Energetics of baled alfalfa hay production in northern Greece

Agriculture Ecosystems & Environment ELSEVIER

Agriculture, Ecosystemsand Environment 49 (1994) 123-130

Energetics of baled alfalfa hay production in northern Greece C.A. Tsatsarelis a'*, D.S. K o u n d o u r a s b aDepartment of Hydraulics, Soil Science and AgriculturalEngineering, School of Agriculture, Aristotle University of ThessalonikL 54006 Thessaloniki, Greece bFarm of the Aristotle University of ThessalonikL 57001 ThessalonikL Greece

(Accepted 18 January 1994)

Abstract An energetic analysis of baled alfalfa hay production in northern Greece is presented. A total sequestered energy of 116 000 MJ ha- 1for the total production life (4 years) and the establishment was calculated. The most energy demanding operation was irrigation and the major input fuel and electric energy of the pumping system. Alfalfa hay yield was 45 900 kg ha-1 throughout the 4 year production period, i.e. 11 475 kg ha-i per year, which corresponded to a total energy output of 725 000 MJ ha- 1. A mean energy efficiency of 6.25, satisfactory for the production and irrigation system used, and productivity of 0.396 kg M J- ~was found. The interesting variation of the energy inputs, outputs, energy efficiency, productivity and intensity through the four production years are presented and discussed.

1. Introduction Alfalfa (Medicago sativa L. ), a perennial legume is used primarily as hay, silage and pasture for animal fodder but also as a source of protein. In Greece about 160 000 ha have been cultivated (about 4.4% of the agricultural land of the country), producing about 1 800 000 t of hay. Alfalfa is grown in monoculture, in rotation with grain crops and in mixtures with various species of forage grasses. It is entered into the rotation after winter cereals or before spring crops such as corn or cotton. Alfalfa is sown, managed and harvested for hay production using a variety of cultural practices that greatly influence the energetics of its production. It is established preferably in the autumn or in the spring. During the 4 or 5 years *Corresponding author.

after sowing the crop is harvested two to three times per year in unirrigated areas and five to seven times when irrigated. Various systems are used for irrigation. After harvest the hay is preserved mainly as small to medium rectangular bales (25-45 kg per bale). Net return of the crop is often poor because of low hay prices. In order to maximize this return the cost of cultivation must be minimised. To do this economic analyses must be carded out to identify where cost savings may be made without impairing yield or profitability. In addition an energy analysis can indicate ways in which energy inputs may be minimized and energy efficiency increased (Fluck and Baird, 1982) without impairing the economics of crop production. A combination of economic and energy analysis of the production system may be more comprehensive for the best management strategies.

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C.A. Tsatsarelis, D.S. Koundouras / Agriculture, Ecosystems and Environment 49 (1994) 123-130

The objectives of this study were to evaluate the energy sequestered in alfalfa baled hay production in northern Greece and to study the influence of the main inputs on energy flows and the fluctuation of the energy outputs, efficiency and productivity through the post-seeding years.

2. Materials and methods

The study was carried out in a 4.6 ha field of the Farm of the Aristotle University of Thessaloniki, during the years 1987 - 1991. The soil was clay-loam to a depth of 0-30 cm and loamy from 30-60 cm. The crop was established in the autumn of 1987 and the variety was the local Hypati. The establishment operations are shown in Table 1. Careful soil preparation was carried out including land levelling and smoothing to facilitate irrigation, forage harvesting, conditioning, baling and hay transport. For best results the land levelling-smoothing was done three times, covering the field in different directions. Field operations during the four post-seeding years were similar for each year (Table 2). At the end of the crop production life, operations were ended by loading-transporting bales from the fifth harvest. The machines used, their mass, and estimated life, are shown in Table 3. Four tractors of differTable 1 Establishment operations 1. Primary tillage with mouldboard plough at 35 cm 2. Disc harrowing 3. Land levelling-smoothing 3.1. levelling (with blade scraper) 3.2. disc harrowing 3.3. levelling (with blade scraper) 3.4. disc harrowing 3.5. final smoothing 4. Applying fertilizers (P205 = 100 kg ha - 1) 5. Seedbed preparation with rotary cultivator 6. Drilling (seed 25 kg ha- 1) 7. Rolling 8. After germination applying fertilizers (Calcium ammonium nitrate, N = 40 kg ha- t )

