Nitrogen and Groundwater

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					OMAF Nitrogen Verification
        Project
      Crop Technology Team


    200 sites across Ontario (70 Hort)
      3 years - 4 samples per year
            2,400 soil samples!
      Nitrogen and Groundwater

•   23% of Ontario residents rely on groundwater
•   90% of rural residents
•   15% of rural wells above 10 ppm NO3-N
•   nitrates are the main quality issue
•   soils with high leaching potential are at most
    risk
         1992 Groundwater Survey -
                 Nitrates
                  1296 Rural Wells
             30
             25
% of wells
with greater 20
than 10 ppm 15
nitrates
             10
              5
              0
                  Sand   Loam   Clay   Clay
                                Loam
Calculated Regional N Balance - OECD
        Country       Nitrogen Balance Percent
                          kg N/ha/yr   Change
                      1985-87   1995-97
          Canada        6         13      113
         Denmark       154       119      -23
           France       59        53      -11
           Japan       145       135      -7
      New Zealand       5         6       32
      United States     25        31      24

MacDonald, 2000
                          Calculated N Balance - 1996


69% of Ont farmland increased
at least 5kg/ha between 1981 and 1996




                                                                           % Ont
                                                                          Farmland
                                                                            26%
                                                                21 - 40     22%
                                                                            15%
                                                                            37%


 Source: Environmental Sustainability of Canadian Agriculture
           Risk Assessment
• Residual N isn’t necessarily the most
  accurate measure of risk on a farm-by farm
  basis
• Non- Farmers will use this data, unless
  given something better
Measured Ontario Soil nitrate-N (kg/ha)
            2001-2003
                         All    Field    Hort
     Max   Thaw     192        140      192
           Harvest 280         280      216
           Freeze   188        188      160


     Median Thaw    44         46       38
           Harvest 56          56       58
           Freeze   43         44       41
Measured Ontario Soil nitrate-N (kg/ha)
            2001-2003
                     Coarse   Medium        Fine
      Max   Thaw     124      192      108
            Harvest 232       248      280
            Freeze   164      188      168


      Median Thaw    32       48       52
            Harvest 44        60       64
            Freeze   36       44       48
Residual soil N, Hort sites, Nov 2002

                       NO3+NH4 (kg ha-1)

          200.00

          150.00
Kg N/ha




          100.00
                                                80kg/ha B soil
                                                60kg/ha A soil
           50.00

            0.00
                   0        20             40    60

                                 Co-operator
                 Next Steps
• Add 2004 data
• Add Survey information to the database
• Separate out specific production systems
  – identify efficiencies and “leaks”
• Target management systems to reduce risks
          Related Projects
• Cover Crops/Catch Crops
Soil Nitrate Levels under Cover Crops
            (planted Aug.15, 2003 after cucumbers)


                     40
                                                                        Bare soil
  soil nitrate ppm




                     30                                                 Oats
                     20                                                 Peas
                                                                        Oilseed radish
                     10
                                                                        Wheat
                      0
                                            Nov-03
                          Sep-03


                                   Oct-03




                                                     0-30cm


                                                              30-60cm
                                                     Apr-04


                                                               Apr-04
           Related Projects
• Cover Crops/Catch Crops
• Sweet Corn Nitrogen on-Farm
  Demonstration Trials
• 40 Years of Field Corn Nitrogen Database
                            2004 Elgin 6 - Yield Response to Nitrogen

                  9.0

                  8.0
Yield (tons/ac)




                                                                              Total Yield
                  7.0                                                         (avg tons/ac)
                  6.0                                                         Marketable Yield
                                                   2
                                        y = -7E-05x + 0.0123x + 6.314         (avg tons/ac)
                  5.0
                                                 R2 = 0.1404
                  4.0
                        0       50          100           150           200
                                 Nitrogen Fertilizer (lbs/ac)
                             2003 Perth Yield Response to Nitrogen

                  9.0

                  8.0
Yield (tons/ac)




                                                                           Total Yield
                  7.0                                                      (avg tons/ac)
                  6.0                                                      Poly. (Total Yield
                                                                           (avg tons/ac))
                  5.0             y = -0.0004x2 + 0.0772x + 3.6079
                                            R2 = 0.7048
                  4.0
                        20         70              120               170
                               Nitrogen Fertilizer (lbs/ac)
             Related Projects
• Cover Crops/Catch Crops
• Sweet Corn Nitrogen on-Farm Demonstration
  Trials
• 40 Years of Field Corn Nitrogen Database
• Fertigation Scheduling in Melons & S.berries
  – Tissue/Petiole Rec’s vs. Weekly Program

				
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