1

Comparison of production-phase life cycle environmental impact metrics derived at the farm- and national-scale for United States agricultural commodities

Supporting Information

Authorship: Christine Costello,1* Xiaobo Xue2 and Robert W. Howarth3

1. Department of Bioengineering, University of Missouri, Columbia, Missouri 65211. *Corresponding author phone: (607) 745-0259; email: costelloc@missouri.edu 2. Department of Environmental Health Sciences, University at Albany, State University of New York, School of Public Health, NY 12144 3. Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853.

Number of Pages: 25 (including cover page)

Number of Figures: 6 Number of Tables: 17

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1. Equations for deriving impact metrics   The equations in Table S1 describe the calculations and data used to create links between crops and livestock used to estimate nitrogen inputs and outputs, greenhouse gas emissions and land use associated with these commodities. First, crop production estimates (by weight and acreage) from NANI are divided into two categories: exports (USDAa) and domestic fraction. The domestic crop fraction is subsequently allocated to humans and livestock based on estimates included in the NANI calculations, Table S2. For corn, corn destined for ethanol production is subtracted from the domestic fraction of corn available, see details below. In order to establish specific relationships between individual crops and individual livestock categories additional steps were taken using data from a Canadian study (Statistics Canada; Tables S5, S7 and S8), which included detailed estimates of the amount of whole grain and forage equivalents fed to specific livestock types. Using this data the ratio of crops to forage was calculated and applied to the N requirements per animal (as estimated in NANI; Table S5) resulting in a division of the total nutrition requirement into the two categories. Next, specific crop and forage amounts were estimated using U.S. crop production data by allocating according to the total N content in each crop and forage source available for animal consumption in the U.S. See the main text for more detail and an example calculation. N inputs and outputs, greenhouse gas emissions and land use estimates per unit of crop were estimated using publically available national datasets. The N inputs and outputs, GHGs and land use associated with livestock production were estimated per kilogram of edible output, e.g., beef, milk. Since a breeding livestock population exists to support meat, milk and egg production all of the N inputs and outputs, GHGs and land use associated with the entire population in 2002 were normalized by the commodity output, Table S12. In summary, these calculations create clear links between crops and livestock and between production and consumption. The laws of mass conservation were observed and all of the crops, animals and animal-sourced commodities were accounted for in this analysis. Ethanol and Distiller’s Grains In 2002, 9.4% of U.S. corn production, 165.2 million tons, was processed for ethanol production (USDA). Of this 40% was wet milled and 60% was dry milled. Wet milling produces 0.22 kg corn gluten feed (CGF) per kg of corn processed and 0.04 kg corn gluten meal (CGM) per kg of corn processed (O’Brien and Woolverton 2009). CGF contains 0.21 kg protein/kg CGF and CGM contains 0.60 kg protein/kg CGM (Obrien and Woolverton 2009). Protein was converted to nitrogen using the values for DDGS reported by Liu of 6.25 N:protein (2011). Dry milling produces 2.2 kg dried distillers grains with solubles (DDGS) per kg corn (O’Brien and Woolverton 2009), which are 4.38% nitrogen by weight (dry weight) (Liu 2011). It was assumed that all of the ethanol production feed co-products were utilized as animal feed. The Renewable Fuels Association provided data regarding the amount of this feed source used by specific livestock sectors in 2003, it was assumed that these percentages applied to 2002 as well: 46% to dairy cattle, 39% to beef cattle, 11% to swine and 4% to poultry (RFA, 2003). These percentages were used to allocate each co-product to each livestock type associated with each commodity, Table S3. The amount of N contained within each portion was subtracted from the total animal N requirement and the allocation of crops described in the main text and the equations below was applied to fulfill the remaining feed needs. Environmental impacts were allocated to ethanol and feed for livestock production using weight-based allocation factors (Shapouri et al 2002). For wet milling the allocation factor for ethanol is 49% and 51% for feed co-products; for dry milling the allocation factor for ethanol is 48% and 52% for feed co-products (Shapouri et al 2002).

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            Figure S1. Greenhouse gas data flow diagram. Shaded boxes are modeling outputs, un-shaded boxes are modeling inputs.                   Figure S2. Land use data flow diagram. Shaded boxes are modeling outputs, un-shaded boxes are modeling inputs.

GHG estimates of major agricultural commodities, based on USDA & EPA datasets (USDA, 2011; EPA, 2013)

N2O estimates of non-major agricultural commodities allocated to individual crops using fertilizer application data (USDAc)

GHG estimates of cropland and noncropland pasture, based on USDA datasets and NANI production estimates

GHGs for crop-sourced commodities, Table 1, Figures 1c-1f

GHG estimates for enteric fermentation and manure management

GHGs for animal-sourced commodities, based on feed consumption, Table 1, Figures 1c-1f

Planted acreage for each crop, based on USDA datasets and NANI

The acreage for pasture and rangelands based on Costello et al 2011

Land use for crop-sourced commodities, Table 1, Figures 1g & 1h

Land use for animal-sourced commodities, Table 1, Figures 1g and 1h

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Table S1. Calculations for estimating environmental metrics for agricultural commodities

Equation

Variable description

Data source

𝐶! = 𝐶𝑒! + 𝐶𝑑!× ℎ! + 𝑙! Note for corn i=1: 𝐶! = 𝐶!! + 𝐶!"! + 𝐶!!

Ci = kg total crop production (Table S2) Hong et al., 2011 Cei = kg exported crops (Table S2) USDAa Cdi = kg domestically available crops (Table S2)

USDAa

Ceth = corn entering ethanol production, kg hi = % allocated to humans (Table S2) Hong et al., 2011 li = % allocated to animals (Table S2) Hong et al., 2011 i = crops 1 through 15 (Table S2)

𝐴! = 𝐴!×(𝑐! + 𝑓!  ) 𝑎!" = 𝐴!𝑐!×𝑟!" 𝑎!" = 𝐴!𝑓!×𝑟!"

𝑁!",! = 𝐿!× 𝑎!" + 𝑎!" 𝐶𝑑!" = 𝑁!"×𝑟! 𝑛!" = 𝑁!"/𝑃!

𝑐!" = 𝑛!"×𝑟! = 𝐶𝑑!" 𝑃!

