Analysis of producing vegetable oil as an alternate fuel

Energy in Agriculture, 4 (1985) 189--205

189

Elsevier Science Publishers B.V., Amsterdam -- Printed in The Netherlands

ANALYSIS FUEL

OF PRODUCING

VEGETABLE

OIL AS AN ALTERNATE

A. F A R S A I E 1, J.V. DeBARTHE 2, W.J. KENWORTHY a, B.V. LESSLEY 4 and W.J. WIEBOLD 5

'Agricultural Engineering Department, 2Animal Science Department, 3Agronomy Department, 4Department of Agricultural and Resource Economics, College of Agriculture, University of Maryland, College Park, MD 20742 (U.S.A.) 5Agronomy Department, The Ohio State University, Columbus, OH (U.S.A.) (Accepted 24 April 1985)

ABSTRACT Farsaie, A., DeBarthe, J.V., Kenworthy, W.J., Leasley, B.V. and Wiebold, W.J., 1985. Analysis of producing vegetable oil as an alternate fuel. Energy Agric., 4: 189--205. Small-scale, on-farm oil production and extraction were evaluated for four oilseed crops produced in full-season or double cropping systems. Economic feasibility was determined b y calculating the per-liter cost of vegetable oil based on total costs of production and processing as well as credits for feeding values of the oilseed residues. Per-liter costs ranged from a high of $1.76 for soybean oil (no-till, full-season soybeans) to a low of $0.97 for the conventionally tilled winter rape/soybeans cropping system (processing labor not included) for a 25% vegetable oil/diesel fuel mix for a typical 240-ha farm. When processing labor charges were included, all per-liter costs were increased accordingly. Total energy and fuel energy inputs and outputs were analyzed for winter rape, soybean, sunflower, and peanut oils. All four oilseeds yielded a positive energy balance (output greater than input). The total energy output-to-input ratio ranged from 2.62 for conventional tillage sunflowers to 7.47 for no-till soybeans. The fuel energy output-toinput ratio ranged from 1.43 for conventionally tilled full-season soybeans to 13.52 for the no-till winter rape/sunflower cropping system.

INTRODUCTION The production of liquid fuels from agricultural products could minimize t h e i m p a c t o f f u e l s h o r t a g e s in t h e a g r i c u l t u r a l i n d u s t r y . O i l s e e d c r o p s c a n provide a fuel-grade product using relatively simple extraction and processing technology which could be performed on individual farms (Bettis et al., 1982). The feasibility of producing fuel from oilseed crops, however, depends not only on the energy and economics of oil production but also on the feeding value of the oilseed residues resulting from the oil extraction pro cess.

190 There is little information available on the commercial production of sunflowers, peanuts, and winter rape in the Mid-Atlantic Region. Soybeans have been widely grown in this area and contribute substantially to the region's economy. Furthermore, soybean producers have taken advantage o f the long growing season in the Mid-Atlantic Region to successfully utilize a double cropping system of planting soybeans following the harvest of a small grain to maximize the economic return on each hectare. To maximize farm oil production, a double cropping system of winter rape followed b y sunflowers or soybeans needs to be evaluated in the environmental conditions of this region. Currently most of the oilseed crops are processed to produce edible vegetable oil and oilseed meals. Over 62% of the world's edible vegetable oil in 1980 was derived from soybeans, sunflowers, peanuts and rapeseed (Bozzini, 1982). Each of these crops is adapted to production in the U.S.A.; however, with the exception of soybeans, most axe commercially grown only in limited regions of the country. Vegetable oils are promising fuels, particularly for diesel engines. The practicality of vegetable oils as diesel fuels has been sufficiently demonstrated to warrant further investigation of their effectiveness and to develop techniques that will permit their incorporation into agricultural operations, particularly in times of energy shortfall. An evaluation of energy and economic inputs and outputs is essential to facilitate farmer understanding and adoption of cropping systems that will optimize fuel oil and residue production. The objective of this paper is to report an interdisciplinary analysis of the energy and economic factors involved in small scale on-farm production, processing, and utilization of oils and animal feed by-products from four oilseed crops in seven cropping systems for the Mid-Atlantic Region. The cropping systems evaluated were: full-season peanuts; full-season soybeans, full-season sunflowers; double-cropped winter rape and soybeans; doublecropped winter rape and sunflowers; double-cropped winter wheat and soybeans; and double-cropped winter wheat and sunflowers. REVIEW OF LITERATURE Preliminary information (Farsaie et al., 1982)suggested that substantial oil can be produced from full-season plantings o f soybeans, sunflowers, and peanuts in the Delmaxva Peninsula. To substantially increase farm oil production, double-cropping systems composed o f two oilseed crops such as winter rape followed by soybeans or sunflowers would be desirable. However, seed yield of the second crop in a double cropping sequence must be maintained at relatively high levels to maximize oil production. When soybean planting is delayed, as in a double cropping system, seed yield usually decreases (Pendleton and Hartwig, 1973). A decrease in oil and a slight change in protein have generally been associated with late plantings