Table 2 Field operations for 1 year of the production life 1st harvest 1. Mowing, conditioning 2. Raking (twice) 3. Baling 4. Loading, transporting bales 5. Irrigation 2nd-4th harvests 1. Mowing, conditioning 2. Raking (once) 3. Baling 4. Loading, transporting bales 5. Irrigating 5th harvest 1. Mowing, conditioning 2. Raking (once) 3. Baling 4. Loading, transporting bales 5. Applying fertilizers P205 = 100 kg ha- 1 6. Applying pesticides (Diuron 1 kg ha- 1, Kerb 0.6 kg ha- 1)

ent power were used to match the load imposed by the machinery. A trailed mower-conditioner with cutter bar was used together with a finger wheel rake for side delivery raking, a baler producing small (about 25 kg) rectangular bales, and a tractor-mounted loader. The application of the pesticides was carried out once a year in December, and fertilizers applied after the fifth harvest also in December, applying 100 kg ha- 1 of phosphorus (P205). For irrigation, the water was pumped from a depth of 25 m with a well pump driven by a 75 kW electric motor and was distributed by a sprinkler on a traveller irdgator. About 50 m m of water was applied each time following loading-transporting the bales after each harvest (four times per year). The calculation of energy sequestered in the crop was based on the work schedule, the time needed for each operation, the machinery and the inputs (seed, fertilizers, chemicals) used. To calculate this energy, the materials used, the fuel consumption and time needed to complete each operation was recorded, during the whole life of

C.A. Tsatsarelis, D.S. Koundouras / Agriculture, Ecosystems and Environment 49 (1994) 123-130

125

Table 3 Energy content of inputs and outputs Item

Unit

Content energy (M J/unit)

Mass (kg)

Life (h)

References

Fertilizer Nitrogen Phosphorus

kg kg

Pesticides Diuron Insecticides Fuel Electric energy

kg kg kg I kWh

74.2 13.7

Lockeretz (1980) Lockeretz (1980)

418.1 274.5 363.6 47.3 12.1

Pimentel ( 1980b ) Fluck and Baird (1982) Pimentel (1980b) Fluck ( 1985 ) Jarach (1985)

Machinery Tractors Steyr MF 175 Fiat 850 Ford 3000 MF35x Plow 4 bottoms Plow 3 bottoms Disc harrow Scraper Smoother Rotary tiller Field cultivator Fertilizer distributor Driller Roller Mower-conditioner Rake Baler Bale loader Wagon Wagon Wagon Sprayer Irrigation system Hose towed traveler irrigator Pump Electric motor Wire

h h h h h h h h h h h h h h h h h h h h h h h h.m

48.5 27.1 34.5 18.6 15.8 27.4 22.3 43.9 48.5 18.3 17.7 17.1 5.7 65.1 11.4 69.6 8.6 83.9 23.4 87.1 47.4 7.1 19.1 0.092

5100 2850 3630 1950 1650 480 390 770 850 320 310 300 100 730 200 1220 150 1470 410 3050 1660 250 200

15000 15000 15000 15000 15000 2500 2500 2500 2500 2500 2500 2500 2500 1600 2500 2500 2500 2500 2500 5000 5000 5000 1500 15000

