Analyzing the energy balances of double-cropped cereals in an arid region

Zahedi, Mortaza; Mondani, Farzad; Eshghizadeh, Hamid Reza Article Analyzing the energy balances of double-cropped cereals in an arid region Energy Reports Provided in Cooperation with: Elsevier Suggested Citation: Zahedi, Mortaza; Mondani, Farzad; Eshghizadeh, Hamid Reza (2015) : Analyzing the energy balances of double-cropped cereals in an arid region, Energy Reports, ISSN 2352-4847, Elsevier, Amsterdam, Vol. 1, pp. 43-49, https://doi.org/10.1016/j.egyr.2014.11.001 This Version is available at: https://hdl.handle.net/10419/187803 Standard-Nutzungsbedingungen: Die Dokumente auf EconStor dürfen zu eigenen wissenschaftlichen Zwecken und zum Privatgebrauch gespeichert und kopiert werden. Sie dürfen die Dokumente nicht für öffentliche oder kommerzielle Zwecke vervielfältigen, öffentlich ausstellen, öffentlich zugänglich machen, vertreiben oder anderweitig nutzen. Sofern die Verfasser die Dokumente unter Open-Content-Lizenzen (insbesondere CC-Lizenzen) zur Verfügung gestellt haben sollten, gelten abweichend von diesen Nutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte. Terms of use: Documents in EconStor may be saved and copied for your personal and scholarly purposes. You are not to copy documents for public or commercial purposes, to exhibit the documents publicly, to make them publicly available on the internet, or to distribute or otherwise use the documents in public. If the documents have been made available under an Open Content Licence (especially Creative Commons Licences), you may exercise further usage rights as specified in the indicated licence. https://creativecommons.org/licenses/by-nc-nd/4.0/ Energy Reports 1 (2015) 43–49 Contents lists available at ScienceDirect Energy Reports journal homepage: www.elsevier.com/locate/egyr Analyzing the energy balances of double-cropped cereals in an arid region Mortaza Zahedia, Farzad Mondanib,∗, Hamid Reza Eshghizadeha aDepartment of Agronomy and Plant Breeding, Faculty of Agriculture, Isfahan University of Technology, Isfahan, Iran bDepartment of Agronomy and Plant Breeding, Campus of Agriculture and Natural Resources, Razi University, Kermanshah, Iran article info Article history: Received 28 September 2014 Received in revised form 19 November 2014 Accepted 22 November 2014 Available online 21 January 2015 Keywords: Cereal Double cropping Environmental health Energy efficiency Productivity Specific energy abstract Efficient use of energy in agroecosystems will reduce environmental problems, prevent destruction of natural resources and serve to promote sustainable agriculture as an economical production system. The aim of this study was to investigate the energy use efficiency in four double cropping systems including: wheat–silage corn (W–SC), barely–silage corn (B–SC), barely–grain corn (B–GC) and barely–rice (B–R) in the arid regions of Isfahan province, Iran. Data used in this study were collected from 73, 45, 38, 18, 18 wheat, barley, silage corn, grain corn and rice farms, respectively, personal interview using semistructured questionnaire during 2010. The results indicated that the total energy consumed were 140,422, 128,979, 121,360 and 172,962 MJ ha−1for the W–SC, the B–GC, the B–SC and the B–R cropping systems, respectively. The share of diesel fuel by 43.36% (W–SC), 43.93% (B–GC), 42.82% (B–SC) and 49.40 % (B–R) was the highest input. This was followed by fertilizer (W–SC: 24.70%, B–GC: 25.12%, B–SC: 27.05 and B–R: 16.11) and water (W–SC: 10.54%, B–GC: 11.76%, B–SC: 10.73 and B–R: 13.85), respectively. The energy use efficiency was found as 1.70 for W–SC, 1.65 for B–GC, 1.64 for B–SC and 1.03 for B–R double cropping systems, respectively. According to the research results the W–SC, B–SC, B–GC and B–R double cropping systems were more efficient in terms of energy, respectively. ©2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 1. Introduction Energy is a critical input in agricultural production systems. The energy used in agriculture was directly related to environmental factors such as soil and climatic conditions, amount of inputs and techniques employed in production (Esengun et al., 2007). The link between agriculture and energy is very close. Agriculture itself uses energy and is also a supplier of energy in the form of bio-energy (Alam et al., 2005). Energy used in agriculture has developed in response to increasing populations, the limited supply of arable land and a desire for increasing standards of living (Shahan et al., 2008). All inputs and outputs of a cropping system can be expressed in terms of energy. Hence, energy input and output are essential factors for determining energy efficiency and the environmental impact of crop production. However, energy utilization and output differs widely among crops, production systems and management intensity (Rathke et al., 2007). ∗Corresponding author. E-mail address: [email protected] (F. Mondani). Changes in farm