191

of soybeans (Cartter and Hartwig, 1962). Similar observations have been made in some sunflower studies although results are variable. Johnson and Jellum (1972), Unger (1980), and Unger and Thompson (1982) found that oil content of seed from late planting was generally lower than from earlierplanted sunflowers. Cooler temperatures during seed maturation have been suggested as the major environmental factor responsible for the decrease in oil percent in b o t h soybeans and sunflowers. Since this study considered on-farm production and processing of oilseed crops, a screw press for oil extraction was selected because of simplicity, ease of operation and cost relative to that of solvent extraction. Two small capacity on-farm t y p e presses are available and being used in the U.S.A. b y several researchers. Blake (1982) reported using the Simon-Rosedowns, Mini40 Press made in England, for extraction of oil from canola seed. Problems such as blockage, excessive fine materials in the oil, and excessive oil remaining in the press were greatly reduced b y a replacement set of barrels provided by the manufacturer. Oil o u t p u t was reported to be 9--10 L/h using 6--7% moisture seed. The feed rate was about 25 kg/h producing cake with less than 20% residual oil. Ramsey and Harris (1982) reported use of the Simon-Rosedowns screw press for soybean oil extraction. A b o u t 800 kg of soybeans were processed before the press operated smoothly. The choke setting of 24 produced cake with a thickness of 0.25 mm. With no pretreatment of soybeans, oil production was a b o u t 0.07 L/kg at a rate of 2.75 L/h. However, preheating to 77°C resulted in a maximum oil o u t p u t of about 0.087 L/kg. The University of Idaho seed processing system utilized a Japanese screw press (CeCoCo). In processing 11 370 kg of winter rape seed, an extraction rate of about 80% was reported b y Peterson and Thompson (1982). The power requirement for extracting the oil was 0.16 kWh/L. After production of 14 000 L of oil, the tapered end of the scroll became scored and efficiency of the press decreased. The end ring and auger were rebuilt which resulted in an overall efficiency of 85%. Ninety kilograms of sunflower seed were processed with a feeding rate of about 60 kg/h. An extraction efficiency of 70% was reported using 0.13 kWh/L. F o r t y kilograms o f raw shelled peanuts were also processed in the plant. Peanuts were run at 22, 40 and 60°C temperatures. Preheating the peanuts to 60°C increased press efficiency b y 70% over no heating. Energy consumption for processing preheated peanuts was reported to be 0.36 kWh/L. H o f m a n et al. (1981) used the CeCoCo press to extract sunflower oil. Oil delivery was about 13.25 L/h with an extraction rate of 70--75%. The extracted oil contained considerable seed particles which settled to the bott o m of the tank after a few days. Considerable variation in protein content of by-product residue due to cultivar and processing m e t h o d has been reported (Combs et al., 1963; Bowland and Standish, 1966; Woodham and Dawson, 1968). Therefore it was necessary to establish feeding values for the particular cultivars included in this study.

192 Previous vegetable oil studies that addressed the economics of on-farm production employed a variety of methods and resulted in widely differing per-unit costs of oil produced. Hofman et al. (1981) and Helgeson and Schaffner (1982) used the market price o f sunflower seed to calculate oil production costs. Lipinsky et al. (1982) reported the difference between onfarm, local market and commercial market values of sunflowers and peanuts. Due to limited research results, processing costs are usually estimated based on assumed press capabilities and related equipment. For example, Lipinsky et al. (1982) applied the manufacturer's advertised processing (40 kg/h) and extraction {90%) rates regardless o f seed type. Similarly, Claar et al. (1982) used one estimated processing cost ($0.35 per liter) for both soybeans and sunflowers. Investment costs also varied substantially among studies and depended on numerous assumptions. Lipinsky et al. (1981) reported investment costs of $22 360 for sunflowers and $25 360 for peanuts assuming that seed storage facilities and a building for the press already existed on the farm. The method of valuation of the by-product residue varied from an estimated market price (Helgeson and Schaffner, 1982) to a value based on protein content relative to 44% soybean meal (McIntosh et al., 1982) to an assumption that the value of the meal was equal to processing costs. Notwithstanding the variation in the assumptions in the above studies, per unit oil costs for small-scale, on-farm production ranged from $0.40 per liter for soybean oil (Claar et al., 1982) to $1.40 per liter for sunflower oil (Helgeson and Schaffner, 1982). METHODSANDPROCEDURES

