Post on 07-Dec-2021
Agriculture andAgri-Food Canada
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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
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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
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Content:IntroductionFactors causing soil erosion by waterMaterials and MethodsMagnitude of the ProblemManagement ConsiderationsConclusions
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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
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Shallow Soils Sloping Topography Major Rain Storms Snow Melt
SOIL EROSION
Natural Factors
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Continuous potato production
Intensification of agricultural practicesExtensive tillage Heavy machinery
1940’s 1980’s
Changing field sizes
9
2000’s
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• 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
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Guelph Rainfall Simulator IINot weather dependentAllows for numerous treatment
comparisons and replicates
Rainfall simulator plots (1m x 1m)
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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.
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Soil Quality Monitoring Benchmark Sites
Paired drainage basins (2-5 ha)
14
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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
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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
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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)
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Magnitude of the problem
00
2020
4040
6060
8080
%
%
SandSand SiltSilt ClayClay OMOM
Eroded sedimentsEroded sediments Plow layerPlow layer
COMPOSITION OF ERODED SEDIMENTSCOMPOSITION OF ERODED SEDIMENTS
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Magnitude of the problem
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
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Magnitude of the problem
Nutrient Losses from potato plantedup & down 8% slope
Kg Ha-1
N P2O5 K2O Ca Mg
49 9 160 9 9
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Magnitude of the problem
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Magnitude of the problem
Off-Farm Implications
Sediment in road ditches
Stream water quality
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Magnitude of the problem
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
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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
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Research on potato production cultural
practices that impact on soil erosion
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Some management considerations
Stones are a liability, but arethey also an asset ?
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Some management considerations
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
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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%.
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Some management considerations
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
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Some management considerationsUnderseeding grains with a grass or legume increases soil organic matter in a Potato-Grain rotation
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Some management considerations
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
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Some management considerations
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
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Some management considerations
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
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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
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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
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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
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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
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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)
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Some management considerations
Variable grade
diversions and grassed waterways
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Some management considerations
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
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Some management considerations
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
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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)
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Area of fields protected byterraces/grassed waterways:
1992 - 147 ha (16% of farm land)
2003 - 321 ha (35% of farm land)
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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
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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
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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
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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