REDUCING NUTRIENT LOADS IN  AGRICULTURAL LAND DRAINAGE SYSTEMS

Keynote Presentation to10th

International Drainage Workshop

July 08, 2008Helsinki, Finland

ByChandra A. Madramootoo

McGill University, Montreal, Canadaand

Vice President Hon. ICID

Spring field conditions

Subsurface pipe drainage installation

Montreal Gazette June 2008

Montreal Gazette June 2008

Water quality impacts

DRAINAGE FOR:

•Crop production?•Water quality improvement?•Flood control?

Making best use of outlets

Drain outlets

Pumped outlet

Gravity outletGravity outlet

Surface inlet

Nitrogen Cycle

McGill Water Management  Research Facility

St. Emmanuel, Qc

75 m

30 m15

m

N

Buildings

FDSIBuffer FDBuffer SI

Block C Block B Block A

Surface runoff plots

McGill Water Management Research Facility

St. Emmanuel, Qc

Field Layout

NO3-N Concentrations in mg/L

1998 1999FD SI FD SI

Jun 5.2 1.03 2.5 2.0Jul 5.1 1.5 2.5 1.5Aug 3.7 1.02 2.5 1.5Sep 2.7 0.7 2.5 1.5Oct 3.0 1.0 4.5 2.0Nov 3.2 1.0 4.5 2.0

Sample date

Denitrification rate (g N ha-1 day-1)†1996 1997

FD SI FD SI11 July15 July23 July6 Aug18 Aug22 Aug3 Sept.17 Sept.20 Sept.3 Oct.5 Oct.

—185—

31.3—

27.35.5—

14.3—

4.64

—225—

113*—

21.830.5*

—25.8—

15.3*

36.1—6.76.81.1—4.87.8—4.9—

38.1—

14.2*7.2

8.78*—

12.0*20.0*

—11.2*

—

Yield Increases due to Subirrigation McGill Water Management Research

Facility St. Emmanuel, QC

Treatment Grain corn yield (t/ha)2001 2002

Subirrigation 9.4 10.1

Non-irrigated 6.9 7.6

% increase 36% 33%

Site Locations

Missisquoi Bay

Pike River

3

4

21

H flume for surface runoff

Flow meter and sampler for Subsurface drainage

Instrument Shelter

Site DescriptionField Area Soil Type1 7 ha Sandy Clay Loam2 6 ha Sandy Loam3 2 ha Clay Loam4 3 ha Sandy Clay Loam

Field Drainage Crops1 Surface + Tile Corn, Soybeans2 Surface + Tile Alfalfa, Corn3 Only Surface Corn, Cereals4 Only Surface Hay, Pasture

Site Description

Field Soil Test P (kg/ha)

% P sat

1 114 5.3

2 373 22.0

3 38 1.6

4 72 4.0

Understanding the field hydrologic and water quality processes –

Measurements and modelling

1000 mm

100 mm

400 mm

450 mm

TILE DRAINAGE

Spring Season Hydrology

Importance of the seasonEnvironmentally sensitive Snowmelt High Intensity stormsFertilizer ApplicationsHigh Runoff RatioHigh Erosion Potential

Field hydrology (% of total rain)Runoff (10% - 25% dry - wet)Tile drainage (55% - 66% dry - wet)

Year Field Rain SS SRO %SS %SRO

mm mm mm

2002 1 342.1 229 61.4 66.9% 17.9%

2 376.3 277.5 31.8 73.7% 8.5%

2003 1 232.3 134.4 22 57.9% 9.5%

2 257.8 190 12.8 73.7% 5.0%

2004 1 240.5 123.8 n/a 51.5% n/a

2 244.3 181.8 n/a 74.4% n/a

2006 1 368.4 243.9 90.1 66.2% 24.5%

2 364.2 206.2 38.6 56.6% 10.6%

3 346.5 - 51.3 - 14.8%

Seasonal Phosphorus Loads

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

Measured Simulated Measured Simulated Measured Simulated Measured Simulated

Site #1 Site #2 Site #1 Site #2

Particulate P Dissolved P

Site | Season

Load

(kg/

ha)

Spring Summer Fall Winter

Particulate P is the main form of phosphorus exiting the fieldP in surface runoff (60%) and subsurface flow (40%)Mean concentrations consistently exceed MENV guidelines of 0.03 mg/l

0

100

200

300

400

500

600

0 20 40 60 80 100Drain spacing (m)

Flow

(mm

)

0

25

50

75

100

Tile

dra

inag

e/ T

otal

flow

) %

.