Crop production Field plots were located on the Eastern Shore of Maryland at the Poplar Hill Research Farm, and the Wye Research and Education Center. Each o f the seven cropping systems was evaluated in 700-m 2 plots and replicated three times. Full-season crops were planted between mid-May and mid-June using conventional tillage in 1982 and 1983. Fall-planted wheat and winter rape were sown in conventionally tilled soil during October of the preceding year. Following harvest of these crops in late June, soybeans and sunflowers were planted using reduced or no-tillage practices at both locations except for the double-cropped sunflowers at Wye which were planted in conventionally tilled soil in 1983. Cultivars adapted to the Mid-Atlantic Region were used in each of the cropping systems. Standard cultural practices were used in production of each the oilseed crops.

Processing The processing plant consisted o f a Clipper Seed cleaner model M-2B

193 (0.372 kW, single-phase motor), a grain auger {0.372 kW, three-phase motor), a holding bin of about 550 kg capacity, a screw press {3.728 kW, three-phase motor) model 'Mini-40' manufactured b y Simon-Rosedowns, Hull, Great Britain, and a meal auger {0.186 kW, single-phase motor). Seeds were cleaned and then transferred by the grain auger to the holding bin which was located directly above the press and kept the press hopper continuously full b y gravity feed. Oil was allowed to settle for about one week before it was filtered b y a custom filtration unit which consisted of a recleanable pre-filter, and 40, 10, and 5-~m disposable filters. A b o u t 1300 kg each of winter rape, sunflowers, and soybeans were processed in this study. After processing of about 150 kg of peanuts, press operation was terminated due to excessive wear on the worm shaft and choke ring. Consequently, peanut residue could not be included in the feeding trials. However, sufficient oil and residue were available for energy calculations.

By-product utilization Two trials utilizing 32 finishing pigs each (eight pigs per diet) in a randomized block design were conducted to determine the growth performance supported b y screw press extraction residue from soybeans, sunflowers, and winter rape. The residues were included in standard corn-soybean meal diets so as to provide 50% of the supplemental protein. The control was commercial 44% protein content soybean meal. Early in trial 1 it became apparent that pigs fed winter rape were growing very poorly, so winter rape provided only 25% of the supplemental protein in trial 2. Each diet was fed to eight pigs {56 kg average initial weight) per pen in each trial in a standard confinement finishing facility in which each pen was equipped with a two-hole self feeder and an automatic nipple waterer. After the pigs in each pen reached an average weight of 100 kg they were fasted, weighed and shipped to the slaughter plant. Both initial weights and slaughter weights were obtained following a 12-h fast. Carcass weights were obtained as the warm carcasses moved through the kill line while length, backfat, and loin-eye area were measured on chilled carcasses. Carcass length was measured from the leading edge of the first rib to the leading edge of the aitch bone; back fat was measured at the midline opposite the first rib, last rib, and last lumbar vertebra; and loin-eye area was measured between the 10th and l l t h ribs.

Energy Energy required to produce vegetable oil fuels, and total as well as fuel energy output-to-input ratios for production of sunflowers, winter rape, soybeans, and peanuts were calculated. The total energy input included all the energy used directly for the production and processing o f oilseed crops. In-

