Thomas L. AckerChelsea Atwater and,Dean Howard Smith

Research issue

Modern industrial farming technologies for growing fruits and vegetables have changed substantially in recent decades.

In many locations such as Arizona, these industries are highly energy and water intensive operations.

As such, the sustainability of these operations is called into question.

The economic, social and climate implications of energy use in agriculture are worth further discussion.

The Subterranean Forest

Hypothesis: the social-metabolic regime of a society is limited by the conversion of energy to allow for the harvest of more energy.

Each human must expend a certain amount of energy harvesting food, in whatever form, to allow for continued life to allow for more food harvesting and so on.

If an individual’s energy budget is such that more energy is expended capturing energy than is captured, then, obviously, the individual will die.

Budgeting

The metabolic rate of the human body is such that perhaps 20% of the energy consumed can be directly applied to capturing more energy through hunting, gathering or working in the fields.

Thus, the individual must harvest at least 5 units of energy for each unit of energy spent in the process of harvesting in order to survive.

Any deficit below the 1:5 ratio will be unsurvivable.

Any surplus above the ratio will allow for additional work unrelated to energy harvesting such as singing and dancing. Other authors estimate smaller and greater estimates.

Efficiency

A megafauna hunting society estimates an output of 40-60 megajoules (MJ) per hour of labor.

Reduced to a productivity of 4-6 MJ of output per hour for small game hunting.

With the advent of agriculture the typical output of a worker increased to 12-20 MJ per hour of labor.

Social Changes

The socio-economic basis of the agrarian civilizations lies in the tributary appropriation of surplus. This means that the producers (peasants) have to regularly contribute a part of their harvest as rent, tribute or tax of which a “ruling class” with its retinue of specialists and servants are supported and provided for. The result is a fortifying vertical social differentiation, normally in the following categories:

peasants, landlords (aristocracy), warriors, priests (scholars), the court (rulers, bureaucrats), craftsmen, merchants. In addition there is usually a lower class that can include up to 10% of the population earning their livelihood as wage laborers, barterers, beggars or thieves. (Sieferle, 2001, page 25)

Consequences

The social organizational changes, due to the metabolic change in society, eventually led to the need for yet a new energy regime as the populations grew and a solar based energy regime was no longer sustainable. Thus fossil fuels entered the energy budget and eventually the food stream.

Photosynthesis

Twidwell and Weir estimate that the maximum efficiency of photosynthesis is 5%. They further estimate that the photosynthesis of cassava and cereal is 2% and 3% respectively.

Can it Be?

A solar based energy regime must convert one unit of human energy into, grossly, between 100 and 250 units of harvested solar energy to be merely survivable.

The energy regime reached the capacity, so… In a solar based energy regime, the

amount of energy embodied in food production must always exceed the value of the energy necessary to produce and harvest that food. Industrial agriculture, reliant on fossil fuels and non-gravity fed irrigation, has completely turned the energy budget of growing food upside down.