SubsurfaceSurface

%

0

100

200

300

400

500

600

0 20 40 60 80 100Drain spacing (m)

Flow

(mm

)

.

0

25

50

75

100

(Tile

dra

inag

e/To

tal F

low

) %

.

Subsurface

Surface

%

Site B Site A

DRAINMOD Simulated Surface Runoff and  Tile Flows for Different Drain Spacings

Sandy clay loamSandy loam

0

0,3

0,6

0,9

1,2

1,5

1,8

0 0,3 0,6 0,9 1,2 1,5 1,8Log (Tile drainage depth (mm) + 1)

Log

( TP

(g/h

a) +

1)

.

0

0,5

1

1,5

2

2,5

0 20 40 60 80 100Drain spacing (m)

P lo

ads

(kg/

ha/y

r)

TP

TPP

TDP

0

0,2

0,4

0,6

0 20 40 60 80 100Drain spacing (m)

Plo

ads

(kg/

ha/y

r)

TDP

TP

TPP

(a) Site 1 (b) Site 2

Simulated P Concentrations in Tile Flow for  Different Drain Spacings

Sandy clay loam Sandy loam

0

1

2

3

4

5

6

0 20 40 60 80 100Drain spacing (m)

P lo

ads

(kg/

ha/y

r)

. TPTPPTDP

0

0,4

0,8

1,2

0 20 40 60 80 100Drain spacing (m)

P lo

ads

(kg/

ha/y

r)

TDP

TPP

TP

(a) Site 1 (b) Site 2

Simulated P Concentrations in Surface Runoff for  Different Drain Spacings

Sandy clay loam Sandy loam

Watershed BMP selection - SWAT Modelling

40

50

60

70

80

90Pasture

Alfalfa

Corn2Past2

Corn2 Alfalfa2

Corn3Past

Actual

Corn2Soy2

Corn2 SoyGrn

CornSoyGrnPast

Corn Mono

0.00.51.01.52.02.53.03.54.0Pasture

Alfalfa

Corn2Past2

Corn2Alfalfa2

Corn3Past

Actual

Corn2Soy2

Corn2SoyGrn

CornSoyGrnPast

CornMono

0.46

0.48

0.50

0.52

0.54

0.56

0.58

Pasture

Alfalfa

Corn2Past2

Corn2Alfalfa2

Corn3Past

Actual

Corn2Soy2

Corn2SoyGrn

CornSoyGrnPast

CornMono

0.0

0.5

1.0

1.5

2.0Pasture

Alfalfa

Corn2Past2

Corn2Alfalfa2

Corn3Past

Actual

Corn2Soy2

Corn2SoyGrn

CornSoyGrnPast

CornMono

Management Practice ScenariosRunoff Ratio Sediment

Total PhosphorusNitrate-nitrogen

Conventional Conservation No Till

THANK YOU!A special thanks to all my graduate students, postdocs, and research assistants.

I acknowledge all our funding agencies particularly NSERC, CFI, FQRNT, Max Bell Foundation.

Water table management

• Subirrigation• Controlled drainage• Water quality benefits• Agronomic benefits

Drained Vs Undrained Fields20 May, 2006 Event Concentrations

0

100

200

300

400

500

600

700

800

VER-SRO-COMP GAG-SS-COMP MES-SRO-GRAB MAR-SS-COMP

Sample

Con

cent

ratio

n (u

g/l f

or P

, mg/

l for

MES

)

MES P-BIO P-ORTHO P DISS P TOTAL

Undrained; surface runoff)

Undrained; surface runoff)

Drained; subsurface drainage)

Drained; subsurface drainage)