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David A. Lobb Department of Soil Science University of Manitoba
Summit on Canadian Soil Health Soil Conservation Canada August 23rd, 2017 Guelph, Ontario
SOIL DEGRADATION: THE COST TO AGRICULTURE AND THE ECONOMY
ACKNOWLEDGEMENTS
Contributors:
Nasem Badreldin, University of Manitoba Marita Loro, Queens University Derek Brewin, University of Manitoba Tim Martin, Agriculture and Agri-Food Canada Brian McConkey, Agriculture and Agri-Food Canada Sheng Li, Agriculture and Agri-Food Canada
BACKGROUND
Question:
Why is a soil scientist talking about the economics of soil degradation?
To ensure sustainable crop food production at the farm scale and at the industry scale, by providing information on soil degradation and soil conservation in its most impactful form, economic.
BACKGROUND
Past Assessments of Costs: The costs of soil degradation in Canada were last assessed in the early 1980s.
Don F. Rennie’s 1985 paper: “Soil and Water Issues and Options in Canada”
Murray H. Miller’s 1986 paper "Soil Degradation in Eastern Canada: Its Extent and Impact”
BACKGROUND
annual values present values, 2.05x
With respect to public awareness, to government support through policies and programs, and to industry action, there has been a steady decline in interest in soil conservation.
A pervasive belief that “we know all there is to know about soil erosion and soil conservation”. And, that “the job is done and we need to move on”. A sense of fatigue has set in.
BACKGROUND
Move to justify soil conservation through protection of water quality and climate change.
BACKGROUND
There is a need to revisit these figures, to improve them and to update them to assess status and progress.
There is a more complete and accurate understanding of soil degradation processes – better models for assessment and prediction.
There are more comprehensive and accurate databases – which serve as better model inputs/outputs for assessment and prediction.
ASSESSMENT OF COST
Soil Degradation Processes: Focus on soil erosion given its extent and severity.
ASSESSMENT OF COST
Economic Impacts: Focus on the direct impacts of soil erosion on crop production and market value.
Not the indirect impacts.
Not the off-field impacts.
ASSESSMENT OF COST
Assessment and Prediction Models: Agri-Environmental Indicators Models: AAFC’s AEIP, NAHARP, SMP
Methods: Assessment and Prediction Models
National Agri-Environmental Health Analysis and
Reporting Program (NAHARP)
Integrate
Economics Agri-Environmental
Indicator (AEI)
Environmental
Valuation
Soil Quality
Soil Salinity
Tillage Erosion
(TillERI) Water Erosion
(WaterERI)
Wind Erosion
(WindERI) Total Soil Erosion
(SoilERI)
Soil Organic
Carbon Soil Erosion
+ + =
Water Quality Air Quality Others
Trace Elements
Soil Landscape Canada (SLC) Polygon, 10,000 – 1,000,000 ha
TillERI
Erosion Models
Landform
National Soil
Database
(NSDB)
Census of
Agriculture
1981- 2016
Soil,
Topography
Climate
Stations
Long Term
Climate Data Crop type,
Tillage
Up
Mid
Low Dep
WaterERI WindERI
SoilERI
Province
Canada
Data inputs
Aggregation
Aggregation
Aggregation
Methods: the framework of SoilERI
Methods: source data
• Soil
– National Soil Database (NSDB), SLC polygons
• Land use
– Census of agriculture
• 1981 - 2016
– Crop type
• Corn, cereal, forage …
– Tillage system
• Conventional
• Conservation
• No-till (direct-seeding)
• Climate
– Long term climate stations
• Topography
– Nominal info in NSDB and SLC polygon • Landform type: surface form and slope class
– Terrain analyses of typical sites • Nominal topo info to two-dimensional hillslopes
National Soil
Database
(NSDB)
Census of
Agriculture
1981- 2006
Soil,
Topography
Climate
Stations
Long Term
Climate Data Crop type,
Tillage
Methods: source data
849
89
162 Ecoregions
Ecodistric ts
Ecozones
SLC Polygons (#89 = 0.13 million ha)
Canada
(#849 = 0.9 million ha)
(#162 = 3.3 million ha)
(Prairie = 6.5 million ha)
Figure1: Map of the province of Manitoba illustrating the spatial framework of biophysical data in Canada. Source: Agriculture and Agri-food Canada.
Agriculture and Agri-Food CanadaAgriculture et Agroalimentaire Canada
Manitoba
0 250 500 1000
Projection Azimutal de Equi-aire de Lambert
0 500250 750 1000 1500
Lambert Azimuthal Equal Area Projection
ECHELLE ESCALA SCALE1: 45 000 000
miles
Kms.