Servings

CropSize

ounces Kcal refuseunit weightpounds

Broccoli 3.2 31 0.39 0.52

Cabbage 3.1 21 0.2 2.89

Cantaloupes 1.9 19 0.49 3.78

Cauliflower 3.5 25 0.61 2.27

Chile Peppers 2.6 30 0.27 0.41

Dry Onions 3 36 0.1 0.55

Head Lettuce 1.9 8 0.05 1.64

Honeydews 4.4 45 0.54 3.27

Leaf Lettuce 1.9 8 0.05 1.04

Potato 2.6 58 0 0.85

Romaine 1.7 8 0.06 1.66

Spinach 1.1 7 0.28 0.80

Watermelons 4.3 37 0.48 15.76

Calculations

Average weight= total weight/sample size

Weight/unit = average weight*16 Useable/unit=weight/unit *(1- refuse

%) Serving/unit= (useable/unit)/ serving

size

A Day Shopping 9/29/07

Cropsample

sizesample

ounces useable serve/unit

Broccoli 31 8.4 5.1 1.6

Cabbage 25 46.2 36.9 11.9

Cantaloupes 31 60.4 30.8 16.2

Cauliflower 22 36.4 14.2 4.1

Chile Peppers 31 6.6 4.8 1.8

Dry Onions 37 8.8 8.0 2.7

Head Lettuce 31 26.2 24.9 13.1

Honeydews 8 52.3 24.0 5.5

Leaf Lettuce 20 16.7 15.9 8.4

Potato 31 13.6 13.6 5.2

Romaine 25 26.5 24.9 14.6

Spinach 13 12.8 9.2 8.4

Watermelons/pound 10 16.0 8.3 1.9

Energy Used in Production

CropKcal/serve

operationsKcal/serve

highKcal/serve

lowKcal/serve

avg

Broccoli 5041 11432 10120 10776

Cabbage 344 1212 879 1045

Cantaloupes 212 807 632 719

Cauliflower 1158 3397 2939 3168

Chile Peppers 1312 6141 3444 4792

Dry Onions 417 1610 1236 1423

Head Lettuce 198 685 559 622

Honeydews 1127 3740 2852 3296

Leaf Lettuce 311 1076 878 977

Potato 819 1969 1437 1703

Romaine 165 536 490 513

Spinach 142 494 334 414

Watermelons 975 2338 1760 2049

Water Used in Production

Cropwater/serve

highwater/serve

lowwater/serve

avg

Broccoli 59.4 39.3 49.3

Cabbage 9.0 5.4 7.2

Cantaloupes 5.5 2.8 4.1

Cauliflower 21.6 14.6 18.1

Chile Peppers 69.3 28.0 48.6

Dry Onions 9.4 6.6 8.0

Head Lettuce 3.8 3.0 3.4

Honeydews 30.6 17.1 23.9

Leaf Lettuce 6.0 4.8 5.4

Potato 10.7 4.3 7.5

Romaine 3.4 2.7 3.1

Spinach 4.2 1.7 3.0

Watermelons 15.9 7.1 11.5

Efficiency

Kcal of production energy/Kcal of food energy

Gallons of water/Kcal of food energy

8 ounce glasses

Cropenergy efficiency

water efficiency

glasses of water

Broccoli 347.6 1.591 25.5

Cabbage 49.8 0.342 5.5

Cantaloupes 37.9 0.217 3.5

Cauliflower 126.7 0.725 11.6

Chile Peppers 159.7 1.621 25.9

Dry Onions 39.5 0.222 3.6

Head Lettuce 77.8 0.429 6.9

Honeydews 73.2 0.530 8.5

Leaf Lettuce 122.2 0.674 10.8

Potato 29.4 0.129 2.1

Romaine 64.1 0.384 6.2

Spinach 59.2 0.424 6.8

Watermelons 55.4 0.311 5.0

Inputs required for 1 calorie output of food product

Crop Acker- Input High Acker- Low Pimental

Corn 82.4 23.3 2.5

Sorghum 15.9 13.8 14.4

Oranges 203.2 184.4 1.7

Spinach 70.6 41.9 .23

Potatoes 34.4 23.3 1.2

New FrontiersFood price price/serve price/cal cal/$Broccoli 2.19 1.370 0.044 22.6Cabbage 0.89 0.075 0.004 281.1Cauliflower 1.59 0.392 0.016 63.7Chiles Peppers 6.99 3.783 0.126 7.9Dry Onions 1.19 0.449 0.012 80.2Head Lettuce 1.99 0.152 0.019 52.7Leaf Lettuce 1.79 0.214 0.027 37.3Potato 1.29 0.246 0.004 235.4Romaine 1.71 0.117 0.015 68.5Spinach 2.99 0.358 0.051 19.6Chicken breasts - skinned 4.79 1.198 0.007 142.0Chicken thighs 2.99 0.748 0.003 321.1Ground beef 80% 4.29 1.073 0.004 259.2Sirloin 7.99 1.998 0.005 184.2Ribeye 12.99 9.743 0.018 54.6

Pork loin 6.49 1.623 0.007 150.4Salmon 8.99 2.248 0.010 103.7Milk gallon 1% 7.29 0.456 0.004 263.4Bread whole wheat 3.49 0.244 0.003 368.4Eggs - storeEggs cage free 3.39 0.283 0.004 247.8OJ 3.69 0.500 0.005 219.9Raisin Bran 4.99 0.618 0.004 275.2Cornflakes 4.99 0.594 0.005 185.2Frosted Flakes 4.99 0.382 0.003 314.2Bacon 5.79 0.241 0.004 248.7Sliced ham 5.49 1.569 0.022 44.6Salad Dressing Ranch 4.29 0.536 0.004 223.8Choc ice Cream 4.99 0.416 0.003 360.7

SafewayCrop price price/serve price/cal cal/$Broccoli 1.69 1.057 0.034 29.3Cabbage 0.59 0.050 0.002 424.0Cauliflower 1.69 0.417 0.017 59.9Chiles Peppers 1.99 1.077 0.036 27.9Dry Onions 0.99 0.373 0.010 96.4Head Lettuce 1.29 0.098 0.012 81.3Leaf Lettuce 1.99 0.238 0.030 33.6Potato 1.29 0.246 0.004 235.4Romaine 1.99 0.136 0.017 58.9Spinach 1.49 0.178 0.025 39.3

