soil and water conservation research under intensive

Agriculture andAgri-Food Canada

Agriculture etAgroalimentaire Canada

Canada

Soil and Water Conservation Research underIntensive Potato Production Systems in

New BrunswickT. L. Chow1, H.W. Rees1, and J.-L, Daigle 2

Quebec – New Brunswick Technical Exchange WorkshopSaint-Hyacinthe, Quebec

January 20-21, 2008

1 Potato Research Centre, AAFC, Fredericton, NB2 Eastern Canada Soil and Water Conservation Centre, Grand Falls, NB

1



Canada

Cooperators:NB Dept of Agriculture, Fisheries and AquacultureEastern Canada Soil and Water Conservation CentreEnvironment Canada (pesticides)Health Canada (pathogens) New Brunswick Department of EnvironmentUniversity of New Brunswick (modeling)Various farm agencies and associations

Potatoes New BrunswickNew Brunswick Soil and Crop Improvement Association

Individual farmer/producers



Canada

Content:IntroductionFactors causing soil erosion by waterMaterials and MethodsMagnitude of the ProblemManagement ConsiderationsConclusions



Canada

New BrunswickMaine

USA

Prince Edward Island

Potato Producing Areas- 20,000 ha annually- 30- 40 % of total farm cash receipts

Bay of Fundy

Quebec

Nova Scotia

Water Erosion

Black Brook Experimental Watershed



Canada

Shallow Soils Sloping Topography Major Rain Storms Snow Melt

SOIL EROSION

Natural Factors



Canada

Continuous potato production

Intensification of agricultural practicesExtensive tillage Heavy machinery

1940’s 1980’s

Changing field sizes

9

2000’s



Canada

• Rainfall simulator plots (1m x 1m);

• Permanent runoff-erosion plots (10m x 30m);

• Paired drainage basins – benchmark sites (2-5 ha);

• Experimental watersheds (15 and 340 km2)

Soil Erosion Research inPotato Production in New Brunswick

Off-farm

On-farm

11



Canada

Guelph Rainfall Simulator IINot weather dependentAllows for numerous treatment

comparisons and replicates

Rainfall simulator plots (1m x 1m)

12



Canada

Permanent runoff-erosion plots (10m x 30m)

Seven hydrologically isolated plots.Collection trough at lower end.Three above-ground over-flow tanks.Insulated for year-round data collection.

13



Canada

Soil Quality Monitoring Benchmark Sites

Paired drainage basins (2-5 ha)

14



Canada

Experimental watersheds

19

Little River Watershed (2000):Size : 340 km2

Land use:Agriculture – 15%Forestry – 85%

Black Brook Watershed (1992):Size : 14.5 km2Land use:

Agriculture – 64%Forestry – 36%

Monitoring stations on Little River



Canada

Magnitude of the problem

28

CROP ROTATION

CROP ROTATION

CROP ROTATION

0

5

10

15

20

25

Soi

l Los

s (t/

ha/y

r)

Potato Barley Clover TolerableCrop

20+

1 0.1

6

Potential soil loss from various crops plantedup-and-down 5-10% slope



Canada

Timing of the problem

28

00

2020

4040

6060

8080

100100

Ann

ual v

alue

(%)

Ann

ual v

alue

(%)

Soil LossSoil Loss RunoffRunoffCropping SeasonCropping Season Non-cropping SeasonNon-cropping Season

Seasonal distribution soil loss/runoffSeasonal distribution soil loss/runoffunder potato, Grand Falls, N.B.under potato, Grand Falls, N.B.