Aj = animal N requirement, kg N / animal (Table S5, “NANI Animal N Requirement”)

Hong et al., 2011

cj = portion of animal N requirement met by crops for animal, j. (Table S8)

Derived from Statistics Canada, 2003

fj = portion of animal N requirement met by forages for animal, j. (Table S8)

Derived from Statistics Canada, 2003

aji = N requirement met by crop, i, for individual animal, j (Table S3), kg N / animal

ajf = N requirement met by forage, f, individual animal, j, kg N / animal

rji = allocation factor for individual crop i (Table S9)

Derived from Hong et al., 2011

rjf = allocation factor for individual forage f (Table S9)

Derived from Hong et al., 2011

Nji = total N from each crop, i, per livestock category, j, kg N (Table S11, “Crop N Available for Livestock”)

Lj = livestock population (Table S3) Hong et al., 2011 Nki/f = total N from each crop, i, or forage, f, allocated to animal-sourced commodity, k, kg N (sum Nji to Nki;Table S3)

Cdki = crops, i, consumed by livestock, j, to produce animal-sourced commodities, k, kg crops.

nki = kg N in crop required to produce kg animal-sourced commodity

cki = kg crop per kg animal-sourced commodity

ri = kg N/kg crop Hong et al., 2011 Pk = total kg of animal-sourced commodity, k j = animal type, j, (Table S3)

𝑋! = 𝑥!×𝐶𝑎! 𝑦!,! = 𝑋! 𝐶𝑤!

Xi = total fixation per crop

xi = fixation rate per crop, kg N fix/km2 Hong et al., 2013 yXi = kg N fixation per kg crop i

𝑀! = 𝐿!×𝑚! 𝑦!,! = 𝑀! 𝑃!

Mj = total manure for all livestock, j, kg Hong et al., 2011; Boyer et al. 2002.

mj = manure excretion rate, kg N excreted as manure per animal, j, per year

Mk = total manure for all livestock that contribute to the production of an animal-sourced commodity, k (Table S3)

𝐵! = 𝐿!×𝑏! 𝑏! = 𝐵! 𝑃!

Bj = total NH3-N for all livestock, j, kg bj = ammonia (NH3) excretion rate, kg NH3-N emitted per livestock per year

Hong et al., 2011; Boyer et al., 2002

Bk = NH3-N per kg animal-sourced commodity

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𝑦!,! = 𝐺! 𝐶! 𝑔𝑐! =   𝑐!"×𝑦!,! 𝑔𝑒! = 𝐺𝑒!/𝑃! 𝑔𝑚! = 𝐺𝑚!/𝑃!

𝑦!,! = 𝑔𝑐! + 𝑔𝑒! + 𝑔𝑚!  

yG,i = kg CO2e per kg crop Gi = total GHG emissions due to cultivation of crop i, kg CO2e

Derived from USDA, 2011; EPA, 2013

gck = GHG emissions due to feed crops per animal-sourced commodity, k, kg CO2e per kg commodity

Derived using EPA, 2013

Gek = total methane emissions from enteric fermentation for total animal-sourced commodity (kg CO2e)

EPA, 2013

Gmk = nitrous oxide and methane emissions from manure management

EPA, 2013

gek = methane emissions from enteric fermentation per animal-sourced commodity, k, kg CO2e per kg commodity

gmk = nitrous oxide and methane emissions from manure management per animal-sourced commodity, k, kg CO2e per kg commodity

yG,k = kg CO2e per kg animal-sourced commodity

𝑦!,! = 𝑇! 𝐶! 𝑦!,!" = 𝑦!,!×𝑐!" 𝑦!,! = 𝑇! 𝑃!

yT,i = land occupied per kg crop, i (km2/kg)

Ti = land occupied for each crop, i, km2 USDA, 2002; Costello et al., 2011

Tk = land directly occupied for livestock farming operations

USDA, 2002; Costello et al., 2011

yT,k = land directly occupied per kg animal-sourced commodity

yT,ki = land area occupied by crops estimated to be fed to livestock to produce one kg of animal sourced commodities, km2 per kg animal-sourced commodity

𝑧!,!" = 𝑐!"×𝑦!,! zF,ki = fertilizer applied to produce crops fed to livestock in order to produce 1 kg animal-sourced commodity, kg N / kg product

yF = kg of fertilizer applied per kg of crop, i, produced, kg N / kg product

USDAb, 2012; USDAc, 2012

𝑧!,!" = 𝑐!"×𝑦!" zX,ki = N fixation resulting from the production of crops fed to livestock in order to produce 1 kg animal-sourced commodity, kg N / kg product

                       

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2. Data Tables Table S2. Crop production, exports and allocation to humans and animals

i Crop Production (kg)

Exported (kg)

Domestically available

production (kg)

Allocated to humans (kg, %)1

Allocated to animals (kg, %)1

1 corn for grain2 2.19E+11 3.28E+10 1.65E+112 6.61E+09 (4%) 1.59E+11 (96%)

2 corn for silage 8.80E+10 0.00E+00 8.80E+10 0.00E+00 (0%) 8.80E+10 (100%)

3 wheat 4.11E+10 2.42E+10 1.69E+10 1.03E+10 (61%) 6.60E+09 (39%)

4 oats 1.59E+09 3.36E+07 1.56E+09 9.34E+07 (6%) 1.46E+09 (94%)

5 barley 4.67E+09 4.71E+08 4.20E+09 1.26E+08 (3%) 4.07E+09 (97%)

6 sorghum for grain 8.44E+09 5.43E+09 3.01E+09 0.00E+00 (0%) 3.01E+09 (100%)

7 sorghum for silage 3.54E+09 0.00E+00 3.54E+09 0.00E+00 (0%) 3.54E+09 (100%)

8 potatoes 2.04E+10 8.98E+08 1.95E+10 1.95E+10 (100%) 0.00E+00 (0%)

9 rye 1.84E+08 4.25E+06 1.80E+08 3.05E+07 (17%) 1.49E+08 (83%)

10 alfalfa hay 6.21E+10 1.07E+09 6.10E+10 0.00E+00 (0%) 6.10E+10 (100%)

11 other hay 7.56E+10 1.64E+09 7.39E+10 0.00E+00 (0%) 7.39E+10 (100%)

12 soybeans 7.36E+10 2.77E+10 4.60E+10 9.19E+08 (2%) 4.50E+10 (98%)

13 cropland pasture 2.74E+10 0.00E+00 2.74E+10 0.00E+00 (0%) 2.74E+10 (100%)

14 noncropland pasture 9.62E+10 0.00E+00 9.62E+10 0.00E+00 (0%) 9.62E+10 (100%)

15 rice 9.51E+09 3.82E+09 5.69E+09 5.69E+09 (100%) 0.00E+00 (0%)

Note:  1. Percentages in parenthesis indicate percent of crop distribution to humans or livestock, distribution adapted from NANI model. 2. The amount of corn used for ethanol production, 2.06E+10 kg, is subtracted from the estimates presented in this table. Environmental impacts associated with this corn were allocated to ethanol and animals as described in the manuscript and section 1 of the Supporting Information.