194 direct energy inputs such as the energy embodied in the steel and tires of machinery and implements were not included in this study. Inputs include energy content of diesel fuel, fertilizers, pesticides, electricity and labor. The energy analysis of the production phase was based on standard cultural practices for those crops commercially grown in Maryland and on modified cultural practices in the native growing areas for crops not commercially grown in Maryland. Energy coefficients from Lockeretz (1980) were used to convert fertilizer rates to energy values. The specified application of chemicals were converted to energy equivalents using a list o f coefficients provided by Pimentel (1980). Diesel fuel requirements for crop production were converted to energy using a coefficient o f 38.3 MJ/L. For labor, a coefficient of 2.28 MJ/h was used to convert hours of labor to energy. Energy required to operate different components of the processing plant was measured using an energy meter. To determine the energy output, the internal energy of oil, seed, and residue for each o f the four oilseeds were measured (ASTM D240-64) using a bomb calorimeter. Since carcasses of the pigs fed winter rape residue were condemned the energy value of winter rape residue was set at zero. The total energy output-to-input ratio for vegetable oil production was determined by dividing the total energy o u t p u t by the energy input. The fuel energy output-to-input ratio was calculated by dividing fuel energy o u t p u t (oil) by fuel energy input. Economics Crop production budgets were developed for each o f the seven cropping systems for three tillage methods for a typical farm size of 240 ha as found on the Eastern Shore of Maryland. Tillage methods included conventional, reduced tillage, and no-till. Cultural practices for each cropping system and tillage method were formulated with the assistance o f University agronomists, local growers and experts on each crop in their native growing areas. For crops commercially grown in Maryland, cultural practices were those actually in use on a typical farm. For those crops not commercially grown in Maryland, cultural practices used in the native growing areas were modified, if necessary, to apply to Maryland growing conditions. Prices for inputs were an average of those obtained from local dealers. Machinery complements were developed with the assistance of agricultural engineers, growers and equipment dealers. Replacement prices were used in the calculation o f fixed costs. It was assumed that the typical farm was a corn-soybean operation with approximately 40% of the acreage devoted to double-cropped soybeans behind wheat. Calculation of fuel use per hectare allowed for the further calculation of the annual fuel requirement per farm. This figure was used in calculating production costs which depended upon the proportion of vegetable oil used in the fuel mixture. Yields used in the analysis were reported state average yields for native crops and estimated expected yields for crops not currently grown in Ma .ryland.

195 Fixed costs of processing were developed based on the calculated processing and extraction rates, an estimated 8000 h of useful life for the press and associated moving machinery, and a 15 year useful life for stationary equipment (i.e. storage bins). Variable costs consisted o f electricity and labor, where indicated. A 44% protein content soybean meal was used as b o t h the control supplement in the feeding trials and as a price standard to value the experimental residues. Residue values were calculated based on protein content and productivity as determined b y average daffy weight gain for pigs. For example, the economic value of soybean residue was based on the residue having 41.1% protein (vs. control of 44%) and an average daily gain of 0.72 kg (vs. control of 0.88 kg). The average price for 44% soybean meal on the Eastern Shore of Maryland in 1982 was approximately $310 per metric tonne, and the economic value of soybean residue was thus calculated as $233.91 per tonne. The above served as the base for formulation of variable and fixed costs of crop production and processing of the resulting oilseeds and for establishment of a credit for the by-product residue in developing a per-liter cost for producing vegetable oil. The credit for the by-product residue assumes a ready use and correspondingly reduces the cost of oil production. If the farmer faces uncertainty in the use of the residue, this will be magnified into a larger proportional uncertainty in the cost o f the oil produced. In such a case, the individual farmer must adjust the cost of oil production accordingly. RESULTS AND DISCUSSION

Crop production Yields of the oilseed crops grown in the seven cropping systems in 1982 and 1983 are shown in Table 1. In general, seed yields were lower in 1983 than in 1982. This was especially true for the full-season plantings of soybeans and peanuts. High temperatures and dry conditions o c c ~ r e d at both locations during flowering and substantially reduced yield o f these crops in 1983. Full-season sunflower yields for 1983 in Table 1 represent the mean yield o f three Interstate Seed brand cultivars that were grown at both locations. Cultivar 907 produced the highest seed yields at b o t h locations with yields o f 2214 and 2579 kg/ha at Wye and Poplar Hill, respectively. Commercial sunflower production could be easily introduced into the Mid-Atlantic Region since corn-soybean planting and harvesting equipment can be used. Peanut production, however, would require specialized harvesting and drying equipment. Soil t y p e is a concern in peanut production due to seed formation which occurs below the soil surface. The mean yield of peanuts was higher on the sandy loam soil at Poplar Hill than on the heavier silt loam soil at Wye.