Proyeccion Azimultal de Equi-area de Lambert
15
1
1
1
1
2
2
2
2
2
2
2
7
7
3
6
3
3
5
55
5
5
5
5
8
9
9
6
10
6
7
7
11
10
10
6
13
12
13
12
14
13
14
15
14
14
4
COMMISSION DE
CO
COMISION PARA LA
COOPERACION AMBIENTAL
COMMISSION FOR
ENVIRONMENTAL COOPERATION
CCE
CCA
CEC
OP RATION ENVIRONNEMENTAL
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
NIVEAU I. NIVEL I. LEVEL I
CORDILLERE ARCTIQUECORDILLERA ARTICAARCTIC CORDILLERA
TOUNDRATUNDRATUNDRA
TAIGATAIGATAIGA
PLAINE D'HUDSONPLANICIE DE HUDSONHUDSON PLAIN
FORETS SEPTENTRIONALESBOSQUES SEPTENTRIONALESNORTHERN FORESTS
MONTAGNES FORESTEES DU NORD-QUESTMONTANAS BOSCOSAS NOROCCIDENTALESNORTHWESTERN FORESTED MOUNTAINS
FORET MARITIME DE LA COTE OCCIDENTALEBOSQUE COSTERO OCCIDENTALMARINE WEST COAST FOREST
FORETS TEMPEREES DE L'ESTBOSQUES TEMPLADOS DEL ESTEEASTERN TEMPERATE FORESTS
GRANDES PLAINESGRANDES PLANICIESGREAT PLAINS
DESERTS DE L'AMERIQUE DU NORDDESIERTOS DE NORTEAMERICANORTH AMERICAN DESERTS
CALIFORNIE MEDITERRANEENNECALIFORNIA MEDITERRANEAMEDITERRANEAN CALIFORNIA
HAUTES TERRES SEMI-ARIDES MERIDIONALESELEVACIONES SEMIARIDAS MERIDIONALESSOUTHERN SEMI-ARID HIGHLANDS
SIERRAS TEMPEREESSIERRAS TEMPLADASTEMPERATE SIERRAS
FORETS TROPICALES SECHESSELVAS CALIDO-SECASTROPICAL DRY FORESTS
FORETS TROPICALES HUMIDESSELVAS CALIDO-HUMEDASTROPICAL WET FORESTS
Limite internationaleLimite internacionalInternational boundary
Limite de regions Niveau ILimite de regiones Nivel IRegion boundary Level I
Figure 2: Ecozones of North America. Source: Commission for Environmental Cooperation.
Methods: landform model • 19 landform types
– 7 surface forms
– 1 – 4 slope classes
• 4 segments (some only have 3)
– Up, Mid, Low and Dep
– length and slope gradient
• Calculation unit:
– Landform (hillslope)
– Multiple hillslopes in one SLC polygon
• Allocation
– Soil, crop type, tillage system
– Each segment in each landform
Landform
Up
Mid
Low Dep
Methods: wind erosion (WindERI)
• Equation
– Wind Erosion Equation (WEQ)
– AWd = f(I,K,C,L,V)
• Individual factors
– C-, L- and V-factor for the hillslope
– I- and K-factor for each segment
• Adjustments
– Expert knowledge
○ Processes and conditions in Canada
Landform
Up
Mid
Low Dep
TillERI
Erosion Models
WaterERI WindERI
SoilERI
Methods: water erosion (WaterERI)
• Equation
– Universal Soil Loss Equation (USLE)
– ATi = R • K • LS • C • P
• Individual factors --- RUSLE
– R-, C- and P-factor for the hillslope
– K- and LS-factor for each segment
• Adjustments --- RUSLE2
– Interactions between factors
– Soil accumulation rates
– Regression equations
• Intensive test runs in RUSLE2
Landform
Up
Mid
Low Dep
TillERI
Erosion Models
WaterERI WindERI
SoilERI
Methods: tillage erosion (TillERI)
• Equation
– ATi = ET • EL
• Erosivity of tillage ET
– Crop type and tillage system
○ Tillage equipment
○ Number of passes per year
– Field experiment data
• Erodibility of Landform EL
– Slope gradient and slope length
Landform
Up
Mid
Low Dep
TillERI
Erosion Models
WaterERI WindERI
SoilERI
soil loss
soil
accumulation
soil
accumulation
Tillage erosion is the net redistribution (losses and gains) of soil resulting from the
variability in the movement of soil by tillage.
Cropping and tillage systems that employ intensive tillage (frequent, deep, fast)
can cause severe tillage erosion.