Pimentel et al. (1973); Bridges and Smith (1979), Fluck (1985) adapted Pimentel et al. (1973); Bridges and Smith (1979); Fluck (1985) adapted Pimentel et al. ( 1973); Bridges and Smith ( 1979); Fluck ( 1985 ) adapted Pimentel et al. ( 1973); Bridges and Smith ( 1979); Fluck (1985) adapted Pimentel et al. (1973); Bridges and Smith (1979); Fluck (1985) adapted Pimentel et al. ( 1973); Bridges and Smith ( 1979); Fluck (1985) adapted Pimentel et al. (1973); Bridgesand Smith (1979); Fluck ( 1985 ) adapted Pimentel et al. ( 1973 ); Bridges and Smith ( 1979); Pluck (1985) adapted Pimentel et al. ( 1973); Bridges and Smith ( 1979); Fluck ( 1985 ) adapted Pimentel et al. ( 1973); Bridges and Smith ( 1979); Fluck (1985) adapted Pimentel et al. (1973); Bridges and Smith (1979); Fluck (1985) adapted Pimentel et al. ( 1973); Bridges and Smith ( 1979); Fluck (1985) adapted Pimentel et al. ( 1973); Bridges and Smith ( 1979); Fluck ( 1985 ) adapted Pimentel et al. ( 1973); Bridge[ and Smith ( 1979); Fluck ( 1985 ) adapted Pimentel et al. ( 1973 ); Bridges and Smith ( 1979); Fluck (1985) adapted Pimentel et al. ( 1973); Bridges and Smith ( 1979); Fluck ( 1985 ) adapted Pimentel et al. ( 1973); Bridges and Smith ( 1979); Fluck (1985) adapted Pimentel et al. ( 1973 ); Bridges and Smith ( 1979); Fluck (1985) adapted Pimentelet al. (1973); Bridges and Smith (1979);Fluck ( 1985 ) adapted Pimentel et al. ( 1973); Bridges and Smith ( 1979); Fluck (1985) adapted Pimentel et al. ( 1973); Bridges and Smith ( 1979); Fluck (1985) adapted Pimentel et al. ( 1973); Bridges and Smith ( 1979); Fluck ( 1985) adapted Pimentel et al. (1973); Bridges and Smith (1979); Fluck (1985) adapted Pimentelet al. (1973); Bridges and Smith (1979); Fluck ( 1985 ) adapted

h h h ks

57.1 2.4 4.8 62.8

2000 200 400

5000 12000 12000

Pimentel et al. ( 1973); Bridges and Smith ( 1979); Fluck ( 1985 ) adapted Pimentel et al. ( 1973); Bridges and Smith ( 1979); Fluck (1985) adapted Pimentel et al. ( 1973); Bridges and Smith 91979); Fluck (1985) adapted Baldini et al. ( 1982 )

kg kg kg

28.1 15.8 18.5

Alfalfa Seed Dry hay (15% w.b.) Dry hay

Pimentel (1980b) Jarach ( 1985 ) Ebeling and Jenkins ( 1985 )

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C.A. Tsatsarelis, D.S. Koundouras / Agriculture, Ecosystems and Environment 49 (1994) 123-130

the perennial crop (5 years). Using the conversion factors of Table 3 energy inputs and outputs can be determined. Total energy embodied in machinery equalled 142.7 MJ kg- 1. This included energy for production, (86.38 MJ kg -t of mass, Pimentel et al., 1973 ), energy for repairs and maintenance, (0.55 times the energy for manufacturing, Fluck, 1985), and energy for transportation (8.8 MJ kg-x, Bridges and Smith, 1979). Taking into account the total weight and the life of machinery as used in Greece (Table 2 ), the energy required for each operation was calculated. Energy sequestered in agricultural labour was not included, although it is an input (Pimentel, 1980 a; Pellizzi, 1991 ). Several researchers assign various energy values to labour based on different methods of analysis: Stanhill (1980) assigned 0.7 MJ h - t ; Fluck (1976) 450 MJ h-I; Slesser (1973) 229 MJ h-X; Fluck and Baird (1982) 594 MJ day- 1. However, the most widely used and accepted value is 2.2 MJ h - 1 (Pimentel and Pimentel, 1979; Jarach, 1985; Galli and Spugnoli, 1985) which is based on the total energy of consumed food (3500 Kcal day-l). Unfortunately the methodological problem of energy sequestered in agricultural labour has not yet been resolved.