technology over time have increased the amount of energy used in crop production (Rathke and Diepenbrock, 2006). The predominant feature for increasing crop production is the use of a large amount of energy either directly or indirectly in the form of fuel, electricity and fertilizers (HajSeyedHadi et al., 2009). Environmental problems such as those associated with soil, water pollution and CO2and N2O emissions that contribute to global warming are related to intensive use of energy. Energy analysis of agricultural ecosystems seems to be a promising approach to investigate and assess efficiency, environmental problems and their relations to sustainability (Khan et al., 2007). It is also used to compare different production systems (GhasemiMobtaker et al., 2010). Efficient use of energy in agriculture will minimize environmental problems, prevent destruction of natural resources and serve to promote sustainable agriculture as an economical production system (Esengun et al.,2007;Erdal et al., 2007). The relation of energy input and energy output in the agroecosystems have been investigated by many researchers for many crops such as sugar beet (Asgharipour et al.,2012;Yousefi et al., 2014), tomato (Rezvani Moghaddam et al., 2011), pulses (Koocheki et al., 2011) and cotton (Zahedi et al., 2014). In the Mediterranean regions such as Isfahan province when irrigation water is available, the double cropping systems can be http://dx.doi.org/10.1016/j.egyr.2014.11.001 2352-4847/©2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4. 0/). 44 M. Zahedi et al. / Energy Reports 1 (2015) 43–49 improved income of farmers and might be helped to sustainability of agricultural activities. Double cereal systems differences in management practices such as farm technology, tillage and intensity, have considerable effects on energy input and efficiency of crop production systems. Browning (Browning, 2011) indicated that soybean double-cropped after barley has the potential to yield equal to or greater than full-season soybean or doublecropped soybean following wheat, but its relative yield is very dependent on growing conditions in Virginia and the Mid-Atlantic, USA. Therefore, aims of this study were (i) to determine the total amount of input–output energy used in four double cropping systems (wheat–silage corn, barely–silage corn, barely–grain corn and barely–rice), (ii) to determine energy use efficiency, (iii) to determine the best double-cropped cereals based on energy efficiency, in Isfahan province of Iran as a Mediterranean region. 2. Material and methods The present study was conducted in Isfahan province located in central Iran (geographical coordinates 30°43′and 34°27′N and 49°36′and 55°31′E). The total area of the province is 105,937 km2 and the total farming area is 360,181 km2, of that the share of cereal (wheat (Triticum aestivum), barley (Hordeum vulgare), rice (Oryza sativa) and corn (Zea mays)) is about 57% (206,172 ha). Four double cropping systems consist: wheat–silage corn (W–SC), barely–silage corn (B–SC), barely–grain corn (B–GC) and barely–rice (B–R) were determining energy use, to investigate the energy use efficiency, and to make an economical analysis. Information was collected from cereal farmers using a face-to-face questionnaire during 2010. In addition to the data obtained by surveys, previous studies of related organizations such as the Ministry of Agriculture of Iran (MAJ) (Browning, 2011) were also used for this research. The number of operations involved in cereal rotation production systems and their energy requirements influence the final energy balance. The sample size was calculated using the Neyman method (Newbold, 1994): n=N×S2 (N−1)S2 X+S2(1) where: n, is the required sample size; N, is number of farmers in the target population; Sis standard deviation, SX, is standard deviation of sample mean (SX=d/z), d, is the permissible error in the sample size, and was determined as 10% of the mean for a 95% confidence interval and zis the reliability coefficient (1.96, which represents 95% reliability). Based on this calculation the size of 73 for wheat, 45 for barley, 38 for silage corn, 18 for grain corn, and 18 for rice farms were considered as sampling sizes. Energy efficiency of the agricultural system has been evaluated by the energy ratio between output and input. Human labor, machinery, diesel oil, fertilizer, pesticides and seed amounts and output yield values of cereal production systems have been used to estimate energy ratios (Alam et al., 2005). Energy equivalents shown in Table 1 were used for estimations (Haj-SeyedHadi et al., 2009;Khan et al.,2007;Erdal et al.,2007). The sources of mechanical energy used on the selected farms included tractors and diesel fuel. Mechanical energy was computed on the basis of total fuel consumption (l ha−1) in different operations. Therefore, the energy consumed was calculated using conversion factors and expressed in MJ ha1(Tsatsarelis, 1991). The energy of a