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Table S3. Livestock population estimates and livestock to animal-sourced commodity key j Livestock type Number of

animals Commodity

category 1 fattened cattle 1.126E+07 beef

2 milk cows 9.072E+06 milk

3 hogs for breeding 6.166E+06 pork

4 hogs for slaughter 6.177E+07 pork 5 chicken layers 3.335E+08 eggs 6 breeding turkeys 4.649E+06 turkey

7 chicken pullets 8.521E+07 chicken

8 chicken broilers 1.409E+09 chicken 9 slaughter turkeys 1.128E+08 turkey

10 beef breeding herd 3.492E+07 beef 11 beef calves 1.133E+07 beef 12 dairy calves 2.423E+06 milk 13 beef heifers 2.029E+06 beef

14 dairy heifers 7.457E+05 milk 15 beef stockers 2.628E+07 beef 16 dairy stockers 0.000E+00 milk 17 sheep1 6.316E+06 NA 18 horses1 3.630E+06 NA 19 goats1 5.902E+05 NA

Note: 1. It is assumed that horse meat is not eaten in the U.S. Data regarding the mix of milk, fiber and meat produced from sheep and goats were not sufficient to allocate inputs to commodities.   Table S4. Nitrogen content and nutritional information for crops

Crop Fertilizer applied

(kg/km2)1

% Dry Matter1

% N in Dry

Matter2

kcal/kg

crop3

protein/kg crop3

USDA code3 USDA description3

corn for grain 14705 0.867 0.014 3620 81.2 20020 Cornmeal, whole-grain, yellow

corn for silage -- 0.284 0.012 0 0 NA NA wheat 7135 0.885 0.022 3400 132.1 20080 wheat flour, whole-grain oats 6043 0.894 0.020 3890 168.9 20033 oat bran, raw barley 6741 0.889 0.021 3450 105 20004 barley, hulled sorghum for grain 9104 0.894 0.020 3390 113 whole kernel4 sorghum for silage -- 0.580 0.013 0 0 NA NA potatoes 23674 0.223 0.016 770 20.2 11352 potato, flesh and skin rye 4493 0.881 0.022 3380 103.4 20062 rye alfalfa hay 2246 0.904 0.028 0 0 NA NA other hay 2246 0.867 0.013 0 0 NA NA soybeans 452 0.906 0.065 1470 129.5 11450 soybeans, green, raw cropland pasture 0 1.000 0.025 0 0 NA NA noncropland pasture 0 1.000 0.020 0 0 NA NA

rice 17966 0.889 0.014 3580 65 20452 Rice, white, short-grain, raw, unenriched

soybean meal -- -- 7.00 -- -- -- canola meal -- -- 5.76 -- -- -- Notes: 1. Area-weighted average using available data over 1999-2008, data was not recorded for all crops each year. Fertilization rates for alfalfa hay and other hay are based on Koenig et al., 1999. 2. Values from Hong et al., 2011, updated % N in corn dry matter in Hong et al., 2013 3. USDA, 2012c. 4. FAO 1995.

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Table S5. Canadian and NANI animal requirement, manure N content and ammonia N assumptions per animal per year

Canadian descriptor NANI descriptor Approximate N requirement – Canadian data

(kg)

% grain % forage NANI Animal N Requirement

N from grain (kg)

N from forage

(kg)

N manure per

animal (kg)

N ammonia per animal

(kg)

Steers & Heifers Slaughter fattened cattle 77.9 47% 53% 50.3 23.9 26.4 48 19.2

Slaughter Calves fattened cattle 19.3 76% 24% 50.3 38.3 12.0 48 19.2

Dairy Cows milk cows 105.3 60% 40% 130.8 78.4 52.4 104 26 Sow and Bred Gilts hogs for breeding 25.2 100% 0% 13.8 13.8 0 9.1 4.7 Boars hogs for slaughter 19.8 100% 0% 24 24.0 0 5.8 3 Layers chicken layers 0.7 100% 0% 0.8 0.8 0 0.7 0.3 Turkeys breeding turkeys 0.5 100% 0% 2.1 2.1 0 1.7 0.8 Chickens chicken pullets 0.1 100% 0% 0.4 0.4 0 0.4 0.2 Chickens chicken broilers 0.1 100% 0% 0.8 0.8 0 0.7 0.3 Turkeys slaughter turkeys 0.5 100% 0% 2.1 2.1 0 1.6 0.7 Beef cattle average beef breeding herd 75.1 19% 81% 60.9 11.7 49.2 59.8 4.8 Bull calves < 1yr beef calves 19.3 76% 24% 19.9 15.2 4.7 9.8 0.8 Other dairy calves dairy calves 39.2 40% 60% 10.6 4.2 6.4 6.7 0.5 Avg of >1 yr and <1 yr dairy heifer beef heifers 47.0 27% 73% 40.5 11.1 29.4 28.2 2.3

dairy heifer >1 yr dairy heifers 54.8 15% 85% 43.5 6.7 36.8 34.2 2.7

Average of Beef Rep Heifers >1 and <1 yr beef stockers 46.6 12% 88% 37.6 4.3 33.3 26.6 10.6

dairy stockers 76.8 50% 50% 37.6 18.6 19.0 18.6 7.4

Slaughter lamb sheep 3.8 16% 84% 14.5 2.4 12.1 8.4 5.6 Horses horses 74.7 10% 90% 44.8 4.6 40.2 40 9.3 Slaughter lamb goats 3.8 16% 84% 5.97 1.0 5.0 5 5.26

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Table S6. Comparison of total fertilizer estimates in this study against USDA data

crop Estimated in NANI (kg N) USDA reported1 (kg N)

2002 2007 2002 2007

corn for grain 4,060,017,035 5,132,312,915 4,281,660,565 5,183,649,376

corn for silage 0 0 NA NA

wheat 1,314,408,162 1,470,710,563 1,588,718,744 1,532,233,776

oats 48,803,725 36,878,509 NA NA

barley 109,445,981 95,960,304 NA NA

sorghum for grain 248,875,706 249,410,198 NA NA sorghum for silage 0 0 NA NA

potatoes 121,215,032 108,364,975 NA NA

rye 5,188,472 4,861,109 NA NA

alfalfa hay 205,788,927 184,040,054 NA NA

other hay 345,379,521 344,301,795 NA NA

soybeans 132,543,081 117,011,329 140,613,520 109,769,264

cropland pasture 0 0 NA NA noncropland pasture 0 0 NA NA

rice 232,484,635 200,578,097 NA NA

other 3,725,778,249 2,507,791,064 4,422,802,510 5,245,337,888

sum: 10,549,928,527 10,452,220,911 10,894,644,811 12,471,058,448 Note: 1. USDAb, 2012.

