APPENDIX C

AGRICULTURE

The agricultural system is derived from standard nutritional requirements for adult men and women and for children. The space colony population is used to normalize these requirements to that of a "typical" person weighing 60 kg as shown in table 5-16.

TABLE 5-16 (gif format)

TABLE 5-16.- HUMAN NUTRITIONAL REQUIREMENTS

			Daily requirement per person (ref. 1)
	Body weight kg	Colony population	Calories	Protein, g
Adult men	70	4853	2900	70*
Adult women	58	4633	2100	58*
Children**	32	864	2150	54
Weighted average	61	-	2479	63.3

*Colony workers may require higher protein intake due to
strenuous workloads.
**Assumes a normal age and sex distribution of children under
18 years old.

These requirements are met by an average daily diet which is shown in table 5-17 (a) which also includes the caloric and nutritional values calculated for this diet. The nutritional requirements are met and an excess of protein is provided by a substantial margin.

TABLE 5-17 (a) (gif format)

TABLE 5-17.- (a) AVERAGE DAILY SPACE COLONY DIET (g/PERSON)

Source	Amt, g	Calories, kcal	Carbo- hydrates, g	Fats, g	Protein, g
(Meat) Trout Rabbit Beef Chicken	40 40 40 40	78 64 142 49	0 0 0 0	4.6 3.2 12.8 1.3	8.6 8.4 6.3 8.8
(Produce) Eggs Milk	24 500	39 330	0.2 24.5	2.8 19.0	3.1 17.5
(Dry plant produce) Wheat Rice Sugar	180 100 100	608 363 385	130.1 80.4 99.5	3.6 .4 0	24.3 6.7 0
(Vegetables and Fruit) Carrots Lettuce Peas Apple Potato Tomato Orange	100 100 100 100 100 100 100	42 14 126 56 76 22 51	9.7 2.5 21.6 14.1 17.1 4.7 12.7	0.2 .2 .6 .6 .1 .2 .1	1.1 1.2 9.5 .2 2.1 1.1 1.3
Totals	1814	2445	417.1	49.7	100.2

Note: Calculated from reference 2.

TABLE 5-17 (b) (gif format)

TABLE 5-17.- (b) VITAMIN AND MINERAL COMPOSITION OF AVERAGE DIET

Nutrient	Space Colony average diet*	Recommended daily allowances**
Vitamin A (iu)	14,399	4915
Vitamin C (mg)	144	56
Niacin (mg equiv)	33	15
Riboflavin (mg)	2.1	1.6
Thiamin (mg)	2.2	1.2
Calcium (g)	0.88	0.82
Phosphorus (g)	1.57	0.82
Iron (mg)	17.0	13.6
Potassium (mg)	3,549	Not listed
Sodium (mg)	1,680	Not listed
Linoleic acid (g)	1	Not listed
Cholesterol (mg)	319	Not listed

*Average diet evaluated in cooked form. Source: Watt, B.K., and Merrill, A. L. Composition of Food. Agricultural Handbook, No. 8, Washington, D.C. Revised 1963.
**Each value is weighted to reflect the population composition of 8 percent children (weighing 28 kg), 47 percent adult males (70 kg), and 45 percent adult females (58 kg). Source: Recommended Dietary Allowances, 7th edition, National Academy of Sciences, 1968.

A more careful analysis of the colony's protein requirement could provide savings in meat requirements and, in turn, provide substantial savings in the required land area for plants.

The diet is treated as a daily average of all components as if each colonist ate a small portion of each foodstuff each day. In reality, of course, the colonists would eat a varied selection that over time averages to this diet. The individual components of the diet are chosen to provide adequate variety for both-nutritional and psychological purposes. These components are meant to be representative of classes of foods and not specifically limited to these items. For example, pork could be considered as a feasible diet component with feed and area requirements intermediate between beef and rabbits. In addition, it should be explicitly stated that this diet represents typical American preferences and does not recognize ethnic or religious dietary preferences. It is reasonable to expect, however, that such preferences could be adopted if desired.

