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
% of wells with greater than 10 ppm nitrates
0
5
10
15
20
25
30
Sand Loam ClayLoam
Clay
Calculated Regional N Balance - OECD
Country Nitrogen Balancekg N/ha/yr
PercentChange
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
Source: Environmental Sustainability of Canadian Agriculture
69% of Ont farmland increased at least 5kg/ha between 1981 and 1996
% Ont Farmland
26%
22%
15%
37%
21 - 40
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
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
Measured Ontario Soil nitrate-N (kg/ha)
2001-2003
NO3+NH4 (kg ha-1)
0.00
50.00
100.00
150.00
200.00
0 20 40 60
Kg
N/h
aResidual soil N, Hort sites, Nov 2002
Co-operator
60kg/ha A soil
80kg/ha B soil
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
0
10
20
30
40
soil
nitr
ate
ppm
Sep
-03
Oct
-03
Nov
-03
0-30
cmA
pr-0
4
30-6
0cm
Apr
-04
Bare soil
Oats
Peas
Oilseed radish
Wheat
Soil Nitrate Levels under Cover Crops (planted Aug.15, 2003 after cucumbers)
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
y = -7E-05x2 + 0.0123x + 6.314
R2 = 0.1404
4.0
5.0
6.0
7.0
8.0
9.0
0 50 100 150 200
Nitrogen Fertilizer (lbs/ac)
Yie
ld (
ton
s/a
c)
Total Yield(avg tons/ac)
Marketable Yield(avg tons/ac)
2003 Perth Yield Response to Nitrogen
y = -0.0004x2 + 0.0772x + 3.6079
R2 = 0.70484.0
5.0
6.0
7.0
8.0
9.0
20 70 120 170
Nitrogen Fertilizer (lbs/ac)
Yie
ld (
ton
s/a
c)
Total Yield(avg tons/ac)
Poly. (Total Yield(avg tons/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