rick cruse - corn/soy systems
TRANSCRIPT
Goals
Co$t of $oil Ero$ion
Rick CruseScott LeeTim SklenarIowa State University
The True Cost of American Food14-17th April 2016Fort Mason Center San Francisco
What does it cost?
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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: 5576What 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.1Where nutrient deficits are avoided by fertilization, response curves are generally convex, implying that reductions will become increasingly severe with further erosion. 1
Boone County. Tom Kaspar, USDA/ARS personal communication.
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/ha10 cm erosion -> 400 kg/ha or 3.7% of max.;
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4.8 T/A
1.6 T/A5.4 T/A
5.4 T/A
8.0 T/A
State Wide Average 5.7 T/A/YROne pound of soil for each pound of corn produced
Could you identify where greatest water holding capacity exists and where water for crops would be limited?12
Simplify, Simplify, Simplify, SimplifyAverage 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 corn5.7 tons soil loss/A cost producer next year $0.35/A
Nutrient Redistribution and LossNutrient value in eroded topsoil5.7 Tons/AMostly redistributed in fieldSediment Delivery Ratio = 0.35(5.7 Tons/A) X = 2 Tons/A(2 Tons/A) X ($2.10/Ton1) = $4.20
1Iowa Learning Farms. 2013. Cost of soil erosion. http://www.extension.iastate.edu/ilf/sites/www.extension.iastate.edu/files/ilf/Cost_of_Eroded_Soil.pdf
Cumulative cost ($/A)Years1Nutrient loss value $2.10/ton for exported soil
Cumulative cost ($/A)Years1Nutrient loss value $2.10/ton for exported soil$30/A/Yr Soil Conservation
Cumulative cost ($/A)Years$30/A/Yr for Soil Conservation1Nutrient loss value = $28.30/A for exported topsoil
At 50 years is $4536/A total loss or >$90/A average17
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.1Approximately $125/A for 24 million row crop acresApproximately $12.50/A/Yr
1Rundquist, Soren and Craig Cox. 2016. Fooling ourselves: voluntary programsfail to clean-up dirty water. Environmental Working Group. Washington DC.
Conservation Stewardship Program, Conservation Technical Assistance, Conservation Reserve Program, Conservation Security Program, Environmental Quality Incentive Program19
Farm Costs ~ $ 4.55/A/YROff Site Damage ~ $25.00/A/YRPublic Investment ~ $12.50/A/YR $40+/A/YR
Summary
Global Food $ecurity?????Weve 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, were really going to need this soil.1 Seth Watkins farmer Clarinda, IA.Kezar, Mitch. 2016. Theres no magic bullet to stop erosion. Commonsense practices help. Successful Farming. Available on line.http://www.agriculture.com/content/real-world-conservation
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ConclusionsIndustrial Ag - Soil conservation more expensive than soil erosion for the farmerSoil conservation is added expenseUnless farmer owns the land for extended time and erosion rates are highErosion cost to public is greater than cost to the farmer