The meat in this diet dictates the requirement for a stable herd of animals for which the rates of birth and slaughter are equal. In effect, each colonist has 26 fish, 6.2 chickens, 2.8 rabbits and about 1/7 of a cow (see table 5-5). The plant diet for these animals plus that for humans then forms a total requirement for all plants as given in table 5-18.

TABLE 5-18 (gif format)

TABLE 5-18.- TOTAL PLANT REQUIREMENTS, g/PERSON/DAY

	Sorghum*	Soybean*	Wheat*	Rice*	Fruits and vegetables	Corn*	Other	Totals
Man	-	-	225	125	-	937	125a	1412
Cattle Chickens Rabbits Fish	217 - 100 -	100 170 100 100	- - - -	- - - -	- 30 20 -	- - - -	633 b 37 c - 81 d
Totals	317	470	225	125	50	937	758	2882

Notes:
*Dried grain.
a Man also utilizes 125 g/person/day of sugar extracted from sorghum.
b Cattle also utilize 633 g/person/day roughage from sorghum and soybean.
c Chickens also utilize 37 g/person/day fish meal.
d Fish also utilize 81 g/person/day animal meal from meat processing byproducts.
(c and d are not included in totals)

Food processing byproducts and silage are extensively used in satisfying the animal diet. Implicit in this derivation is allowance for yields in meat dressing and food processing, for moisture and silage content of the grains, and for the metabolic requirements of the various animals. These factors are given in table 5-19, parts A-J, along with the carbon, nitrogen, hydrogen, and oxygen elemental balance for each step in the food chain (refer to fig. 5-16).

TABLES 5-19 A-J listed in gif format

• Table 5-19 A
• Table 5-19 B
• Table 5-19 C
• Table 5-19 D
• Table 5-19 E
• Table 5-19 F
• Table 5-19 G
• Table 5-19 H
• Table 5-19 I
• Table 5-19 J

TABLE 5-19.- FACTORS OF METABOLIC REQUIREMENTS

A. diet requirements for man (from table 5-17 (a)), g/day

	Total	C	H	O	N
(Meat) Trout Rabbit Beef Chicken	40 40 40 40	7.6 6.4 12.8 5.3	4.2 4.2 4.4 4.2	27.0 28.2 21.9 29.3	1.2 1.2 .9 1.2
	160	32.1	17.0	106.4	4.5
(Produce) Egg Milk	24 5000	3.7 32.5	2.6 54.0	17.3 411.0	.4 2.5
	524	36.2	56.6	428.3	2.9
(Dry plant products) Wheat Rice Sugar	180 100 100	67.5 35.8 40.0	13.9 7.6 7.0	95.2 55.7 53.0	3.4 .9 -
	380	143.3	28.5	203.9	4.3
(Vegetables, fruit) Carrot Lettuce Pea Apple Potato Tomato Orange	100 100 150 100 100 100 100	4.6 1.7 13.6 6.2 8.0 2.5 5.8	10.6 10.9 15.3 10.4 10.2 10.8 10.5	84.6 87.2 119.7 83.3 81.4 86.5 83.5	.2 .2 1.4 .1 .3 .3 .2
	750	42.4	78.7	626.2	2.7
(Total food intake) above H2O	1814 750	254 -	181 83	1365 667	14 -
	2564	254	264	2032	14

C/H/O/N ratios for food calculated from data of reference 2.

TABLE 5-19.- B

Mass balance on one person

	Total	C	H	O	N
(In) Food O2 H2O	2564 686 400	254 - -	264 - 44	2032 686 356	14 - -
(Out) CO2 H2O Wastes	857 857 1936	231 - 23	- 94 214	626 763 1685	- - 14

TABLE 5-19.- C

Mass balance on food processing

	Total	C	H	O	N
(In) Meat and produce Plant H2O	724 1412 750	84 233 -	77 134 83	556 1037 667	7 8 -
(Out) Food Kitchen waste	2564 322	254 63	264 30	2032 228	14 1

Based on: 20% of meat and plant materials are lost to waste.