Chicken breasts - skinned 2.99 0.748 0.004 254.2Chicken thighs 1.39 0.348 0.001 690.6Ground beef 80% 3.49 0.873 0.003 318.6Sirloin 4.49 1.123 0.003 327.8Ribeye 9.99 7.493 0.014 71.0

Pork loin 5.29 1.323 0.005 184.5Salmon 8.99 2.248 0.010 103.7Milk gallon 1% 2.69 0.168 0.002 654.3Bread whole wheat 2.59 0.118 0.002 509.7Eggs - store 2.29 0.191 0.002 471.6Eggs cage free 3.39 0.283 0.003 318.6OJ 7.69 0.481 0.004 228.9Raisin Bran 4.49 0.555 0.003 342.6Cornflakes 4.49 0.249 0.002 400.9Frosted Flakes 4.49 0.291 0.003 378.6Bacon 6.49 0.649 0.009 107.9Sliced ham 4.79 0.532 0.018 56.4Salad Dressing Ranch 3.79 0.237 0.002 591.0Choc ice Cream 6.45 0.538 0.004 260.5

Eating oil?

broccoli potatoesBTU/gal 139000 139000Kcal/BTU 3.97 3.97kcal/gal 551830 551830kcal/serving 10776 1703servings/gallon 51.20917 324.0341

128 128ounces of gas 2.499552 0.39502days of gas/gal 275.915 275.915ounces/day of gas 0.463911 0.463911

A Boring Diet

Kcal per day Gallons/day Ounces/day Glasses/day Crop695200 1.26 161.26 20.16 Broccoli99600 0.18 23.10 2.89 Cabbage

75800 0.14 17.58 2.20 Cantalopes

253400 0.46 58.78 7.35 Cauliflower

319400 0.58 74.09 9.26 Chiles Peppers

79000 0.14 18.32 2.29 Dry Onions

155600 0.28 36.09 4.51 Head Lettuce

146400 0.27 33.96 4.24 Honeydews

244400 0.44 56.69 7.09 Leaf Lettuce58800 0.11 13.64 1.70 Potato

128200 0.23 29.74 3.72 Romaine118400 0.21 27.46 3.43 Spinach

110800 0.20 25.70 3.21 Watermelons

DAY AS A VEGETARIAN BREAKFAST: 4 eggs = 320 calories 320*28= 8,960 ____________________ 8960 input to 320 output   SNACK: 1 oz. peanuts = 170 calories 170 * 1.4 = 238

LUNCH: Sushi! = 450 ¼ cup dry rice = 160 ¼ cup salmon = 90 1 in pod = 200 ____________________ 448 + 720 + 830 + 9198 = 11196 450 + 490 = 940 10781 input to 840 output

DINNER = 350 3 oz Spinach = 30 cal 1 med tomato = 35 cal 1 ear corn = 83 cal ½ c. cowpeas a.k.a. black eyed peas= 110

oz. broccoli = 44 cal  11196 + 6.9 +21 +207.5 +710.6

+805.64= 12946.64 840 + 302= 1142 12946.64 inputs for 1142 output  Dessert: 100 coffee with 1 oz sugar = 110 cal __________________________ 12141 + 398.2 = 12539.2 1098 + 100 = 1198 12539.2 input for 1198 output

10.5:1 Inefficiency

DAY AS A MEAT EATER BREAKFAST: 406 4 slices = 240 calories 8 oz milk = 86 calories 86*19 = 1634 1 orange = 80 calories 18090 input to 406 output

LUNCH: 265 3 slices beef = 135 calories 2 slices whole wheat bread = 110 cal 1 oz Spinach = 10 cal 2 slices tomato = 10

18090 + 4725 + 242 + 2.3 + 6 = 23065.3 406 + 135 + 110 + 10 + 10 = 761 23065.3 input to 761 output

SNACK: 1 oz. peanuts = 170 calories

DINNER = 520 4 oz chicken = 240 cal 1 cup = 60 cal baked potato w/ skin= 220

cal ___________________________

___ 23303.3 + 3840 + 41.4

+270.6 = 27455.3 931 + 520 = 1451 27455.3 input to 1451

output calories  

18.9:1 Inefficiency

ALTERNATIVE MENU

BREAKFAST: 335 1 c cooked oats =

145 cals 1 oz sugar = 110 cal 1 orange = 80

calories 1273.7 input to 335

output  

LUNCH 4 oz Shrimp = 70

cals 3 oz Spinach = 30

cal 1.1 oz. broccoli = 44

cal

1273.7 + 4865 +6.9 +805.64= 69496949 input to 479 output

14.5:1 inefficiency