196 TABLE 1 Yield o f oilseed c r o p s g r o w n in t h e seven c r o p p i n g s y s t e m s in 1 9 8 2 a n d 1 9 8 3 Cropping system

Yield ( k g ] h a ) a Wye

P o p l a r Hill

1982

1983

Mean

1982

1983

Mean

2968 2695 2289

1711 2078 b 1915

2340 2387 2103

3363 NA c 4236

2752 1953 b 1714

3058 -2975

2845 2500 604 f 2354 604 f 2811

2285 1620 2075 2321 2462 NA g

2565 2060 1340 2338 1533 --

2150 2959 NA c 1428 NA c 2762

1669 1752 NA e NA e NA e NA e

1910 2174 --

F u l l season

Soybeans Sunflowers Peanuts d Double crop

Wheat-Soybeans Wheat-Sunflowers Winter r a p e - S o y b e a n s Winter r a p e - S u n f l o w e r s

--

aAll yields c o r r e c t e d to 15% m o i s t u r e . b M e a n yield o f t h r e e cultivars in 1 9 8 3 . CNot h a r v e s t e d because o f bird d a m a g e ( s u n f l o w e r s ) or s h a t t e r i n g ( w i n t e r rape). dWhole p e a n u t s . e N o t p l a n t e d at P o p l a r Hill. f S h a t t e r i n g loss o c c u r r e d . gNot h a r v e s t e d b e c a u s e o f p o o r e m e r g e n c e .

The long growing season in the Mid-Atlantic Region permits the establishment of a summer annual crop following the harvest of a fall-planted winter annual. Soybeans following a small grain is a popular farming practice in the Mid-Atlantic Region. Over 40% of the soybean acreage in Maryland is double cropped, most of which is planted following the harvest o f wheat. Although soybean yields are usually decreased when double cropped as occurred at Poplar Hill (Table 1), the yield reduction can be small if moisture is adequate and the growing season is not reduced b y an early frost. The double-cropped soybeans following wheat at Wye, for example, produced a higher average yield than the full-season soybeans at this location (Table 1). Double-cropped sunflowers after wheat resulted in yields similar to those from full-season sunflowers. Since sunflowers mature earlier than do soybeans, and have greater drought resistance, t h e y should adapt well to double cropping in the Mid-Atlantic Region. However, some difficulty was encountered in getting good stands of sunflowers in double-cropped plantings. The potential for greatest oil yields would be from double-cropping systems utilizing winter rape and soybeans or sunflowers. Since the fall-planted winter rape matures early in the summer, double-cropped soybean and sun-

197 flower plantings can occur earlier than when these crops follow wheat. Soybean yields following winter rape were slightly lower t h a n when following wheat, but were equal to those o f full-season soybeans. Double-cropped sunflowers with winter rape showed promising yields but additional research is needed on harvesting o f winter rape.

Processing Oil extraction processing data are shown in Table 2 for the four oilseed crops. The soybean feeding rate was the highest (53.82 kg/h), partly due to the difference in the barrel design which allowed easier flow of soybeans inside the press. The feeding rate for peanuts was the lowest (18.23 kg/h) due to the size and high fiber content of the nut. Extraction efficiency for soybeans, with no pre-heating, was 32.3% compared to 72.1% for winter rape. Preheating soybeans could result in higher extraction efficiency as reported by Ramsey and Harris (1982). Oil extraction efficiency for sunflower was 65.6%, with a delivery rate of 6.54 L/h. TABLE 2 Oil extraction processing data for the four oilseed crops Crop

Oil content (%)

Feed rate (kg/h)

Oil Delivery Oil production rate extracted (L[kg) (L/h) (%)

Energy requirement (Wh]kg)

Sunflowers Winter rape Soybeans Peanuts

42 43 22 37

26.82 30.20 53.82 18.23

0.25 0.37 0.074 0.30

118.32 47.00 178.37 174.00

6.54 9.78 4.02 5.55

65.6 72.1 32.3 73.5

Energy required to produce vegetable oil fuels (Wh/kg o f oil) on the farm from sunflowers, soybeans, winter rape, and peanuts is also shown in Table 2. The highest level of energy use resulted from extracting soybean oil. This was due to the low oil content of soybeans and lowest oil extraction efficiency. High energy use for extracting peanut oil was partly due to the size and fiber c o n t e n t o f peanuts. Sunflower oil extraction required more energy t h a n did winter rape, probably due to a harder shell and higher fiber content t h a n winter rape.