0

100

200

300

400

Eros

ivity

(MJ

mm

ha-1

h-1)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecMonth (1995-1999)



Canada


00

2020

4040

6060

8080

%

%

SandSand SiltSilt ClayClay OMOM

Eroded sedimentsEroded sediments Plow layerPlow layer

COMPOSITION OF ERODED SEDIMENTSCOMPOSITION OF ERODED SEDIMENTS



Canada


1.85

1.90

1.95

2.00

2.05%

Soi

l Org

. C

P/O R P P B P B-C C P P BrCrop

Change in SOC (0-15cm) 1989-1999Potato Up and Down Slope

1989 1999

Crop LegendB Barley P PotatoC Clover R RyegrassO Oats r ryegrass

underseeded



Canada


Nutrient Losses from potato plantedup & down 8% slope

Kg Ha-1

N P2O5 K2O Ca Mg

49 9 160 9 9



Canada




Canada


Off-Farm Implications

Sediment in road ditches

Stream water quality



Canada


Surface Water Quality

0 0 5 5

10 10 15 15 20 20 25 25 30 30

0 0 60 60 120 120 180 180 240 240 300 300 360 360 JULIAN DAYJULIAN DAY

19921992 19931993 19941994

SEDIMENT CONC ('000 ppm)SEDIMENT CONC ('000 ppm)WEIR #1WEIR #1

0 0

3 3

6 6

9 9

12 12

0 0 60 60 120 120 180 180 240 240 300 300 360 360 JULIAN DAYJULIAN DAY

19921992 19931993 19941994

NITRATE CONC (ppm)NITRATE CONC (ppm)WEIR #1WEIR #1



Canada

Impact of potato production on soil profile characteristicsWang et al 1984

50 cm

Forest soilForest soil

42 cm

SUBSOILSUBSOIL

Cultivated soil,Cultivated soil,potato rotationpotato rotation

• 93% HFP

• 7% DYB

• 27% HFP

• 22% DYB

• 51% HR



Canada

Research on potato production cultural

practices that impact on soil erosion



Canada

Some management considerations

Stones are a liability, but arethey also an asset ?



Canada


Some farmers no longer remove stones. Stones brought up in the harvester are crushed (< 2.5 cm dia.) and return to the field.

00

2020

4040

6060

8080

100100

Soi

l Los

s R

atio

(%)

Soi

l Los

s R

atio

(%)

00 55 1010 1515 2020 2525Coarse Fragment (2-5 cm dia, % vol)Coarse Fragment (2-5 cm dia, % vol)

Effects of Coarse Fragment ContentEffects of Coarse Fragment Contenton Soil Losson Soil Loss



Canada

Some management considerationsSince potato produces limited crop residue (< 1 t ha-1) for ground

cover, alternate means of enhancing SOC are considered.

Fall application of 4.5 t ha-1 hay mulch with shallow incorporation into the plow layer prior to planting the following spring acts as both a surface mulch during the winter and a soil amendment during the growing season. Soil loss is reduced by up to 90%.



Canada


20 t ha-1 dry pulp fibre added as a soil amendment reduced runoff and soil loss to 65 and 43% of control

Pulp Fibre



Canada

Some management considerationsUnderseeding grains with a grass or legume increases soil organic matter in a Potato-Grain rotation



Canada


Additional surface residues left by chisel plowing reduced runoff by 20% and soil loss by 62% on 11% slopes in grain production.

Chisel Plowing vs Moldboard Plowing



Canada


Potatoes are hilled:- for weed control- to reduce the amount

of soil to be handledwhen harvesting

- to prevent sun scalding

Effects of potato hilling on soil loss



Canada


Hilling increased soil loss 4x. The USLE C-Factor used for continuous potato is 0.52. Our research determined a value closer to 2.00

Effects of potato hilling on soil loss

To reduce impact of hilling:- reduce time soil is hilled- reduce hill side-slope angle- reduce number of hills



Canada

2005 BMP Implementation – Sub-basins #6 & 7Grassed Riparian Buffer Zones

Grassed Buffer Zone

Existing Weir

Grassed

Waterway

5-15 m grassed buffers

Before

After

New Weir



Canada

Vegetated Buffer Strip

0

1

2

3

4

Dis

char

ge R

ate

(l/s)

0

2

4

6

30 m

in In

tens

ity (m

m/h

r)