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Table S7. Kilograms of feed by crop per livestock category, national Canadian average1

Livestock Type W

heat

Oat

s

Bar

ley

Oth

er S

mal

l G

rain

s

Gra

in C

orn

Dry

Pea

s

Soyb

ean

Mea

l

Can

ola

Mea

l

Mill

Scr

een

Tota

l Gra

in

Non

-gra

in

port

ion2

Com

plet

e G

rain

-bas

ed

Rat

ion

Past

ure

Dry

Hay

Sila

ge

Oth

er

Rou

ghag

es

Tota

l R

ough

ages

kg per animal

Beef Cattle 15 160 351 9 74 9 21 14 40 693 16 709 1525 1037 629 271 3461

Bulls on Beef farms 13 234 229 10 11 11 7 27 27 569 9 578 1782 1977 689 291 4739

Beef Cows 6 41 90 2 2 2 2 6 14 165 3 168 2043 1523 470 479 4515 Beef Rep Heifers > 1

year 4 124 109 5 11 5 3 11 21 293 4 297 1304 1403 330 212 3250 Beef Rep Heifers < 1

year 4 89 42 3 14 4 2 8 11 177 3 180 524 528 129 100 1281

Bull Calves < 1 year 10 379 242 10 55 11 14 32 27 779 15 794 575 481 267 109 1431

Slaughter Calves 11 83 81 1 477 6 54 25 4 743 28 771 162 42 18 7 229 Steers & Heifers

Slaughter 35 376 962 24 171 23 58 26 100 1774 43 1817 1206 375 1181 36 2798

Dairy Cattle 54 29 448 38 847 1 165 55 121 1757 91 1849 315 1143 1953 20 3432

Bulls on Dairy Farms 7 11 131 18 180 0 44 7 6 404 13 417 556 1523 1270 43 3392

Dairy Cows 91 20 748 52 1443 3 266 95 218 2938 162 3099 326 1027 2976 0 4328 Dairy Heifers > 1

year 8 11 111 18 186 0 43 5 6 387 11 398 542 1459 1335 29 3365 Other Dairy calves <

1 year 23 64 157 27 263 0 77 21 35 666 25 691 59 1063 425 54 1602

Sheep and Lambs 1 6 26 1 5 1 2 1 1 43 1 43 171 205 34 3 413

Rams & Ewes 2 6 32 1 4 1 2 1 2 49 1 50 257 371 74 5 707

Breeding Lambs 0 12 58 0 5 0 2 0 1 80 1 81 151 187 13 4 355

Slaughter Lambs 0 4 14 1 6 0 2 1 0 30 1 31 97 57 1 0 155

Hogs 29 1 73 0 129 7 37 13 4 292 15 307 0 0 0 0 0

Boars 66 35 381 3 228 20 55 45 15 848 39 888 0 0 0 0 0

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Notes: 1. Statistics Canada, 2003. 2. Non-grain portion is the quantity of all non-grain components of the complete grain-based rations including supplements, minerals, fats, sweeteners and animal by-products.

Sows & Bred Gilts 100 13 370 0 358 19 105 52 15 1032 50 1082 0 0 0 0 0

Weaner Pigs 1 0 3 0 13 1 5 0 0 23 4 27 0 0 0 0 0

Feeder Pigs 28 0 63 0 120 7 32 12 3 266 11 277 0 0 0 0 0

Layers 11.3 0 0 0 10.2 0 3.4 2.1 1.7 28.7 6.7 35.4 0 0 0 0 0

Chickens 0.7 0 0.3 0 1.4 0 0.5 0.1 0.1 3.1 0.8 3.9 0 0 0 0 0

Turkeys 5.3 0 0 0 7 0 3.7 0.6 0.6 17.2 4.3 21.5 0 0 0 0 0

Other Poultry 0.9 0 0 0 1.4 0 0.7 0.1 0.2 3.3 0.8 4.1 0 0 0 0 0

Horses 0 193 77 10 24 2 26 4 2 336 19 356 1515 1756 50 62 3383

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Table S8. Kilograms of N in feed by crop per livestock category, national Canadian average1

Livestock Type W

heat

Oat

s

Bar

ley

Oth

er S

mal

l G

rain

s

Gra

in C

orn

Dry

Pea

s

Soyb

ean

Mea

l

Can

ola

Mea

l

Mill

Scr

een

Tota

l Gra

in

Past

ure

Dry

Hay

Sila

ge

Oth

er

Rou

ghag

es

Tota

l R

ough

ages

% g

rain

% ro

ugha

ge

(fora

ges)

kg N per animal, except where noted

Beef Cattle 0.29 2.93 6.59 0.16 0.90 0.53 1.47 0.81 0.78 14.5 34.3 18.8 3.4 4.2 60.7 19% 81%

Bulls on Beef farms 0.25 4.29 4.30 0.18 0.13 0.65 0.49 1.56 0.52 12.4 40.1 35.8 3.8 4.5 84.1 13% 87%

Beef Cows 0.11 0.75 1.69 0.04 0.02 0.12 0.14 0.35 0.27 3.5 46.0 27.5 2.6 7.4 83.4 4% 96% Beef Rep Heifers > 1

year 0.08 2.27 2.05 0.09 0.13 0.30 0.21 0.63 0.41 6.2 29.3 25.4 1.8 3.3 59.8 9% 91% Beef Rep Heifers < 1

year 0.08 1.63 0.79 0.05 0.17 0.24 0.14 0.46 0.21 3.8 11.8 9.6 0.7 1.5 23.6 14% 86%

Bull Calves < 1 year 0.19 6.94 4.54 0.18 0.67 0.65 0.98 1.84 0.52 16.5 12.9 8.7 1.5 1.7 24.8 40% 60%

Slaughter Calves 0.21 1.52 1.52 0.02 5.79 0.36 3.78 1.44 0.08 14.7 3.6 0.8 0.1 0.1 4.6 76% 24% Steers & Heifers

Slaughter 0.67 6.89 18.1 0.44 2.08 1.36 4.06 1.50 1.94 37.0 27.1 6.8 6.4 0.6 40.9 47% 53%

Dairy Cattle 1.03 0.53 8.41 0.70 10.3 0.06 11.6 3.17 2.35 38.1 7.1 20.7 10.7 0.3 38.7 50% 50% Bulls on Dairy Farms

farms 0.13 0.20 2.46 0.33 2.18 0 3.08 0.40 0.12 8.9 12.5 27.5 6.9 0.7 47.7 16% 84%