By-product utilization None of the oilseed residues supported daily gains for pigs equal to those from control soybean meal. Winter rape residue supported much slower growth than did any o f the other residues (Table 3). Since the pigs fed winter rape residue grew so slowly, all these pigs were slaughtered when the first pen of pigs (those fed 25% of supplemental protein as winter rape resi-

35.6 42.2 38.9

42.6

1 2 Average

1 2 Average

1 2 Average

Overall average

Soybeans

Sunflowers

Winter r a p e

0.70

0.36 0.54 0.45 e

0.73 0.78 0.76 d

0.68 0.76 0.72 d

0.91 0.84 0.88 c

(kg)

Daily gain

68.8

128 80 104 c

64 54 59

66 60 63

49 49 49

Days t o 1 0 0 kg

2.71

1.90 2.16 2.03 c

2.67 2.96 2.82

2.78 2.85 2.82

3.35 2.96 3.16

(kg)

Daily feed

0.256

0.188 0.250 0.219

0.274 0.264 0.269

0.247 0.266 0.257

0.270 0.284 0.277

Gain/Feed

3.71

3.10 3.20 3.15 c

4.09 3.68 3.89

3.84 3.73 3.79

4.04 4.01 4.03

(cm)

Back fat

81.0

80.4 81.8 81.1

80.0 81.0 80.5

81.7 80.3 81.0

82.0 80.6 81.3

Length (cm)

30.50

27.48 32.25 29.87

28.90 29.15 29.03

29.73 29.22 29.48

31.93 35.28 33.61

Lea ( c m 2)

72.95

70.64 71.11 70.88 e

73.93 74.22 74.08 c

72.61 73.58 73.10 d

73.18 74.32 73.75 c

Dressing percentage

50.46

52.69 53.94 53.32 c

47.80 50.11 48.96

49.69 49.44 49.57

49.23 50.80 50.02

Carcass muscle percentage

aOilseed residues p r o v i d e d 50% o f t h e s u p p l e m e n t a l p r o t e i n e x c e p t t h a t w i n t e r r a p e p r o v i d e d 2 5 % o f t h e s u p p l e m e n t a l p r o t e i n in trial 2. C o n t r o l was a c o r n - s o y b e a n m e a l diet. bAll carcasses f r o m w i n t e r rape-fed pigs w e r e c o n d e m n e d d u e t o enlarged livers a n d d i s c o l o r e d k i d n e y s . c,d,eMeans in t h e same c o l u m n having differing s u p e r s c r i p t s d i f f e r at P < 0.05.

47.6 39.1 43.4

44.5 43.1 43.8

46.2 42.0 44.1

1 2 Average

Control

Gain (kg)

Trial

Treatment

Effect o f screw press oilseed residues a o n g r o w t h a n d carcass c h a r a c t e r i s t i c s b of finishing pigs

TABLE 3 OO

199 due) achieved an average weight of 100 kg. Consequently, all the winter rape-fed pigs were slaughtered together. The USDA inspector pulled all the carcasses off the rail for further examination due to the presence of "enlarged livers and discolored kidneys". Subsequently, all these carcasses were condemned due to "sulfa drug residues". The high sulfur content of glucosinolate c o m p o u n d s probably provided the sulfur in the carcass tissues since none o f these animals had received sulfa drugs. Sunflower residue tended to support better growth and carcasses than did soybean residue, while winter rape residue (Dwarf Essex cultivar) severely depressed growth, feed intake, carcass back fat, and dressing percent. Carcass muscle percent was increased b y winter rape residue, u n d o u b t e d l y due to the very lean carcasses of these slow-growing and, hence, older pigs. Furthermore, since the carcasses from pigs fed winter rape residue were condemned, there appears to be serious limitations to feeding this material to pigs. It does appear, however, that sunflower and soybean residues may show promise as a diet ingredient for finishing pigs. Additional work is needed to establish the effect of differing proportions of the diet from oilseed residues and to establish the effects o f processing parameters such as temperature on growth inhibitors or toxins in the oilseed residues.

Energy Energy inputs and outputs for all four oilseed crops using three tillage methods are presented in Table 4. Positive energy returns were obtained for all oilcrops. Energy inputs for double-cropped winter rape with soybeans and sunflowers were based on production of b o t h crops, whereas, for energy output calculation the energy value of winter rape residue was set at zero. The energy input for full-season crops ranged from 5860 MJ/ha for no-till soybeans to 15 834 MJ/ha for peanuts under conventional tillage. The total energy output-to-input ratio for full-season crops ranged from 2.62 for conventional tillage sunflowers to 7.47 for no-till soybeans. The higher energy gain for soybeans is due mostly to low energy input because nitrogen fertilizer was not used in soybean production. The fuel energy output-to-input ratio ranged from 1.43 for conventionally tilled soybeans to 7.69 for no-till peanuts. The energy input for double-cropping systems ranged from 13 061 MJ/ha for no-till winter rape/soybeans to 21 460 MJ/ha for conventionally tilled winter rape/sunflowers. The total energy output-to-input ratio for doublecropped systems ranged from 3.08 for conventionally tilled winter rape/sunflower to 5.56 for no-till winter rape/soybeans. Fuel energy output-to-input ratio ranged from 5.60 for conventionally tilled winter rape/soybeans to 13.52 for no-till winter rape/sunflowers.

