Co$t of $oil Ero$ion
Rick Cruse
Scott Lee
Tim Sklenar
Iowa State University
The True Cost of American Food
14-17th April 2016
Fort Mason Center – San Francisco
What does it cost?
What does it cost? And who pays?
On site costs
What does it cost? And who pays?
Off Site costs
What does it cost? We know who will pay.
Global Food Security
1Bakker, M. M., Govers, G. and Rounsevell, M. D. A. 2004. The Crop Productivity-erosion
Relationship: An Analysis Based on Experimental Work. Catena, 57: 55–76
What is the relationship between soil
loss and crop yield?
• …yield reductions of approximately 4% per 10
cm (4 inches) of soil loss should be considered
realistic.1
• Where nutrient deficits are avoided by
fertilization, response curves are generally
convex, implying that reductions will become
increasingly severe with further erosion. 1
y = 26.676ln(x) + 69.797
R² = 0.5705
60.0
80.0
100.0
120.0
140.0
160.0
180.0
200.0
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0
CornYield(bu/acre)
A Horizon Depth (in)
DRY Corn Yield vs A horizon depth
Boone County. Tom Kaspar, USDA/ARS personal communication.
4.8 T/A 1.6 T/A
5.4 T/A5.4 T/A 8.0 T/A
State Wide Average
5.7 T/A/YR
One pound of soil for each pound of corn produced
y = 26.676ln(x) + 69.797
R² = 0.5705
60.0
80.0
100.0
120.0
140.0
160.0
180.0
200.0
0.0 10.0 20.0 30.0 40.0 50.0
CornYield(bu/acre)
A Horizon Depth (in)
DRY Corn Yield vs A horizon depth
Simplify, Simplify, Simplify, Simplify
• Average 2.2 bu/A yield loss/inch of topsoil
• Using Iowa average corn yield 2006-2015
▫ 170 bu/A 5% reduction per 4 inches (10 cm)
• Assume $4.00/Bu corn
• 5.7 tons soil loss/A cost producer next year
$0.35/A
Nutrient Redistribution and Loss
• Nutrient value in eroded topsoil
▫ 5.7 Tons/A
 Mostly redistributed in field
 Sediment Delivery Ratio = 0.35
 (5.7 Tons/A) X = 2 Tons/A
 (2 Tons/A) X ($2.10/Ton1) = $4.20
1Iowa Learning Farms. 2013. Cost of soil erosion. http://www.extension.iastate.edu
/ilf/sites/www.extension.iastate.edu/files/ilf/Cost_of_Eroded_Soil.pdf
Cumulativecost($/A)
Years
0
100
200
300
400
500
600
700
0 10 20 30 40 50 60
Soil Erosion ($0.35 + Nutrient1) and Conservation
Cost. Soil Erosion Rate 5.7 T/A/Yr
1Nutrient loss value $2.10/ton for exported soil
Cumulativecost($/A)
Years
0
100
200
300
400
500
600
700
0 10 20 30 40 50 60
Soil Erosion ($0.35 + Nutrient1) and Conservation
Cost. Soil Erosion rate 5.7 T/A/Yr
1Nutrient loss value $2.10/ton for exported soil
$30/A/Yr Soil
Conservation
Cumulativecost($/A)
Years
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
0 10 20 30 40 50 60
Soil Erosion ($2.45 + Nutrients1) and Conservation
Cost. Soil Erosion Rate 38.5 T/A/Yr
$30/A/Yr for
Soil Conservation
1Nutrient loss value = $28.30/A for exported topsoil
Off Site Costs???
• $12 - $38 / Acre US cropland1
1Tegtmeier, Erin M; Duffy, Michael, External Costs of Agricultural Production
in the United States, International Journal of Agricultural Sustainability
Vol. 2 no. 1 (2004): 1-20.
Between 2005 and 2014, U.S. taxpayers spent $3 billion in
Iowa through five USDA programs to pay landowners to
farm in more environmentally friendly ways.1
• Approximately $125/A for 24 million row crop
acres
• Approximately $12.50/A/Yr
1Rundquist, Soren and Craig Cox. 2016. Fooling ourselves: voluntary programs
fail to clean-up dirty water. Environmental Working Group. Washington DC.
Farm Costs ~ $ 4.55/A/YR
Off Site Damage ~ $25.00/A/YR
Public Investment ~ $12.50/A/YR
$40+/A/YR
Summary
Global Food $ecurity?????
“We’ve had the farm program since the mid-1930s,
and we do have to overproduce to help feed the world.
But we have to take care of this land. If we really have
to feed 9 billion people by 2050, we’re really going to
need this soil.”1 Seth Watkins – farmer Clarinda, IA.
Kezar, Mitch. 2016. There’s no magic bullet to stop erosion.
Commonsense practices help. Successful Farming. Available on line.
http://www.agriculture.com/content/real-world-conservation
Conclusions
• Industrial Ag - Soil conservation more expensive
than soil erosion for the farmer
▫ Soil conservation is added expense
 Unless farmer owns the land for extended time and
erosion rates are high
• Erosion cost to public is greater than cost to the
farmer