Dairy Cows 1.73 0.37 14.0 0.95 17.5 0.18 18.6 5.47 4.24 63.1 7.3 18.6 16.3 0 42.2 60% 40%

Dairy Heifers > 1 year 0.15 0.20 2.08 0.33 2.26 0 3.01 0.29 0.12 8.4 12.2 26.4 7.3 0.4 46.3 15% 85% Other Dairy calves < 1

year 0.44 1.17 2.95 0.49 3.19 0 5.39 1.21 0.68 15.5 1.3 19.2 2.3 0.8 23.7 40% 60%

Sheep and Lambs 0.02 0.11 0.49 0.02 0.06 0.06 0.14 0.06 0.02 1.0 3.8 3.7 0.2 0.0 7.8 11% 89%

Rams & Ewes 0.04 0.11 0.60 0.02 0.05 0.06 0.14 0.06 0.04 1.1 5.8 6.7 0.4 0.1 13.0 8% 92%

Breeding Lambs 0.00 0.22 1.09 0.00 0.06 0 0.14 0 0.02 1.5 3.4 3.4 0.1 0.1 6.9 18% 82%

Slaughter Lambs 0 0.07 0.26 0.02 0.07 0 0.14 0.06 0 0.6 2.2 1.0 0.0 0 3.2 16% 84%

Hogs 0.55 0.02 1.37 0 1.57 0.41 2.59 0.75 0.08 7.3 0 0 0 0 0 100% 0%

Boars 1.26 0.64 7.15 0.05 2.77 1.18 3.85 2.59 0.29 19.8 0 0 0 0 0 100% 0%

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Sows & Bred Gilts 1.90 0.24 6.94 0 4.35 1.12 7.35 3.00 0.29 25.2 0 0 0 0 0 100% 0%

Weaner Pigs 0.02 0 0.06 0 0.16 0.06 0.35 0 0 0.6 0 0 0 0 0 100% 0%

Feeder Pigs 0.53 0 1.18 0 1.46 0.41 2.24 0.69 0.06 6.6 0 0 0 0 0 100% 0%

Layers 0.22 0 0 0 0.12 0 0.24 0.12 0.03 0.7 0 0 0 0 0 100% 0%

Chickens 0.01 0 0.01 0 0.02 0 0.04 0.01 0.00 0.1 0 0 0 0 0 100% 0%

Turkeys 0.10 0 0 0 0.08 0 0.26 0.03 0.01 0.5 0 0 0 0 0 100% 0%

Other Poultry 0.02 0 0 0 0.02 0 0.05 0.01 0.00 0.1 0 0 0 0 0 100% 0%

Horses 0 3.53 1.44 0.18 0.29 0.12 1.82 0.23 0.04 7.7 34.1 31.8 0.3 1.0 67.1 10% 90%

Aquaculture2,3 11.3 0 0 0 0 0 16.9 0 0 28.1 0 0 0 0 0 100% 0% Note: 1. Statistics Canada, 2003.  

14

Table S9. Crop and forage allocation assumptions, based on N content in U.S. biomass allocated to livestock

Crop Crop N

available for livestock

N allocation

across grain1

N allocation across forages

corn for grain 1.92E+09 36.8% --

corn for silage 3.12E+08 6.0% --

wheat 1.26E+08 2.4% --

oats 2.68E+07 0.5% --

barley 7.64E+07 1.5% --

sorghum for grain 5.28E+07 1.0% --

sorghum for silage 2.61E+07 0.5% --

potatoes -- -- --

rye 2.85E+06 0.1% --

alfalfa hay 1.54E+09 -- 31.0%

other hay 8.12E+08 -- 16.4%

soybeans 2.67E+09 51.2% --

cropland pasture 6.85E+08 -- 13.8%

noncropland pasture 1.92E+09 -- 38.8%

rice -- -- --

all 1.04E+10 -- -- grains & oilseed (incl. silage) 5.45E+09 -- --

hay and pasture 4.96E+09 -- --

corn gluten feed 6.74E+07 (2) --

corn gluten meal 3.85E+07 (2) --

distiller’s grains 1.53E+08 (2) -- Note: 1. Corn and sorghum silage treated as grains (Adesogan and Newman, 2010). 2. The N content available from ethanol coproducts for animal consumption is calculated directly; see Section 1 in the S.I. for more details. Likewise, the N content from these feeds was directly subtracted from each animal’s annual N requirement before fulfilling the remaining N requirement per animal with grains and forages available to animals; see Section 1 and the main text for more detail.  

15

Table S10. Estimated annual per crop/forage kg N consumption per animal used in this analysis

Livestock Type

Cor

n - g

rain

Cor

n - s

ilage

Whe

at

Oat

s

Bar

ley

Sorg

hum

- gr

ain

Sorg

hum

- si

lage

Rye

Alfa

lfa h

ay

Oth

er h

ay

Soyb

eans

Cro

plan

d pa

stur

e

Non

crop

land

pa

stur

e

Cor

n gl

uten

feed

Cor

n gl

uten

mea

l

Dis

tille

rs g

rain

s

kg N crop or feed/animal

fattened cattle 8.58 1.40 0.56 0.12 0.34 0.24 0.11 0.01 8.00 4.22 12.0 3.57 10.0 0.31 0.17 0.70

milk cows 26.7 4.35 1.75 0.37 1.07 0.74 0.35 0.04 15.0 7.94 37.2 6.70 18.8 2.53 1.45 5.75

hogs for breeding 4.92 0.80 0.32 0.07 0.20 0.14 0.06 0.01 0.00 0.00 6.86 0.00 0.00 0.11 0.06 0.25

hogs for slaughter 8.68 1.41 0.57 0.12 0.35 0.24 0.11 0.01 0.00 0.00 12.1 0.00 0.00 0.11 0.06 0.25

chicken layers 0.29 0.05 0.02 0.00 0.01 0.01 0.00 0.00 0.00 0.00 0.41 0.00 0.00 0.00 0.00 0.00

breeding turkeys 0.77 0.13 0.05 0.01 0.03 0.02 0.01 0.00 0.00 0.00 1.08 0.00 0.00 0.00 0.00 0.00

chicken pullets 0.15 0.02 0.01 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.20 0.00 0.00 0.00 0.00 0.00

chicken broilers 0.29 0.05 0.02 0.00 0.01 0.01 0.00 0.00 0.00 0.00 0.41 0.00 0.00 0.00 0.00 0.00