Economics Crop production costs were calculated for all cropping systems and three

200 TABLE 4 Estimated energy inputs and o u t p u t s by cropping system and tillage method for onfan~ extracted vegetable oils (MJ/ha) Item

Full Season Sunflowersa

Full Season

C

R

N

C

Full Season Soybeans a C

R

N

Input Labor Fuel Fertilizer Pesticide Oil recovery Total

12 3 876 1 926 534 1 316 7664

7 2 356 1926 1 023 1 316 6628

6 1 667 1 926 945 1 316 5860

12 4059 6 295 3 079 751 14196

8 2 682 6 295 3 357 751 13093

7 1 885 6 295 3 066 751 12004

21 4965 5 206 3 800 1 842 15834

Output Oil

5534

5534

5534

15197

15197

15197

31223

38 235 43 769

38 235 43 769

38 235 43 769

22 051 37 248

22 051 37 248

22 051 37 248

29 755 60 978

Meal Total Total energy output/input

5.71

6.60

7.47

2.62

2.84

3.10

3.85

Fuel energy output/input

1.43

2.35

3.32

3.74

5.67

8.06

6.29

ac, Conventional tillage; R, Reduced tillage; N, No-till. bEnergy value of winter rape oil. TABLE 5 Estimated costs of production for the wheat-soybean double crop, 240-ha farm Item

Tillage m e t h o d s Conventional

Reduced

No-Till

Variable costs (US$) seed fertilizer lime chemicals labor fuel and lube interest

82.50 156.60 14.82 23.17 40.01 57.53 22.48

82.50 156.60 14.82 41.30 26.31 40.83 21.74

82.50 156.60 14.82 51.43 22.35 27.49 21.31

Total variable costs (US$)

397.11

384.10

376.50

Fixed costs (US$) machinery " land

193.94 148.20

197.06 148.20

162.33 148.20

Total fixed costs (US$)

342.14

345.26

310.53

Total (variable and fixed) (US$)

739.25

729.36

687.03

Credit for w h e a t c r o p (US$)

321.10

321.10

321.10

T o t a l f o r oilseed c r o p ( U S $ )

418.15

408.26

365.93

201

Peanuts a R

W i n t e r R a p e - S o y b eans a N

C

R

lS 168 206 800 842 034

16 4059 5 206 3 800 1 842 14 9 2 3

18 6 306 7 407 643 1 695 16 0 6 9

4 7 1 1 14

31 2 2 3

31 2 2 3

29755 60 9 7 8

29755 60 9 7 8

28 8 9 1 b 5534 c 38235 72 6 6 0

2 8 891 b 5534 c 38235 72 6 6 0

4 5 3 1 15

12 458 407 133 695 704

Winter Rape-S u n f l o w e r s a N

C

R

10 2 972 7 407 978 1 695 13 0 6 1

6 10 3 1 21

28 8 9 1 b 5534 c 38235 72 6 6 0

28 8 9 1 b 15197 d 22051 6 6 139

18 487 637 189 130 460

4 10 3 1 20

N

13 820 637 466 130 066

28 8 9 1 b 15197 d 22051 66 139

3 10 3 1 18

12 262 637 175 130 216

28 891 b 15197 d 22051 6 6 139

4.05

4.08

4.52

4.94

5.56

3.08

3.30

3.63

7.49

7.69

5.46

6.72

11.58

6.80

9.15

13.52

CEnergy value of s o y b e a n oil. d E n e ~ g y v a l u e of s u n f l o w e r oil.

