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