TABLE 5-19.- D

Mass balance on animal harvesting

	Total	C	H	O	N
(In) Meat and produce	1168	138	126	890	14
(Out) To nonhuman To food processing	444 724	54 84	49 77	334 556	7 7

Based on: 33% of milk to nonhuman food processing. Efficiencies of meat harvest (dressed/animal)
fish = 35%
steers = 55%
rabbits = 65%
chickens = 60%

TABLE 5-19.- E

Mass balance on nonhuman food processing

	Total	C	H	O	N
(In) Fish Beef Chicken Rabbit Milk	93 41 33 27 250	18 13 4 3 16	10 5 4 3 27	62 22 24 20 206	3 1 1 1 1
(Out) Meal H2O	118 326	54 -	13 36	44 290	7 -

Based on: Animal meal has 15% moisture.

TABLE 5-19.- F

Mass balance on animals

	Total	C	H	O	N
(In) H2O Nonhuman veg Meal O2	3853 1470 118 747	- 575 54 -	424 121 13 -	3429 736 44 747	- 38 7 -
(Out) H2O CO2 Meat, milk,eggs waste	1494 939 1168 2587	- 254 138 237	164 - 126 268	1330 685 890 2051	- - 14 31

TABLE 5-19.- F.1.

Animal food requirements

Beef steer: 1 steer for 11 persons Harvested at 400kg after 16 months Metabolic requirements for 1/11 250 kg steer 300 g sorghum mix/day 200 g soybean mix/day

Roasting chicken: 5.6 chickens/person Harvested at 2.6 kg after 25 weeks Metabolic requirements for 5.6 chickens at 1.1 kg each 37 g fish meal/day 150 g soybean/day

Rabbits Harvested at 3.4 kg after 125 days Metabolic requirements for 2.8 rabbits at 1.8 kg each 100 g sorghum/day 100 g soybean/day 20 g corn/day

Dairy cattle 400 kg cow produces 12.45 kg milk/day Metabolic requirements for 1/16.6 cow at 400 kg 350 g sorghum mix/day 100 g soybean mix/day

Laying hens 1.5 kg hen lays 5 eggs/week, 54 g/egg Metabolic requirements for 6/10 hen at 1.5 kg 20 g soybean/day 30 g corn/day

Fish Harvested at 2 kg in 1 yr Metabolic requirements for 26 fish at 1 kg each 100 g soybean/day 81 g animal meal/day

Summary

Plant Matter	Total	C	H	O	N
Beef steer Roasting chicken Rabbits Dairy cow Laying hen Fish	500 150 220 450 50 100	187 67 89 167 20 45	40 13 19 36 4 9	263 62 105 240 25 41	10 8 7 7 1 5
Total	1470	575	121	736	38
(Animal meal) Roasting chicken Fish	37 81	17 37	4 9	13 31	3 4
Total	118	54	13	44	7

TABLE 5-19.- F.2.

Animal metabolic requirements, g/day [Based on animal biomass of F.1. above.]

	In		Out
Animal	O2	H2O	CO2	H2O	Meat produce	Waste
Beef steer	180	910	230	450	91	819
Roasting chicken	168	616	210	146	83	532
Rabbit	88	302	110	189	77	235
Dairy cow	220	1840	275	690	750	795
Laying hen	23	85	29	19	24	86
Fish	68	100	85	-	143	121
Total	747	3853	939	1494	1168	2588

Data based on the following: Food requirements (ref. 22). For caloric and nitrogen
requirements - diets calculated
Metabolism (ref. 22) CO2 calculated by O2/0.8
Chicken egg production (ref. 23). Fish Food and metabolism; personal communication, Chris Brittleson, Wisconsin Dept. of Natural Resources, Nevin Fish Hatchery, Madison, Wisconsin

TABLE 5-19.- G

Mass balance on non-human food processing

	Total	C	H	O	N
(In)Sorghum Sorghum roughage Soybean Soybean hay Corn	1406 1829 2103 883 220	119 152 211 75 18	144 188 222 91 23	1138 1485 1646 713 178	5 4 24 4 1
Total	6441	575	668	5160	38
(Out) to animals Water	1470 4971	575 -	121 547	736 4424	38 -

Based on:
Sorghum roughage 14.5% moisture after drying
Soybean hay 10.8% moisture after drying
Two times dry roughage or hay as seed.