Table 4 Energy inputs of baled alfalfa hay production for whole production life (4 years) and for establishment Operation

Energy input MJ ha- l

Establishment Mowing-conditioning Raking Baling Bale loading-transporting Irrigation Appl. fertilizers Weed control (chemical)

Percentage

10111 4838 1737 17591 8301 67634 4216 1544

8.72 4.17 1.50 15.17 7.16 58.32 3.64 1.33

115971

I00.00

1255 414 2278 4409 664 906 184

12.41 4.10 22.53 43.61 6.57 8.96 1.82

Total

10111

100.00

Establishment 1st production year 2nd production year 3rd production year 4th production year

10111

8.72

26320 27470 26560 25510

22.69 23.69 22.90 22.00

115971

100.00

Total

Establishment Primary tillage Disc harrowing Land leveling-smoothing Appl. fertilizers Rotary tilling Drilling Rolling

3. Results

Total

Table 4 (part A) shows the energy inputs for baled alfalfa hay production. Total energy inputs were calculated to be 115 971 MJ h a - t of which 10 111 MJ ha- 1 were calculated for the establishment. The table also shows the distribution of the energy inputs for each establishment operation, and the distribution of the total sequestered energy among the establishment and the four production years. These results can be compared with Heichel and Martin (1980), who reported values for alfalfa establishment of 11 847 MJ ha -x, and for baled hay production of the second and third production years, for irrigated crops 15 102 MJ ha- x and for unirrigated crops 12 525 MJ h a - x. Larson and Fangmeir ( 1978 ) calculated total energy inputs as 295 476 MJ ha- x

for alfalfa whole production life, when ground water for irrigation was used and 17 000 MJ ha- 1, when surface water was used. Table 5 shows the quantities of input and sequestered energy into the establishment and production of the lucerne over a 4 year life. Human labour of 204 h ha-x for whole crop life was calculated. Alfalfa hay yields from each harvest and in total are shown in Table 6. Mean yield per year was found to be 11 475 kg ha-t. The corresponding energy outputs of each harvest and in total are also shown. The energy output was calculated to be 725 235 MJ ha -x, for the 4 year production life.

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127

Table 5 Distribution of sequestered energy to inputs of baled alfalfa hay production of whole production life (4 years) and establishment Input

Quantity ha- 1

Energy input MJ h- ~

Human labor Fuel Electric energy

Percentage

204.00 h 403.501 4000.00 kWh

19087 48400

16.46 41.73

Phosphorus Nitrogen

400.00kg 40.00kg

5480 2968

4.73 2.56

Herbicides Machinery Seed Wire

3.15kg 25.00kg 221.00kg

1318 24136 703 13880

1.14 20.81 0.61 11.97

115971

100.00

Fertilizers

Total

Table 6 a. Alfalfa baled hay yields (kg ha- ~) Year 1988 I st harvest 2nd harvest 3rd harvest 4th harvest 5th harvest Total

Total 1989

1990

1991

1506 3378 3090 1526 513

2305 4136 3506 2329 1143

2222 3991 3865 2245 706

1842 1577 3894 1861 266

7876 13082 14354 7960 2628

10013

13419

13029

9440

45900

b, Alfalfa hay enery outputs (MJ ha- ~) Year 1988 1st harvest 2nd harvest 3rd harvest 4th harvest 5th harvest Total

Total 1989

1990

1991

23795 53372 48822 24111 8105

36419 65349 55395 36798 18059

35108 63058 61067 35471 11154

29104 24917 61523 29405 4203

124426 206696 226807 125785 41521

158205

212020

205858

149152

725235

Mean yield per year 11475 kg ha-

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C.A. Tsatsarelis, D.S. Koundouras / Agriculture, Ecosystems and Environment 49 (1994) 123-130

Table 7 Energy productivity (kg M J - 1), energy intensity (MJ kg- 1) and energy efficiency (outputs/inputs ) Year

