO, COD, BOD
                                                 Algae
                Biological properties            Escherichia coli
                                                 Phytoplankton
          Water       Salinity      SAR          RSC          B (ppm)        Cl-1         SSP
                              -1                      -1                          -1
           class     EC (mSm )                  (me L )                    (me L )
           Low         0 – 25      0 – 10        < 1.25        < 0.33          4           15
         Medium        25 – 75     10 – 18     1.25 – 2.5       0.67         4 – 7      15 – 30
           High       75 – 225     18 – 26       > 2.5       1.00 – 1.25    7 – 12      30 – 60
        Very high     225 - 500     > 26         > 2.5         > 1.25       12 - 20       > 60
            Guidelines for irrigation water quality (FAO)
            Guidelines for irrigation water quality (FAO)
                    Component                           Intensity of problem
                                                  No         Moderate        Severe
                    EC (dSm-1)                   < 0.75      0.75 – 3.0       > 3.0
       Adj SAR (Montmorillonite domination)       < 6           6 - 9          > 9
            Adj SAR (Illite - Vermiculite)        < 8          8 - 16         > 16
         Adj SAR (Kaolinite - Sesquioxide)        < 16         16 - 24        > 24
                    Cl (me L-1)                   < 4          4 - 10         > 10
                     B (me L-1)                  < 0.75      0.75 – 2.0       > 2.0
                 NO- - N (me L-1)                 < 5          5 - 30         > 30
                     3
                   HCO- (me L-1)                 < 1.5        1.5 – 8.5       > 8.5
                       3
                        pH                      6.5 – 8.5         -         0 – 5, 9.5