slaughter turkeys 0.77 0.13 0.05 0.01 0.03 0.02 0.01 0.00 0.00 0.00 1.08 0.00 0.00 0.00 0.00 0.00

beef breeding herd 4.23 0.69 0.28 0.06 0.17 0.12 0.06 0.01 15.0 7.89 5.89 6.66 18.8 0.31 0.17 0.70

beef calves 5.25 0.85 0.34 0.07 0.21 0.14 0.07 0.01 1.39 0.73 7.30 0.62 1.73 0.31 0.17 0.70

dairy calves 0.13 0.02 0.01 0.00 0.01 0.00 0.00 0.00 0.16 0.09 0.18 0.07 0.20 2.53 1.45 5.75

beef heifers 3.98 0.65 0.26 0.06 0.16 0.11 0.05 0.01 8.84 4.67 5.54 3.94 11.1 0.31 0.17 0.70

dairy heifers 1.92 0.31 0.13 0.03 0.08 0.05 0.03 0.00 8.86 4.68 2.67 3.95 11.1 2.53 1.45 5.75

beef stockers 1.55 0.25 0.10 0.02 0.06 0.04 0.02 0.00 9.99 5.27 2.16 4.45 12.5 0.31 0.17 0.70

dairy stockers 5.08 0.83 0.33 0.07 0.20 0.14 0.07 0.01 4.36 2.30 7.08 1.94 5.45 2.53 1.45 5.75

sheep 0.87 0.14 0.06 0.01 0.03 0.02 0.01 0.00 3.77 1.99 1.21 1.68 4.71 0.00 0.00 0.00

horses 1.69 0.28 0.11 0.02 0.07 0.05 0.02 0.00 12.5 6.58 2.35 5.56 15.6 0.00 0.00 0.00

goats 0.36 0.06 0.02 0.00 0.01 0.01 0.00 0.00 1.55 0.82 0.50 0.69 1.94 0.00 0.00 0.00

16

Table S11. Crops estimated to be available by NANI compared to estimated using allocation methods

Crop

Crop N Available

for Livestock

(kg N)

Estimate of Crop N

Consumption – NANI

Estimate of Crop N

Consumption – Low

Estimate of Crop N

Consumption – High

Percent Difference - NANI:

Percent Difference - Low:

Percent Difference

- High:

(kg N) (kg N) (kg N) Available Available Available

corn for grain 1.93E+09 1.79E+09 8.15E+08 2.40E+09 7.2% 57.7% -24.5%

corn for silage 3.12E+08 2.91E+08 1.33E+08 3.90E+08 6.8% 57.5% -24.9%

wheat 1.26E+08 1.17E+08 5.35E+07 1.57E+08 6.6% 57.4% -25.3%

oats 2.68E+07 2.50E+07 1.14E+07 3.36E+07 6.7% 57.5% -25.0%

barley 7.64E+07 7.13E+07 3.25E+07 9.56E+07 6.6% 57.5% -25.2% sorghum for grain 5.28E+07 4.93E+07 2.25E+07 6.61E+07 6.7% 57.5% -25.1%

sorghum for silage 2.61E+07 2.34E+07 1.07E+07 3.14E+07 10.3% 59.1% -20.2%

potatoes 0.00E+00 0.00E+00 0.00E+00 0.00E+00 -- -- --

rye 2.85E+06 2.66E+06 1.21E+06 3.56E+06 6.8% 57.5% -24.9%

alfalfa hay 1.54E+09 1.12E+09 9.91E+08 1.55E+09 27.1% 35.6% -0.6%

other hay 8.14E+08 5.92E+08 5.23E+08 8.17E+08 27.3% 35.8% -0.3%

soybeans 2.67E+09 2.49E+09 1.13E+09 3.34E+09 6.8% 57.5% -25.0%

cropland pasture 6.85E+08 5.00E+08 4.42E+08 6.90E+08 27.1% 35.6% -0.6% noncropland pasture 1.92E+09 1.40E+09 1.24E+09 1.94E+09 27.1% 35.6% -0.6%

rice 0.00E+00 0.00E+00 0.00E+00 0.00E+00 -- -- --

corn gluten feed 6.74E+07 6.74E+07 6.74E+07 6.74E+07 0.0% 0.0% 0.0%

corn gluten meal 3.85E+07 3.85E+07 3.85E+07 3.85E+07 0.0% 0.0% 0.0%

distiller's grains 1.53E+08 1.53E+08 1.53E+08 1.53E+08 0.0% 0.0% 0.0%

 Table S12. Animal-sourced agricultural commodity production and nutritional information

Animal-sourced

commodity

Production, 2002 (1000

mt)1

kcal/kg edible

portion

g protein/kg

edible portion

USDA code2 USDA description2

Beef 12,187 2910 173.2 13001 beef, carcass, separable lean and fat, choice, raw

Milk3 76,900 640 32.8 01078 Milk, producer, fluid, 3.7% milkfat

Pork 8,805 4720 139.1 10001 pork, fresh, carcass, separable lean and fat, raw

Eggs 4,352 1430 125.6 01123 egg, whole, raw, fresh Chicken meat 14,852 2130 183.3 05001 chicken, broilers for fryers, meat and

skin,giblets, neck, raw Turkey meat 2,588 1570 203.7 05163 turkey, all classes, meat and skin and

giblets and neck raw Note: 1. USDAe. 2012. 2. USDAd, 2012 3. USDA 2003.      

17

Table S13. Results summary table.

food commodity kg N

fert/kg product

kg N fix/ kg product

kg N fert/ kcal

kg N fert/kg protein

kg N fix/kcal

kg N fix/ kg protein

kg manure-N/kg

product

kg N-NH3/kg product

kg manure-N/ kcal

kg N-NH3/kcal product

kg manure-N/kg protein

kg N-NH3/kg protein

corn for grain 1.86E-02 NA 5.13E-06 2.29E-01 NA NA NA NA NA NA NA NA corn for silage (1) (1) (2) (2) (2) (2) NA NA NA NA NA NA corn, wet-milled co-products corn gluten feed

3.32E-02 NA NA 1.58E-01 NA NA NA NA NA NA NA NA

corn, wet-milled co-product corn gluten meal)