Hay yield (kg h a - 1) Energy inputs (MJ h a - 1) 1 Energy outputs (MJ ha -1 ) Energy productivity (kg M J - i ) Energy intensity (MJ kg -1 ) Energy efficiency

Total

1988

1989

1990

1991

10013 28848 158202 0.347 2.881 5.484

13419 29998 212020 0.447 2.335 7.068

13029 29088 205858 0.448 2.333 7.077

9440 28038 149152 0.337 2.971 5.321

45900 115971 725535 0.396 2.527 6.256

1Energy inputs of each year include also the total energy inputs for establishment ( 10111 MJ ha- 1), namely 2528 MJ ha-l.

Table 7 shows the energy productivity (the ratio of hay produced to the energy inputs in its production ) and the energy intensity (the reciprocal of energy productivity). The energy inputs from each production year as shown in Table 4 (part C ) plus the allocated energy for crop establishment (2528 MJ ha -1 per year) were calculated. Energy efficiency (ratio of the energy value of hay produced to the sequestered energy) is shown also in Table 7. Mean energy efficiency was 6.25 and 7.07 for the second and third year. It must be clarified that energy efficiency, productivity and intensity are based on only the sequestered energy (e.g. fuel, electricity, fertilizers chemicals, seed and machinery) sometimes called 'commercial energy'. Because solar energy, either as radiation or as heat was not taken into consideration, values of energy efficiency greater than one can be explained. Heichel and Martin (1980) calculated energy efficiency to be 6.98 and 7.20 for irrigated and unirrigated alfalfa hay, respectively. Larson and Fangmeir (1978), reported energy efficiency as 0.84 when ground water was used for irrigation and 14.60 when surface water was used. 4. Discussion

Irrigation consumes the greatest portion of the total sequestered energy (over 58%). From the total inputs of 67 500 MJ ha- ~for irrigation, 79% is due to electricity for the electric motor of the

pumping system and the fuel for the tractors. These high energy demands are due to the pumping system (ground water), the distribution system (sprinkler) and to the total quantity of water applied (800 mm). For other arable irrigated crops in Greece, the energy for irrigation was calculated as 48.2% of the total (about 40 000 MJ ha -1) for cotton and 35.8% (about 39 000 MJ ha- 1) for sugarbeets (Tsatsarelis, 1991, 1992). The baling of hay is an energy expensive operation, demanding over 15% of the total (about 17 500 MJ ha- 1), 65-85% of this input being due to the wire used for bale tying. Loading-transporting the bales a short distance (about 1 km) is also high energy demanding operation (7% of the total), while mowing-conditioning is less demanding. Total harvest operations from mowing to transporting the baled hay consume a high portion (28%) of the total energy inputs. Crop establishment demands a relatively high portion of the total energy (about 9%). From these demands 43% was due to fertilizers and their application and 23% for land levellingsmoothing. All other operations consumed about 1/ 3 of the total energy for establishment. Applying fertilizers throughout the whole life of the crop is almost the least energy demanding operation (only 3.5%), contrary to other arable crops. This is due to nitrogen fixing of the crop, which limits the quantities of nitrogen needed (40 kg ha- ~, once after germination). However, the quantities of phosphorus (100 kg ha-l per year) are normal for the region, but the energy content of phosphorus is only 13.7 MJ kg-1.