20
ET
Methods: integrated soil erosion (SoilERI) • SoilERI model
– ASoil = ATi + AWt + AWd – For each segment in each landform
(hillslope)
• Aggregation
– Area-weighted across
○ Landform
○ Crop type
○ Tillage system
– Value for each segment
○ SLC polygon
○ Province
○ Canada
Landform
Up
Mid
Low Dep
Soil Landscape Canada (SLC) Polygon, 10,000 – 1,000,000 ha
TillERI
Erosion Models
WaterERI WindERI
SoilERI
Province
Canada
Aggregation
Aggregation
Aggregation
ASSESSMENT OF COST
Assessment and Prediction Models:
Classes of Soil Erosion / Degree of Soil Loss:
Results: Average annual soil loss rate for each SLC polygon, landform segment, soil, crop group and tillage system Mapped as most eroding segments (upper and mid slopes) Reported as share (%) of land in each class, rolled up to Province and Canada
Extremely Low / Negligible 0 – 3 t ha-1 yr-1
0 – 6 t ha-1 yr-1
6 – 11 t ha-1 yr-1
11 – 22 t ha-1 yr-1
22 – 33 t ha-1 yr-1
>33 t ha-1 yr-1
} Sustainable
ASSESSMENT OF COST
Distribution of Soil Loss Rates for 1971 and 2011: Wind Erosion
1971
2011 Soil Erosion Risk Classes
* Upper slopes
ASSESSMENT OF COST
Distribution of Soil Loss Rates for 1971 and 2011: Water Erosion
1971
2011 Soil Erosion Risk Classes
* Upper + Mid slopes
ASSESSMENT OF COST
Distribution of Soil Loss Rates for 1971 and 2011: Tillage Erosion
1971
2011 Soil Erosion Risk Classes
* Upper slopes
ASSESSMENT OF COST
Distribution of Soil Loss Rates for 1971 and 2011: Soil Erosion
Soil Erosion Risk Classes
1971
2011
* Upper + Mid slopes
ASSESSMENT OF COST
Provincial Overview of Soil Erosion Between 1971 and 2011: Wind, Water and Tillage Erosion, combined as Soil Erosion
Negligible Very Low Low Moderate High Very High
1971 2011 1971 2011 1971 2011 1971 2011 1971 2011 1971 2011
BC 17.1 54.6 22.9 32.4 48.3 9.0 8.6 1.9 0.4 0.5 2.6 1.6
AB 20.9 65.8 32.5 20.3 13.3 10.3 20.2 3.2 7.0 0.3 6.0 0.0
SK 0.0 60.1 19.5 22.7 44.2 15.9 17.2 1.2 15.3 0.0 3.7 0.0
MB 4.2 15.5 37.6 55.7 23.2 19.2 29.5 9.3 5.0 0.3 0.6 0.0
ON 5.5 10.0 16.4 17.8 10.4 14.5 25.0 29.0 18.6 15.4 24.0 13.4
QC 56.8 53.1 16.9 22.5 11.4 11.5 10.6 9.7 2.8 1.6 1.6 1.5
NB 20.6 27.4 21.1 16.0 32.9 33.7 7.9 9.6 7.0 6.5 10.4 6.9
NS 7.2 9.9 15.3 38.9 36.5 33.6 38.3 15.6 1.6 1.6 1.2 0.4
PE 11.5 11.9 7.5 7.9 4.1 3.9 65.7 76.3 11.2 0.0 0.0 0.0
NF 2.7 16.6 11.6 14.5 13.8 6.2 5.9 39.9 25.7 22.8 40.4 0.0
Can 9.4 50.5 24.9 25.6 28.9 14.4 20.0 6.3 11.3 1.7 5.5 1.4
ASSESSMENT OF COST
Provincial Overview of Soil Erosion between 1971 and 2011: Wind, Water and Tillage Erosion, combined as Soil Erosion
Negligible Very Low Low Moderate High Very High M to VH
1971 2011 1971 2011 1971 2011 1971 2011 1971 2011 1971 2011 1971 2011
BC 17.1 54.6 22.9 32.4 48.3 9.0 8.6 1.9 0.4 0.5 2.6 1.6 11.7 4.0
AB 20.9 65.8 32.5 20.3 13.3 10.3 20.2 3.2 7.0 0.3 6.0 0.0 33.3 3.6
SK 0.0 60.1 19.5 22.7 44.2 15.9 17.2 1.2 15.3 0.0 3.7 0.0 36.2 1.2
MB 4.2 15.5 37.6 55.7 23.2 19.2 29.5 9.3 5.0 0.3 0.6 0.0 35.1 9.6
ON 5.5 10.0 16.4 17.8 10.4 14.5 25.0 29.0 18.6 15.4 24.0 13.4 67.7 57.8
