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MEMORANDUM

TO: Air and Radiation Docket EPA-HQ-OAR-2015-0093

FROM: EPA Office of Transportation and Air Quality

DATE: April 15, 2015

SUBJECT: Supporting Documentation for Emissions Related to the Production and Transport 

of Carinata.

The document “Carinata data and calculations – for docket.xlsx” contains data and calculations

used in the analysis of greenhouse gases attributable to the production of carinata oil for biofuel. 

This memorandum provides additional explanation of these data points and calculations

including:

 Assumptions about fertilizer use and other inputs for growing carinata. 

Current literature and research suggests a range of fertilizer inputs that have been applied for 

growing carinata. Therefore, to capture the range of conceivable impacts, we used a range of 

fertilizer estimates that may be appropriate in a variety of conditions. The petitioner, 

Agrisoma Biosciences, Inc., recommended 60 lbs/acre of nitrogen based on application rates 

for their research plots. On these research plots, the carinata is grown in a continuous 

cropping system, whereas for commercial production carinata will likely be grown in fallow 

rotation which requires less fertilizer input as there is generally residual soil nutrient from the 

primary crop. As a low nitrogen estimate we assume 40 lbs/acre based on recommended rates 

for camelina, a Brassicaceae that is similar to carinata. As a high nitrogen estimate, we are 

assuming 80 lbs/acres. In recent trials, USDA has applied a range of 50 – 70 lbs/acre, 

however other studies have shown increases in yields at higher application rates.1These 

studies did not attempt to assess these yield tradeoffs against the economic costs and returns 
2

from varied nitrogen application or recommend an optimal application rate (or rates). 

Therefore, we believe 80 lbs/acre is a reasonable upper estimate.

As the upper bound for phosphorus and potassium inputs, we used 30 lbs/acre and 10 

lbs/acre, respectively. The phosphorus value is based on guidance from the petitioner: 30 

lbs/acre is the application rate used for the carinata continuous cropping system test plots. 

The petitioner did not recommend potassium fertilizer for carinata production, claiming that

the land expected to be used for carinata growth generally has sufficient levels of potassium

for carinata production. However, to capture regional variability in soil quality, we assume 

10 lbs/acre as a high estimate of the amount recommended for camelina production. 

According to the U.S. Department of Agriculture, sulfur can also be a beneficial fertilizer 

component for oilseeds such as carinata and soybeans, dependent on local soil characteristics, 

at application rates of up to 10-20 lbs/acre.2There are multiple options for sulfur application 

as part of a liquid or dry granular mixture that also contain phosphorus and nitrogen. The 

emissions for fertilizer rates provided in Table 3 of the preamble capture the likely range of 

impacts associated with the variety of application options, including ones containing sulfur.

 Carinata yield

We project 1,865 pounds of carinata seed per acre as the 2022 average yield. This is based on 

the average yield from 15 test plots across the U.S. and Canada between 2009 and 2012.3 As 

research plots produce higher yields than commercial production, we believe this is a 

reasonable approximation of the average 2022 commercial yield. Other studies show a range 

of yields similar to those of the petitioner based on experiments varying factors such as

nitrogen application, water stress, and seed spacing. One such study showed a yield ranging 

from 552 to 2,434 lbs of seed/acre.4 We believe a projected yield of 1,865 lbs of seed per 

acre in 2022 is reasonable for the purposes of evaluating the GHG emissions associated with 

growing carinata as a biofuel feedstock. 

 Calculations of the nitrous oxide (N2O) emissions from fertilizer and crop residues, for 

carinata and soybeans.
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Equations for direct and indirect emissions from these sources are from the 

Intergovernmental Panel on Climate Change.5 To calculate the amount of crop residues from 

carinata, and the nitrogen content of these crop residues, we used data on canola as a 

substitute for carinata,

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because data on carinata were not available, and both canola and 

carinata are oilseed plants in the Brassicaceae family. 

 Net returns for growing carinata

Planting, harvesting, and price per pound of carinata seed assumptions were based on 

information from the petitioner. The petitioner also provided information on the amount of 

seed that would need to be planted to achieve the current technically feasible –and 2022 

projected average –yield of 1,865 pounds of seed per acre. 

 Energy inputs and greenhouse gas emissions from extracting oil from carinata seeds

Estimates of the energy requirements for the crushing of carinata seeds were based on 

information submitted by the petitioner. The petitioner based their data on a survey of 10 

canola crushing plants in the US and Canada, with the results normalized for the oil content 

of carinata.7EPA then used emissions factors from the RFS2 Final Rule (2010) to produce 

estimates of associated emissions.

 

1

In these studies, nitrogen rates were tested at rates up to 134 and 178 lbs/acre (150kg/ha and 

200kg/ha respectively). Coinciding with positive yield impacts, there were also findings of 

diminishing nitrogen fertilizer use efficiency, and declining oil content at the expense of higher 

protein content with greater N application.

Pan, X. et al (2011) Water-stress and N-nutrition effects on photosynthesis and growth of 

Brassica carinata Photosynthetica 49 (2): 309-315.

Pan, X. et al (2012) The effect of cultivar, seeding rate and applied nitrogen on Brassica carinata 

seed yield and quality in contrasting environments. Can. J. Plant sci. 92: 961-971

Johnson, E. N. et al (2013) Effects of nitrogen fertilizer application on seed yield, N uptake, N 

use efficiency, and seed quality of Brassica carinata. Can. J. Plant sci. 93: 1073-1081

2 Telephone call with USDA, March 26, 2015.

3 Agrisoma Biosciences Inc. petition to the EPA, August 2013.
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4 Pan, X. et al (2012) The effect of cultivar, seeding rate and applied nitrogen on Brassica 

carinata seed yield and quality in contrasting environments. Can. J. Plant Science. 92: 961-971.

5

Intergovernmental Panel on Climate Change (2006). “N2O emissions from managed soils, and 

CO2 emissions from lime and urea application.” 2006 IPCC Guidelines for National Greenhouse 

Gas Inventories, Volume 4: Agriculture, Forestry, and Other Land Use. Eggleston, H.S., 

Buendia, L., Miwa, K., Ngara, T., and Tanube, K (eds). Published: IGES, Japan.

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Janzen, H. H. et al (2003). “The fate of nitrogen in agroecosystems: An illustration using 

Canadian estimates.” Nutrient Cycling in Agroecosystems. 67: 85-102.

7 Agrisoma Biosciences Inc. petition to the EPA, August 2013.