C.A. Tsatsarelis, D.S. Koundouras / Agriculture, Ecosystems and Environment 49 (1994) 123-130

From Table 5 it is seen that fuel and electric energy are the major energy input (58% of the total). Adding to this input the corresponding embodied energy of the machinery, the portion of the energy requirements for the machinery approaches 80% of the total. Similar results for other irrigated crops are also reported by other researchers (Larson and Fangmeir, 1978; Scott and Krummel, 1980; Tsatsarelis 1992). Therefore, machinery management, including selection, use and maintenance, is of great importance to obtain a high energy productivity. Wire for tying the bales was, unexpectedly energy expensive, demanding about 12% of the total inputs, due to the high quantities needed (221 kg ha -1 ) and to the high energy content (62.8 MJ kg-~). The variation of energy productivity, intensity and efficiency through the production life is very interesting (Table 7 ). In the second and third production year energy efficiency and the other two indices were higher. This is due to higher yields and consequently to higher energy outputs (Table 6), but also to similar, energy inputs during the four production years (Tables 4C and 7 ). The fourth production year from the point of energy efficiency and productivity was more energy expensive than the other years and is thus under consideration. If the life of the crop was ended after the third year, energy efficiency would be 6.37, productivity 0.403 kg MJ-1 and intensity 2.481 MJ kg- 1. Energy efficiency of alfalfa hay, compared with energy efficiencies of other irrigated crops that use the same irrigation system, was higher (sugarbeets: 1.42-2.25, cotton: 0.19-0.22, Tsatsarelis, 1992, 1991 ). This is due, mainly, to very low quantities of nitrogen needed and to higher output energy. The energy efficiency could be better if yields were higher and the inputs for crop production were maintained. In many regions of the country mean yields of 15 000 kg ha- 1are frequent. From Table 6 it is seen that yields of the fourth and the fifth harvest, each year, are very low. Lower also, compared with other regions of the country, are the yields of the second and third harvest which

129

is mainly due to aridity of the region and the limited water supply. Supplying 75% higher quantities of water to the crop, is estimated to result in hay yields 35% higher for the second harvest and 50% to maximum, for the third, fourth and fifth, these results were obtained in previous years when higher quantities of water were supplied. The corresponding hay yields and energy outputs with higher water supply are shown in Table 8. The increased hay yields do not result in increased energy efficiency, because of higher energy inputs. So energy efficiency becomes 5.966 instead of 6.250. Energy productivity and intensity were estimated as 0.378 and 2.648 instead of 0.396 and 2.527 when less water was supplied. The energy efficiency can be higher for the same quantities of water, when surface water and surface distribution are used. In this case hay yields remain as calculated but energy inputs are reduced to 48 337 MJ ha -1 and energy efficiency was calculated as 15.004. A better energy efficiency could also be achieved by reducing energy inputs but it is considered that in the case studied energy inputs were as low as possible. Human labour of 204 h ha-1 is needed (Table 5 ) for all operations during the crop life. Of this 28 h ha- 1 is needed for establishment and about 44 h ha- ~for each production year, 62% of which is needed for bale loading-transporting.

Table 8 Alfalfa baled hay yields (kg h a - 1) and corresponding energy outputs (MJ h a - ~) with increased irrigation water, for whole production life Yield (kgha -~)

Energy output ( M J h a -~)

I st harvest 2nd harvest 3rd harvest 4th harvest 5th harvest

7876 17660 21532 11940 3942

124426 279028 340190 188652 62284

Total

62950

994580

Mean yield per year 15537 kg ha- 1. Mean increase in yield and output 37.1%.

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5. Conclusions The main conclusions of this study may be summarised as follows: ( 1 ) Energy sequestered in baled alfalfa hay was calculated as 116 000 MJ ha-1, for the whole production life (4 years) and the establishment, giving a mean input per year of about 29 000 MJ ha -1. (2) Total hay yield was found to be 45 900 kg ha-1 for the 4 years after sowing giving a mean yield per year of 11 475 kg ha- 1. (3) Energy outputs were calculated for the whole crop life as 725 000 MJ ha -1 with higher outputs calculated for the second and third production years. (4) The mean energy efficiency and productivity was calculated as 6.25 kg MJ- 1 and 0.396 kg M J- 1, respectively. (5) Higher energy efficiency and productivity were calculated for the second and third years of production. (6) Irrigation was the operation with the highest energy demands being up to 58% of the total. (7) Fuel, electric energy and the embodied energy of the machinery, were the major energy inputs representing 79% of the total inputs.

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