TABLE 5-19.- H

Mass balance on plant harvest

	Total	C	H	O	N
(In) From fields	16,273	1,347	1682	13,172	72
(Out) To food processing To nonhuman food H2O Waste	1,412 6,441 1,205 7,215	233 575 539	134 668 133 747	1,037 5,160 1,072 5,903	8 38 26

TABLE 5-19.- H.1

Plants from field

Material	Total	C	H	O	N
Sorghum Soybean Corn Wheat Rice Fruits and vegetables	4080 4620 1034 3018 1647 1874	341 425 86 254 135 106	419 481 107 309 168 198	3309 3678 838 2442 1341 1564	11 36 3 13 3 6
Total	16,273	1,347	1,682	13,172	72

TABLE 5-19.- H.2

To food processing

Material	Total	C	H	O	N
Wheat Rice Vegetables Sugar	225 125 937 125	85 45 53 50	17 9 99 9	119 70 782 66	4 1 3
Total	1412	233	134	1037	8

TABLE 5-19.- H.3

Drying Human food - wheat materials balance

Material	Total	C	H	O	N
(In) From field	3018	254	309	2442	13
(Out) To food processing H2O Waste	225 781 2012	85 169	17 86 206	119 695 1628	4 9

Based on:
1/3 dry weight is grain, Harvested at 80% moisture.

TABLE 5-19.- H.4

Drying Human food - rice materials balance

Material	Total	C	H	O	N
(In) From field	1647	135	168	1341	3
(Out)To food processing H2O Waste	125 424 1098	45 - 90	9 47 112	70 377 894	1 - 2

Based on:
1/3 dry weight is grain, Harvested at 80% moisture.

TABLE 5-19.- H.5

Harvest waste

Material	Total	C	H	O	N
Fruit and vegetable Sorghum roughage Soybean roughage Corn roughage Wheat roughage Rice roughage	937 845 1634 814 2012 1098	53 70 139 68 169 90	99 87 168 84 206 112	782 686 1319 660 1628 894	3 2 8 2 9 2
Total	7340	589	756	5969	26
Less extracted from sorghum	125	50	9	66	-
Harvest waste	7215	539	747	5903	26

Based on: Soybean and grain roughage 80% moisture.
Fruit and vegetable waste 50% of harvest and same composition. Corn is 1/5 of dry corn plant.

TABLE 5-19.- I

Mass balance on plants

	Total	C	H	O	N
(In)Irrigation water Recycle water Nutrients CO2	168,750 61,250 93 235,082	- - - 1347	18,563 6,737 21 -	150,187 54,513 - 3,642	72 -
(Out) Plants Irrigation return Evapotranspiration O2	16,273 50,000 164,900 3,909	1,347 - - -	1,682 5,500 18,139 -	13,172 44,500 146,761 3,909	72 - - -

Based on: 30.5 cm water on 45 m^2 in 60-day season, 50,000 g irrigation return.

TABLE 5-19.- J

Mass balance waste processing

	Total	C	H	O	N
(In) Wastes O2	62,060 2,476	862 -	6759 -	54,367 2,476	72 -
(Out) CO2 NH4 H2O	3,193 93 61,250	862 - -	- 21 6738	2,331 - 54,512	- 72 -

Sorghum is chosen as a principal component of the animal diet because it can be produced in excellent yield and because it provides a source of protein (11 percent) while also providing silage and sugar. Protein make-up for the animal diet is provided from soybean (34 percent) and from meat processing byproducts.