200 250 300 350 400 450 500Time (min)

Before buffer stripAfter 15 m buffer strip

June 21, 2006

Cumulative Rainfall = 6.9 mm



Canada

Vegetative Buffer Strip

0

20

40

60

80

100 C

once

ntra

tion

(mg/

l)

1 2 3 4 5 6Element

Before

After

Buffer Strip June 21, 2006

NO3 K Ca Mg SedP

ug/l

g/l



Canada

Vegetated Buffer Strip

0

10

20

30

Dis

char

ge R

ate

(l/s)

0

20

40

60

30 m

in In

t ens

ity (m

m/ h

r)

900 1000 1100 1200 1300 1400 1500 1600 1700 1800Time (min)

Before buffer stripAfter 15 m buffer strip

July 10, 2006Cumulative Rainfall = 28.5 mm



Canada

Some management considerationsContour cultivation

-not always logistically possible (complex slopes)

- longer field slope lengths reduce effectiveness

Up-and-down slope cultivation

Contour cultivation

24.3 t ha-1 vs 1.2 t ha-1

(soil loss based on 30 m slope length – erosion plots)



Canada


Variable grade

diversions and grassed waterways



Canada


FloodPrevention

0

20

40

60

80

100

120

Dis

char

ge R

ate

(l/s)

04080

120160200

Rai

nfal

l Int

e nsi

ty (m

m/h

)

0 40 80 120 160 200 240

Time of Day (minutes)

0 40 80 120 160 200 240

Up-and-down slope cultivationDiversion terraces and grassed waterway

June 19, 1994



Canada


Up and Down Variable Grade DiversionsSlope Cultivation and Grassed Waterways

- 5% slope - 6.4% slope- 250 m slope length - 66 m between diversions

Soil Loss 20.8 +/- 3.8 1.0 +/- 0.6(t ha-1 yr-1)

Runoff (cm) 18.1 +/- 1.8 2.5 +/- 1.2(% of May to (29%) (4%)Nov. Rainfall.)

Benefits of variable grade diversions and grassed waterway conservation systems in potato production



Canada

Total Available N and P Losses

0

10

20

30

40

kg/h

a

Total N Total P

37.2

28.1

1.7 0.4

Up-Down Cultivation Diversions/Waterway

(Potato 1994)



Canada

Area of fields protected byterraces/grassed waterways:

1992 - 147 ha (16% of farm land)

2003 - 321 ha (35% of farm land)



Canada

Black Brook Experimental Watershed

Surface water

monitoring sites

Automated stage height recording

and water sampling for

flow, pH, conductivity,

sediment loading, N, P, K,

Ca, Mg



Canada

Impacts of Terracing on Stream Discharge

30

40

50

60

70

80

%

92 93 94 95 96 97 98 99 00 01 02Year

Black Brook WatershedDischarge as a % of Precipitation

2

4

6

8

10

12

Cub

ic m

eter

s ('0

00,0

00)

1992-1994 1998-2002Period

10.9

7.1

Black Brook WatershedStream Discharge



Canada

Impacts of Terracing onStream Sediment Load

0

2

4

6

8

10

Ton/

MJ

mm

/ha

hr y

r

92 93 94 95 96 97 98 99 00 01 02Year

Black Brook WatershedSediment per unit Erosivity

Impacts of

Construction

010002000300040005000600070008000

Ton

1992-1994 1998-2002Period

6544

3655

Black Brook WatershedSediment Yield



Canada

Conclusions:Landscape, soil and climate conditions of NB are susceptible to soil erosion by water; Intensive potato production enhances the erosion processes;Soil erosion induces on-farm and off-farm impacts;Soil conservation practices (BMPs) reduce these impacts;Soil conservation should consider a group of BMPs rather than any single practices; Watershed studies indicate positive returns of BMPs in term of discharge and sediment loading;BMPs are the key solution to the sustainable potato production in NB



Canada31

THANK YOU

[email protected]

soil and water conservation research under intensive

Documents