3.32E-02 NA NA 5.53E-02 NA NA NA NA NA NA NA NA

corn, ethanol, dry-milled co-product, dried distillers grains

3.22E-02 NA NA 1.17E-01 NA NA NA NA NA NA NA NA

wheat 3.20E-02 NA 9.41E-06 2.42E-01 NA NA NA NA NA NA NA NA oats 3.07E-02 NA 7.89E-06 1.82E-01 NA NA NA NA NA NA NA NA barley 2.34E-02 NA 6.79E-06 2.23E-01 NA NA NA NA NA NA NA NA sorghum for grain 2.95E-02 NA 8.70E-06 2.61E-01 NA NA NA NA NA NA NA NA sorghum for silage (1) (1) (2) (2) (2) (2) NA NA NA NA NA NA potatoes 5.93E-03 NA 7.70E-06 2.94E-01 NA NA NA NA NA NA NA NA rye 2.82E-02 NA 8.35E-06 2.73E-01 NA NA NA NA NA NA NA NA alfalfa hay 3.31E-03 3.10E-02 (2) (2) (2) (2) NA NA NA NA NA NA other hay 4.57E-03 3.38E-03 (2) (2) (2) (2) NA NA NA NA NA NA soybeans 1.80E-03 6.57E-02 1.22E-06 1.39E-02 4.47E-05 5.07E-01 NA NA NA NA NA NA cropland pasture 0.00E+00 6.69E-03 (2) (2) (2) (2) NA NA NA NA NA NA noncropland pasture 0.00E+00 NA (2) (2) (2) (2) NA NA NA NA NA NA

rice 2.45E-02 NA 6.83E-06 3.76E-01 NA NA NA NA NA NA NA NA beef 8.42E-02 1.57E-01 2.89E-05 4.86E-01 5.40E-05 1.57E-01 2.87E-01 5.55E-02 9.85E-05 1.90E-05 1.65E+00 3.20E-01 milk 7.46E-03 7.68E-03 1.22E-05 2.37E-01 1.26E-05 7.68E-03 1.28E-02 3.11E-03 2.10E-05 5.10E-06 4.07E-01 9.87E-02 pork (pigs/hogs) 1.18E-01 9.93E-02 2.51E-05 8.50E-01 2.10E-05 9.93E-02 4.71E-02 2.43E-02 9.98E-06 5.16E-06 3.38E-01 1.75E-01 eggs (layers) 4.07E-02 3.46E-02 2.85E-05 3.24E-01 2.42E-05 3.46E-02 5.36E-02 2.30E-02 3.75E-05 1.61E-05 4.27E-01 1.83E-01 broilers 5.19E-02 4.41E-02 2.44E-05 2.83E-01 2.07E-05 4.41E-02 6.87E-02 2.96E-02 3.23E-05 1.39E-05 3.75E-01 1.62E-01 turkey 6.33E-02 5.42E-02 4.03E-05 3.11E-01 3.45E-05 5.42E-02 7.28E-02 3.19E-02 4.64E-05 2.03E-05 3.57E-01 1.57E-01

Notes:  

(1)  Allocated  all  fertilizer  to  the  grain  crop.    (2)  These  values  were  calculated  for  crops  fed  to  humans  thus  if  it  is  assumed  that  a  crop  is  not  for  human  consumption  no  value  appears  here.  

18

Table S14. Comparison of manure estimates in this study and assumptions from other studies1.              Note: 1. Values adapted from Boyer et al., 2002.    Table S15. Total manure estimate comparisons.

Animal kg N

manure - low, 2002

kg N manure -

NANI, 2002

kg N manure -

high, 2002

Kellogg estimate,

19971

all cattle 4.18E+09 4.48E+09 5.26E+09 4.41E+09

beef 3.41E+09 3.50E+09 3.71E+09 --

dairy 7.63E+08 9.85E+08 1.55E+09 9.07E+08 pigs/hogs 3.24E+08 4.14E+08 1.27E+09 5.42E+08 all poultry 1.88E+08 1.44E+09 1.62E+09

8.94E+08 layers 7.00E+07 2.33E+08 4.13E+08 broilers 7.64E+07 1.02E+09 1.02E+09 turkey 4.17E+07 1.88E+08 1.89E+08 sum cattle, swine, poultry 4.69E+09 6.34E+09 8.16E+09 5.85E+09

Note: 1. Kellogg et al., 2000.

Animal

Value used in

this study

David et al., 2010

VanHorn, 2002

Thomas & Gilliam 1997

Bleken & Bakken,

1997 van Horn,

1998

van der Hoek &

Bouwman, 1999

Smil, 1999 SCS, 1992

N in Animal Manure (kg-N/animal/yr) beef 58.5 58.4 58.6 44.00 66.60 58.51 40.70 50.00 41.72 milk 121.0 -- 166.8 120.00 93.90 121.00 140.50 80.00 79.47 pigs/hogs 5.84 9.855 5.85 6.10 4.34 5.84 10.46 10.00 19.70 sheep 5.00 -- -- 6.70 5.00 25.00 5.00 13.04 horse 40.0 -- -- 50.00 40.00 45.00 35.00 27.81 layers 0.55 1.241 0.54 0.83 0.61 0.55 0.81 0.30 0.21 broilers 0.07 0.365 0.07 0.39 0.03 0.07 0.57 0.30 0.55 turkey 0.39 1.606 0.37 1.29 0.34 0.39 0.50 0.30 0.37 goats 5.00 -- -- 12.30 5.00 19.90 -- --

19

Table S16. Comparison of ammonia emission estimates in this study and assumptions from other studies1

Animal

Values used in

this study

Cass et al. 1982

ApSimon et al., 1987

Buijsman et al., 1987

Kruse et al 1989

Moller & Schieferdecker,

1989

Asman 1990

Lee, 1994

Bouwman et al., 1997

van der Hoek, 1998

NH3 Emission (kg-N/animal/yr)

beef 18.83 -- 15.87 -- -- 22.10 -- -- 7.80 11.76 milk 18.83 27 15.87 14.80 19.31 22.10 20.70 27.00 20.40 23.44 pigs/hogs 4.20 4.5 2.35 2.30 2.86 5.20 3.96 1.60 4.00 3.98 sheep 2.77 2.7 2.2 2.55 2.68 3.00 1.57 0.70 0.64 1.10 horse 10.03 33 25.99 7.73 31.60 15.00 10.30 -- 7.60 6.58 layers 0.20 0.24 0.19 0.21 0.23 0.22 0.26 0.12 0.20 0.30 broilers 0.14 0.24 0.19 0.21 0.23 0.22 0.26 0.12 0.20 0.30 turkey 0.71 0.66 0.19 0.21 0.23 0.22 0.26 0.10 0.20 0.76 goats 5.26 -- -- -- -- -- -- -- 0.58 1.1

Note: 1. Values adapted from Boyer et al., 2002. Cass et al., Kruse et al., Asman 1990, Lee 1994 derived from Battye et al., 1994.