From the quantitative requirements for each plant component, total plant growing area requirements can be obtained based upon estimates of crop yields as presented in table 5-4.

The success of the colony's agricultural systems rests entirely upon the photosynthetic productivity. Crops were estimated assuming a yield double that of the world record for that crop, as shown in table 5-20.

TABLE 5-20 (gif format)

TABLE 5-20.- CROP YIELDS

			Terrestrial Yields		Colony yields
Crop	Record yield	Reference	g/m^2/season	Season, day	g/m^2/season	Season, day	g/m^2/day
Wheat Rice Soybean Corn Sorghum	14 tons/ha 266 bu/ha 9000 kg/ha 26500 kg/ha 675 bu/acre	24 25 26 25 25	1400 1596 900 2650 3780	100 100 100 100 100	2800 3192 1800 5300 7560	90 90 90 90 90	31 35 20 58 83
Tomatoes Lettuce	67 tons/ha 24 tons/ha	5 5	6700 2400	~70 ~70		70 as veg.	132

Unit weights:
Rice 60lb/bu
Sorghum 56lb/bu
Soybean 60 lb/bu
Corn 56 lb/bu

Conversion factors
1 ha = 100 X 100 = 10^4 m^2

1 bu = 35.24 liters
1 ton = .0906 tonnes (t)

In addition, a factor of 1.1 improvement is obtained by shortening the growing season from 100 to 90 days. The record yield data come from harvests under good but not ideal or controlled growing conditions. Comparison of typical terrestrial and space colony growing conditions is presented in table 5-21.

TABLE 5-21 (gif format)

TABLE 5-21.- PHOTOSYNTHETIC PRODUCTIVITY ENHANCEMENT

Factor	Terrestrial	Space Colony
Light intensity	Reduced by atmosphere and clouds	Greater by 7.5
Photo period	~12 hr	Can be 24 hr
pCO2	17 Pa (0.13 mm Hg)	400 Pa (3 mm Hg) greater in growing area
Water	Sometimes dependent on rainfall	Irrigated regularly
Temperature	No control	Optimized for species
Season	1 per year in many areas	4 per year
Crop damage from weather	Hail, rain, wind	None
from pests and insects	5-15 percent loss of crop	None*
from weeds	2.5 to 5 percent loss of crop	None*
from disease	10 to 60 percent loss of yield	None*

*Controlled by quarantine.

Including the shortened season, the net improvement is a factor of 2.2 which is further enhanced by harvesting 4 crops per year. Thus the farmer in a typical American Midwestern farm who produces 100 bushels of corn per acre in a single season year would look with astonishment on the space colony farmer who produces 4164 bushels of corn from a single acre in his 4-season year. While this factor of 40 is substantial, it is believed to be credible since a portion of it is derived from year-round growing. Substantiation of crop yields is required and can be obtained through careful study under controlled conditions (and most of the research could be performed on Earth). The improvement that has already been achieved for certain vegetables in Abu Dhabi (ref. 5) is shown in table 5-22.

TABLE 5-22 (gif format)

TABLE 5-22.- INCREASED PRODUCTIVITY FACTORS*
IN VEGETABLES (ref. 24)

Cabbage	2.59
Cucumber	8.48
Eggplant	12.63
Lettuce	2.33
Okra	4.73
Tomato	2.37
Turnip	7.14

*Under greenhouse conditions.

The summer study did not pursue the issue of food reserves, design margins and safety factors with respect to agriculture. Due to the importance and fragility of the agricultural system further study should consider this issue. In general, it was felt desirable to produce some excess food continuously, store some of the excess as reserve, and recycle the remainder. In fact, it would seem wise to design the system such that the colony could survive on the output of two of the three agricultural units for a period of several months if some disaster ruined production in one of the areas. Also, the study did not pursue microbial and insect ecology but did assume that these important areas could be resolved upon further study.

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