tillage methods. The reduced tillage and no-till methods were not applied to peanuts since chemical and associated production technologies did not exist for that crop. Table 5 illustrates a crop production budget for the 240 ha, wheat-soybean double crop for the three tillage methods. The reduction in fixed costs for no-till was due to less equipment being required. For variable costs, the increased cost of chemicals was more than offset b y the savings on fuel and labor. An example of the economic analysis for the 240 ha, no-till wheat-soybean double crop is shown in Table 6. The analysis is based on the farm's need for 15 893 L of fuel per year being supplied b y fuel mixtures o f 25% vegetable oil with diesel fuel. F o r example, 31.2 ha of the crop is needed for the 25% mixture at a production cost of $11 407. Processing costs amount to $4620 while residue credit is $11 388. The net cost is $4639 for 4000 L of oil, or $1.16 per liter of oil produced. Per-liter costs of producing vegetable oil were calculated for six of the seven cropping systems, excluding peanuts. Peanuts were not included since a residue credit could not be calculated because t h e y were not included in the feeding trials. The feeding value o f winter rape residue was set at zero for the pig trials. Table 7 presents per-liter vegetable oil costs b y tillage method, cropping system, and whether processing labor was included. Comparable grades o f crude vegetable oil are available commercially. The Journal o f Commerce reported the following spot prices as of 2 December 1983: rapeseed oil, $1.14 per liter; soybean oil, $0.57 per liter; and sun-

202 TABLE 6 Economic analysis of the 240-ha farm, no-till wheat-soybean double crop

Methodology Crop production Variable costs Fixed costs Total Credit for wheat (2689 kg @ $0.11/kg 98.8 bu @ $3.25/bu) Net total for oilseed crop

Expected yields $376.50 310.53

2689 kg (98.8 bu) wheat 1680 kg (61.75 bu) soybean

$687.03

Typical corn/soybean production on a 240-ha farm using no-till requires approximately 65.43 L of diesel fuel per ha

321.10 $365.93

Processing Soybean oil content Oil extraction rate Feed rate

22% 32% 53.82 kg/h

One hectare yields 51.84 L of soybean oil and 632.3 kg of soybean residue.

Processing equipment Press Electric motor Seed cleaner Augers and Motors Filter Set-up equipment

7 800 351 1 000 1 500 1 000 2 500

Storage costs will vary according to the kind of seed processed and the amount processed. For this example, $4800 was used.

14151

By-product utilization Control soybean meal protein content Average daily weight gain for pigs Soybean residue protein content Average daily weight gain for pigs

44% 0.88 kg

Average market price of soybean meal in MD in 1982 = $308.64 per metric tonne. Thus, based on' protein content and feeding trial results, soybean residue is valued at $233.91/t.

41.1% 0.72 kg

Cost analysis 240-ha operation requires approximately 15 893 L of fuel annually.

To supply 25% of Annual fuel requirements Requires 31.2 ha of crop production, costing approximately $11 400.00 Producing approximately 4000 L of soybean oil and 49 t of soybean residue (credit for residue $11 388.56)

203 TABLE 6

(continued)

Cost Analysis Processing fixed costs Variable costs (not including labor) Total

$ 4 572.92 47.13 $ 4 620.05

Crop production + Processing -- Credit for residue

$11 407.55 4 620.05 11 388.56 $ 4 639.04

Divided by 3991.7 L implied $ 1 . 1 6 per liter bu, international corn bushel = 60 lb ~ 27.155 kg. TABLE 7 Estimated per-liter cost of vegetable oil production by cropping system, tillage method and processing labor charge for the typical 240 ha farm (25% vegetable oil-diesel fuel mixture) Tillage method

Cropping system Soybeans

Sunflowers

WheatSoybeans

WheatSunflowers

Winter rapeSoybeans

Winter rapeSunflowers

1.24 1.35 1.45

0.97 1.13 1.27

1.08 1.23 1.43

1.31 1.42 1.53

1.03 1.19 1.33

1.14 1.29 1.49

Processing labor charges excluded Conventional 1.41 Reduced 1.56 No-till 1.76

1.33 1.45 1.69

1.26 1.37 1.16

Processing labor charges included Conventional 1.52 Reduced 1.68 No-till 1.88

1.40 1.52 1.76

1.38 1.49 1.28

flower oil, $0.61 per liter. In this study, per-liter costs ranged from a high o f $1.76 for soybean oil (no-till, full-season soybeans) to a low of $0.97 for the conventionally tilled winter rape/soybeans cropping system (processing labor not included). In no instance is the final per-unit cost of vegetable oil production for the typical 240-ha farm less than the current market price for #2 diesel fuel. However, there is the fuel independence and self-sufficiency factor to consider. This 'insurance' or risk aversion factor could make vegetable oil production a viable alternative. In any case, especially in times of fuel cutoffs or shortages, or u p o n the resumption o f rapidly increasing fuel prices,

204

vegetable oil fuels may not only become price competitive with diesel fuel, but could also become the only fuel readily available. ACKNOWLEDGEMENT

Work on this project has been conducted under DOE-USDA grant number 59-2241-1-6-055-0 in cooperation with the Maryland Agricultural Experiment Station.

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