20

Table S17. Comparison of animal N Requirements in this study and others.

NANI descriptor NANI N requirement

Boyer descriptor

Low from Boyer (2002)

High from Boyer et al

(2002)

Canadian descriptor (Statistics

Canada, 2003)

Canadian value

Low value High value

fattened cattle 50.3 beef cattle 51.3 74.6 Steers & Heifers Slaughter 77.9 50.3 77.9

milk cows 130.8 dairy cow 126.7 177 Dairy Cows 105.3 105.3 177

hogs for breeding 13.8 pigs & hogs 5.85 14.93 Sow and Bred Gilts 25.2 5.85 25.2

hogs for slaughter 24 pigs & hogs 5.85 14.93 Boars 19.8 5.85 24.0 chicken layers 0.8 chickens (layers) 0.84 1.17 Layers 0.7 0.7 1.17

breeding turkeys 2.1 Turkeys 0.62 2.12 Turkeys 0.5 0.5 2.12

chicken pullets 0.4 chickens (broilers) 0.08 1.03 Chickens 0.08 0.08 1.03

chicken broilers 0.8 chickens (broilers) 0.08 1.03 Chickens 0.08 0.08 1.03

slaughter turkeys 2.1 Turkeys 0.62 2.12 Turkeys 0.5 0.5 2.12 beef breeding

herd 60.9 beef cattle 51.3 74.6 Beef cattle average 75.1 51.3 75.1

beef calves 19.9 young cattle 57.7 74.1 Bull calves < 1yr 19.3 19.3 74.1

dairy calves 10.6 young cattle 57.7 74.1 Other dairy calves 39.2 10.6 74.1

beef heifers 40.5 -- -- -- Avg of >1 yr and <1 yr dairy heifer 47.0 40.5 47.0

dairy heifers 43.5 -- -- -- dairy heifer >1 yr 54.8 43.5 54.8

beef stockers 37.6 -- -- -- Average of Beef Rep Heifers >1

and <1 yr 46.6 37.6 46.6

dairy stockers 37.6 Dairy Cattle 76.8 37.6 76.8

sheep 14.5 sheep 5.97 27.6 Slaughter lamb 3.8 3.8 27.6 horses 44.8 horses 44.8 44.8 Horses 74.7 44.8 74.7 goats 5.97 goats 5.97 23.7 Slaugher lamb 3.8 3.8 23.7

21

3. Additional discussion regarding LCA studies Studies were included in the de Vries & de Boer review based on the following criteria: (1) conducted in an OECD country (specifically, United Kingdom, European Union, New Zealand); (2) non-organic system (3) primarily engaged in the production of pork, chicken, beef, milk or eggs; (4) attributional LCA, i.e., a study of the status quo operations of the existing system, as opposed to consequential LCA which considers the consequences associated with a change in demand; (5) economic allocation applied to products and co-products and (6) the LCA had to include at least from cradle to farm gate (2010). The assumptions in this study overlap with the de Vries & de Boer criteria with the exception of criterion five and the lack of consideration of upstream, on-farm and transportation-related energy consumption in the LCA. Possible implications of these decisions are discussed below. Details regarding the calculation of eutrophication potentials for numerous studies are provided in Table S18. Table S18. Nitrogen and Phosphorous Contribution to Eutrophication Potential1

Study Product Location N, P, N&P included? N to EP P to EP Notes

Thomassen et al., 2008

Milk The Netherlands

N & P 32% nitrate; 12% ammonia

53% phosphate

Cederberg & Matteson, 2000

Milk Sweden N & P 94% 6% (Based on Fig 5)

Williams et al., 2006

Pork, Beef, Chicken, Eggs, Milk

United Kingdom

N & P 100% 0% Assume P is applied in direct relation to crop need, no excess, except potatoes.

Zhu-XueQin & Van Ireland, 2004

Pork The Netherlands

N & P 37% 63% EP values calculated solely off of nutrient inputs and plant uptake, total nutrients in manure attributed to EP.

Cederberg & Flysjo, 2004

Milk Sweden N & P 87-88% 12-13% (Based on Table 4.11; organic estimate not included)

Haas et al., 2001

Milk Germany N & P 63 – 44% 37 – 56% (Based on Table 6; organic estimate not included)

Note: 1. Of the remaining studies in the de Vries & de Boer review paper, could not locate the Cederberg and Darelius, 2002 nor the Blonk et al references. There was not enough data in Katajajuuri, 2008; Mollenhorst et al., 2007; Thomassen et al., 2009; and Hospido et al., 2003 to determine N to P contributions to EP. Casey and Holden, 2005 & 2006 did not calculate EP.

22

4. Study Results for Functional Unit Impact per kcal In addition to calculating GHG, N, and land area occupied for kg of commodity and kg of protein we also calculated for impact categories per kilocalorie. Kilocalorie assumptions are provided on Tables S4 and S12.

Figure S3. Grams of Nitrogen Inputs (Fertilizer, Fixation) and Output (Manure-N, NH3-N) per Kilocalorie (kcal) of Agricultural Commodity

Figure S4. Grams of Greenhouse Gas Emissions (GWP 100-yr) per kcal Agricultural Commodity

Figure S5. Grams of Greenhouse Gas Emissions (GWP 20-yr) per kcal Agricultural Commodity

Figure S6. Land use (m2) per kcal Agricultural Commodity

0.00

0.05

0.10

0.15

0.20

beef

milk

pork

eggs

chick

en

turk

ey

corn

wheat

oats

barley

potato

es

rye

soyb

eans

rice

g N

/kca

l

NH3-N Manure-N N Fixation Fertilizer

0

1

2

3

4

5

6

7

beef

milk

pork

eggs

chick

en

turkey

corn

wheat

oats

barley

potatoes

rye

soyb

eans

rice

g C

O2e

(100

yr)

/kca

l N2O-Manure Mgmt

CH4-Manure Mgmt

CH4-Enteric

CH4-Crop

N20-Crop

0 2 4 6 8

10 12 14 16 18 20

beef

milk

pork

eggs

chick

en

turkey

corn

wheat

oats

barley

potatoes

rye

soyb

eans

rice

g C

O2e

(20

yr)/k

cal N2O-Manure Mgmt

CH4-Manure Mgmt CH4-Enteric CH4-Crop N20-Crop

0.00

0.01

0.02

0.03

0.04

0.05

beef

milk

po

rk

eggs

chick

en

turke

y co

rn

wheat

oats

barle

y

potat

oes rye

soyb

eans

ric

e

m2 /k

cal

Pastureland

Hay Land

Cropland

Direct Land

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