Rick Cruse - Corn/soy systems

  • 1.
    Co$t of $oilEro$ion Rick Cruse Scott Lee Tim Sklenar Iowa State University The True Cost of American Food 14-17th April 2016 Fort Mason Center – San Francisco
  • 3.
  • 4.
    What does itcost? And who pays? On site costs
  • 5.
    What does itcost? And who pays? Off Site costs
  • 6.
    What does itcost? We know who will pay. Global Food Security
  • 7.
    1Bakker, M. M.,Govers, G. and Rounsevell, M. D. A. 2004. The Crop Productivity-erosion Relationship: An Analysis Based on Experimental Work. Catena, 57: 55–76 What is the relationship between soil loss and crop yield? • …yield reductions of approximately 4% per 10 cm (4 inches) of soil loss should be considered realistic.1 • Where nutrient deficits are avoided by fertilization, response curves are generally convex, implying that reductions will become increasingly severe with further erosion. 1
  • 8.
    y = 26.676ln(x)+ 69.797 R² = 0.5705 60.0 80.0 100.0 120.0 140.0 160.0 180.0 200.0 0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0 CornYield(bu/acre) A Horizon Depth (in) DRY Corn Yield vs A horizon depth Boone County. Tom Kaspar, USDA/ARS personal communication.
  • 10.
    4.8 T/A 1.6T/A 5.4 T/A5.4 T/A 8.0 T/A
  • 11.
    State Wide Average 5.7T/A/YR One pound of soil for each pound of corn produced
  • 12.
    y = 26.676ln(x)+ 69.797 R² = 0.5705 60.0 80.0 100.0 120.0 140.0 160.0 180.0 200.0 0.0 10.0 20.0 30.0 40.0 50.0 CornYield(bu/acre) A Horizon Depth (in) DRY Corn Yield vs A horizon depth
  • 13.
    Simplify, Simplify, Simplify,Simplify • Average 2.2 bu/A yield loss/inch of topsoil • Using Iowa average corn yield 2006-2015 ▫ 170 bu/A 5% reduction per 4 inches (10 cm) • Assume $4.00/Bu corn • 5.7 tons soil loss/A cost producer next year $0.35/A
  • 14.
    Nutrient Redistribution andLoss • Nutrient value in eroded topsoil ▫ 5.7 Tons/A  Mostly redistributed in field  Sediment Delivery Ratio = 0.35  (5.7 Tons/A) X = 2 Tons/A  (2 Tons/A) X ($2.10/Ton1) = $4.20 1Iowa Learning Farms. 2013. Cost of soil erosion. http://www.extension.iastate.edu /ilf/sites/www.extension.iastate.edu/files/ilf/Cost_of_Eroded_Soil.pdf
  • 15.
    Cumulativecost($/A) Years 0 100 200 300 400 500 600 700 0 10 2030 40 50 60 Soil Erosion ($0.35 + Nutrient1) and Conservation Cost. Soil Erosion Rate 5.7 T/A/Yr 1Nutrient loss value $2.10/ton for exported soil
  • 16.
    Cumulativecost($/A) Years 0 100 200 300 400 500 600 700 0 10 2030 40 50 60 Soil Erosion ($0.35 + Nutrient1) and Conservation Cost. Soil Erosion rate 5.7 T/A/Yr 1Nutrient loss value $2.10/ton for exported soil $30/A/Yr Soil Conservation
  • 17.
    Cumulativecost($/A) Years 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 0 10 2030 40 50 60 Soil Erosion ($2.45 + Nutrients1) and Conservation Cost. Soil Erosion Rate 38.5 T/A/Yr $30/A/Yr for Soil Conservation 1Nutrient loss value = $28.30/A for exported topsoil
  • 18.
    Off Site Costs??? •$12 - $38 / Acre US cropland1 1Tegtmeier, Erin M; Duffy, Michael, External Costs of Agricultural Production in the United States, International Journal of Agricultural Sustainability Vol. 2 no. 1 (2004): 1-20.
  • 19.
    Between 2005 and2014, U.S. taxpayers spent $3 billion in Iowa through five USDA programs to pay landowners to farm in more environmentally friendly ways.1 • Approximately $125/A for 24 million row crop acres • Approximately $12.50/A/Yr 1Rundquist, Soren and Craig Cox. 2016. Fooling ourselves: voluntary programs fail to clean-up dirty water. Environmental Working Group. Washington DC.
  • 20.
    Farm Costs ~$ 4.55/A/YR Off Site Damage ~ $25.00/A/YR Public Investment ~ $12.50/A/YR $40+/A/YR Summary
  • 21.
    Global Food $ecurity????? “We’vehad the farm program since the mid-1930s, and we do have to overproduce to help feed the world. But we have to take care of this land. If we really have to feed 9 billion people by 2050, we’re really going to need this soil.”1 Seth Watkins – farmer Clarinda, IA. Kezar, Mitch. 2016. There’s no magic bullet to stop erosion. Commonsense practices help. Successful Farming. Available on line. http://www.agriculture.com/content/real-world-conservation
  • 22.
    Conclusions • Industrial Ag- Soil conservation more expensive than soil erosion for the farmer ▫ Soil conservation is added expense  Unless farmer owns the land for extended time and erosion rates are high • Erosion cost to public is greater than cost to the farmer

Editor's Notes

  • #9 10 cm erosion starting at 15 inches or 37.5 cm results in 400 kg/ha with yield of 8,946 kg/ha at 15 inches (37.5 cm) top soil depth. Is 4.5 % reduction for 10 cm loss top soil depth. Eight bushels lost with 5 inches thinning at 15 -> 10 inch depth. 12.5 cm & 504 Kg/ha. Or 40 kg/cm or 4 kg/ha/mm. Max yield ~ 170 bu/A = 10.7 tonnes/ha 10 cm erosion -> 400 kg/ha or 3.7% of max.;
  • #13 Could you identify where greatest water holding capacity exists and where water for crops would be limited?
  • #18 At 50 years is $4536/A total loss or >$90/A average
  • #20 Conservation Stewardship Program, Conservation Technical Assistance, Conservation Reserve Program, Conservation Security Program, Environmental Quality Incentive Program