QC 56.8 53.1 16.9 22.5 11.4 11.5 10.6 9.7 2.8 1.6 1.6 1.5 14.9 12.9
NB 20.6 27.4 21.1 16.0 32.9 33.7 7.9 9.6 7.0 6.5 10.4 6.9 25.3 22.9
NS 7.2 9.9 15.3 38.9 36.5 33.6 38.3 15.6 1.6 1.6 1.2 0.4 41.1 17.6
PE 11.5 11.9 7.5 7.9 4.1 3.9 65.7 76.3 11.2 0.0 0.0 0.0 76.9 76.3
NF 2.7 16.6 11.6 14.5 13.8 6.2 5.9 39.9 25.7 22.8 40.4 0.0 71.9 62.7
Can 9.4 50.5 24.9 25.6 28.9 14.4 20.0 6.3 11.3 1.7 5.5 1.4 36.8 9.5
ASSESSMENT OF COST
Soil Loss and Yield Loss Relationship:
0
10
20
30
40
50
60
70
80
90
100
0102030405060708090100
Amount of original topsoil remaining (%SOC)
Cro
p y
ield
(%
)
2 x D
T
1 x D
T
Non-linear response
ASSESSMENT OF COST
ASSESSMENT OF COST
1971 2011
Units
Low-Eroding Cropland (N-L)
High-Eroding Cropland (M-VH)
Total Low-Eroding Cropland (N-L)
High-Eroding Cropland (M-VH)
Total
Cropland Area ha 25,149,351 14,663,025 39,812,376 35,211,104 3,676,329 38,887,434
% 63.2 36.8 100 90.5 9.5 100
63.2 9.5
Soil Loss Rate t ha-1 yr-1 5.9 24.0 3.5 22.7
Relative Crop Yield % 99.5 83 95 40
Crop Yield Loss % 0.5 17 5 60
Annual Soil Loss and Crop Yield Loss in 1971 and 2011
ASSESSMENT OF COST
1971 2011
Units
Low-Eroding Cropland (N-L)
High-Eroding Cropland (M-VH)
Total Low-Eroding Cropland (N-L)
High-Eroding Cropland (M-VH)
Total
Cropland Area ha 25,149,351 14,663,025 39,812,376 35,211,104 3,676,329 38,887,434
% 63.2 36.8 100 90.5 9.5 100
63.2 9.5
Soil Loss Rate t ha-1 yr-1 5.9 24.0 3.5 22.7
Relative Crop Yield % 99.5 83 95 40
Crop Yield Loss % 0.5 17 5 60
Degraded Value $2016 13,570,289,11
6 27,326,006,31
6
Non-Degraded Value $2016 14,525,640,87
3 30,429,706,92
1
Lost Value $2016 $0.96 B yr-1 $3.1B yr-1
Cumulative loss up to 1971 in the order of $20-30B
… and Lost Value
ASSESSMENT OF COST
1971 2011
Units
Low-Eroding Cropland (N-L)
High-Eroding Cropland (M-VH)
Total Low-Eroding Cropland (N-L)
High-Eroding Cropland (M-VH)
Total
Cropland Area ha 25,149,351 14,663,025 39,812,376 35,211,104 3,676,329 38,887,434
% 63.2 36.8 100 90.5 9.5 100
63.2 9.5
Soil Loss Rate t ha-1 yr-1 5.9 24.0 3.5 22.7
Relative Crop Yield % 99.5 83 95 40
Crop Yield Loss % 0.5 17 5 60
Degraded Value $2016 13,570,289,11
6 27,326,006,31
6
Non-Degraded Value $2016 14,525,640,87
3 30,429,706,92
1
Lost Value $2016 $0.96 B yr-1 $3.1B yr-1
Cumulative loss up to 1971 in the order of $20-30B Cumulative loss from 1971 to 2016 in the order $40-60B
… and Lost Value
ASSESSMENT OF COST
Why has the cost of soil erosion continue to increase since the 1970s and 1980s rather than decrease???
• Even areas where soil erosion is now controlled through soil conservation practices suffer from historical losses of soil.
• Restoring soil productivity on moderately to severely eroded areas is an extremely slow process.
• Cumulative soil losses have pushed yield losses into dramatic declines.
• Although the area of moderately to severely eroded area has decreased in general, a considerable amount of area has not, and on these areas higher value crops are grown.
• The value of crop production has increased. Growing higher value crops on more erodible land.
ASSESSMENT OF COST Average Soil Loss Rate (t ha-1 yr-1) in 2011 by Landform Type
Landform Cropland Area Integrated Tillage Water Wind
(ha) Upper Mid Upper Mid Upper Mid Upper Mid
Hummocky Slight 3,856,887 2.5 1.2 1.6 0.0 0.2 0.5 0.7 0.7
Gentle 4,071,743 7.4 2.0 6.1 0.0 0.5 1.5 0.7 0.5
Moderate 1,076,083 16.7 9.4 13.1 0.0 2.9 9.1 0.7 0.3
Steep 334,848 24.6 20.9 15.2 0.0 8.6 20.6 0.8 0.3 Inclined Slight 791,366 2.6 3.1 0.4 0.0 0.3 0.8 2.0 2.2
Gentle 908,393 2.7 3.5 0.8 0.0 0.9 2.5 1.0 1.0
Moderate 85,668 6.7 7.1 3.0 0.0 1.8 5.2 1.8 2.0
Steep 163,461 12.2 7.2 8.6 0.0 2.3 5.9 1.4 1.5
V Steep 86,253 24.7 11.3 20.5 0.0 3.4 10.5 0.8 0.8 Level Level 4,101,628 4.1 3.6 0.7 0.0 0.8 1.0 2.6 2.6
Rolling Gentle 1,892,458 3.5 5.1 1.6 0.0 1.4 4.8 0.5 0.3
Moderate 771,942 13.5 23.7 2.6 0.0 10.3 23.4 0.6 0.3
Steep 62,303 20.6 29.3 4.8 0.0 15.5 29.2 0.3 0.1 Ridged Slight 214,399 1.1 1.1 0.3 0.0 0.2 0.5 0.6 0.6
Gentle 342,561 3.0 2.9 0.6 0.0 0.6 1.8 1.8 1.1
Moderate 35,068 12.7 22.5 5.4 0.0 7.3 22.5 0.0 0.0 Steep 70,315 7.8 4.3 3.9 0.0 1.4 3.8 2.5 0.5
Undulating Slight 14,569,503 2.2 1.6 0.9 0.0 0.2 0.6 1.0 1.0
Gentle 5,369,683 7.5 6.3 5.1 0.0 1.7 5.8 0.7 0.5
FUTURE RESEARCH
Refinement of the methods:
• Enhanced temporal resolution: Estimate soil loss rates on an annual basis, rather than every five years.
• Enhanced spatial resolution: Application of remotely sensed data and the estimation of soil loss rates on a raster basis rather than a polygon basis.
• More comprehensive relationships between soil loss and loss in crop yield.
• Develops relationships for a range of climate scenarios.
FUTURE RESEARCH
Refinement of the methods:
• Develop highly descriptive tillage profiles to account for variations in tillage equipment associated with climatic regions, soil types, cropping systems and for variations over time.
• Develop highly descriptive cropping profiles to account for variations in tillage equipment associated with climatic regions, soil types, and for variations over time.
• Use probabilities rather than means to describe to better represent likelihoods and uncertainties.
Soil erosion continues to cost Canadian agriculture and the economy substantially.
Although soil conservation efforts have reduced the amount of cropland that is moderately to severely eroded, more needs to be done!
TAKE HOME MESSAGE
Efforts need to be reinvigorated; they need to be smarter; efforts need to be targeted, appropriate to soil and landscapes, climate and cropping systems.
This requires commitment and investment in Discovery and Innovation by all stakeholders.
We need to think more broadly about what tillage is and what conservation tillage is.
There are tillage operations that
are more erosive than the
mouldboard plough
THE WAY FORWARD
We must consider how far soil is moved
during tillage as well as how much crop
residue is left on the soil surface
We need to think more broadly about what tillage is and what conservation tillage is.
There are tillage operations that
are more erosive than the
mouldboard plough
THE WAY FORWARD
We must consider how far soil is moved
during tillage as well as how much crop
residue is left on the soil surface
We need to think more broadly about what tillage is and what conservation tillage is.
THE WAY FORWARD
Even seeding operations
cause tillage erosion
We need to think more broadly about what tillage is and what conservation tillage is.
THE WAY FORWARD
Even crop management operations
cause tillage erosion
We need to think more broadly about what tillage is and what conservation tillage is.
THE WAY FORWARD
A mouldboard plough can be
used as a soil conservation tool
Conservation tillage simply reduces the loss of soil organic carbon and productivity, we must focus on good crop management to increase organic carbon inputs into the soil and increase soil and crop productivity.
THE WAY FORWARD
Soil-Landscape Restoration
Returning eroded soil to the top of
the slope in France in the 1930s
THE WAY FORWARD
More soil research needs to be carried out at the landscape scale.
THE WAY FORWARD