tractor and its equipment reveals the amount of energy needed for unit weights and calculates repair and care energy, transport energy, total machine weight and average economic life. Based on energy equivalents of inputs and outputs (Table 1), energy use efficiency, energy productivity, specific energy, energy intensiveness and net energy were Table 1 Energy equivalent of inputs and outputs in agricultural production. Particulars Unit Energy equivalent (MJ unit−1) A. Inputs 1. Human labor h 1.95 2. Machinery h 62.7 3. Diesel fuel l 50.23 4. Chemical fertilizers (a) Nitrogen (N) kg 75.46 (b) Phosphate (P2O5) kg 13.07 (c) Potassium (K2O) kg 11.15 (d) Micro kg 120.00 5. Manure kg 0.30 6. Chemicals (a) Herbicides kg or l 238.3 (b) Pesticide l 101.2 (c) Fungicide kg 181.9 7. Electricity kWh 3.6 8. Water for irrigation m31.02 9. Seeds (wheat) kg 20.10 10. Seeds (barely) kg 14.7 11. Seeds (corn) kg 14.7 12. Seeds (rice) kg 14.7 B. Outputs 1. Wheat grain yield kg 14.7 2. Wheat straw yield kg 2.25 3. Barely grain yield kg 14.7 4. Barely straw yield kg 2.25 5. Corn grain yield kg 14.7 6. Corn straw yield kg 2.25 7. Rice grain yield kg 14.7 8. Rice straw yield kg 2.25 calculated by the following equations (Demircan et al., 2006): Energy use efficiency =Energy output (MJ ha−1) Energy input (MJ ha−1)(2) Energy productivity =crops output (Kg ha−1) Energy input (MJ ha−1)(3) Specific energy =Energy input (MJ ha−1) crops output (Kg ha−1)(4) Energy intensiveness =Energy input (MJ ha−1) cost of cultivation ($ ha−1)(5) Net energy =Energy output (MJ ha−1) −Energy input (MJ ha−1). (6) Indirect energy included energy embodied in seeds, chemical fertilizers, herbicide, pesticide, fungicide, farmyard manure and machinery; while direct energy was evaluated in terms of human labor, diesel, electricity and water for irrigation used in the cereal rotation production systems. Non-renewable energy included diesel, electricity, chemical fertilizers, herbicides; pesticides, fungicides and machinery; and renewable energy consisted of human labor, farmyard, seeds and water for irrigation, farmyard manure. 3. Results and discussion 3.1. Structures of farms The average field size was about 20.2 ha for wheat, 14.4 ha for barley, 5.5 ha for silage corn, 2.6 ha grain corn, and 0.5 ha for rice in according to information provided by the survey. Planting areas for wheat, barley, rice and grain corn were 139,426, 47,288, 17,452 and 2006 ha, and the production of these crops was 561,652, 177,893, 99,407 and 13,838 tons, respectively. All necessary cultural practices such as soil tillage, seedbed preparation, planting M. Zahedi et al. / Energy Reports 1 (2015) 43–49 45 Table 2 Management practices of wheat, barley, rice and corn for grain and silage. Operations Wheat Barely Seed corn Seed silage Rice Millet Names of varieties Rosahan, Kavir, Pishtaz, Native cultivars Valphajr, Reyhan, Native cultivars SC704, SC700 SC704, SC700 Native cultivars (Sorkhe, Gerdesefid) Jam, Kermanshahi, Karaj 12-60-31 Land preparation tractor used: 285 MF 75 hp Moldboard plow, Disc harrows, Land leveler Moldboard plow, Disc harrows, Land leveler Moldboard plow, Disc harrows, Land leveler Chisel, Disc harrows Moldboard plow, Disc harrows Chisel–Disc harrows Land preparation period Late October–Mid September Early October–Early September Mid May Late June Early June June Average tilling number 2.2 2.2 2.2 1.2 2.2 1.0 Planting period Early December–Late September Mid October–Mid September Mid June Early July Late June June Fertilization period (Before planting) Late October–Mid September Early October–Early September Mid May Late June Early June June Fertilization period (Top dressing) Mid March–Late March Mid March–Late March Late July–Early August Early August – – Average number of fertilization 2.2 1.2 1.5 1.5 1.2 1.0 Irrigation period September–Early June September–Early June June–Late September June–Late September June–Late September June–September Average number of irrigation 12.5 11.5 7.2 6 – 3 Spraying period May–June May–June Late July–Early August – August July Average number of spraying 1 0.6 1.8 0.8 1 1 Harvesting period Late June Late June Late September Late September Late September November Table 3 Energy consumption and energy input–output relationship of wheat. Energy Quantity per unit area (ha) Energy equivalent (MJ unit−1) Total energy equivalent (MJ) Percentage of total energy input (%) Input Human labor (h) 495.4 1.95 966.0 1.4 Machinery (h) 52.0 62.70 3260.5 4.8 Diesel fuel (l) 579.3 50.23 29100.8 42.7 Nitrogen (kg) 161.9 75.46 12221.9 17.9 Phosphate (P2O5) (kg) 137.4 13.07 1796.4 2.6 Potassium (K2O) (kg) 106.2 11.15 1184.7 1.7 Manure (kg) 6400 0.30 1920.0 2.8 Micro (kg or l) 4.6 120.0 558.3 0.8 Treflan (l) 3.9 238.32 928.2 1.4 Pesticide (Diazinon) (l) 1.2 101.20 121.4 0.2 Fungicide (Carboxin) (kg) 2.0 216.90 432.0 0.63 Electricity (kWh) 800.0 3.60 2880.0 4.2 Water for irrigation (m−3) 6700.0 1.02 6834.0 10.03 Seed (kg) 293.5 20.1 5899.4 8.7 Total energy input (MJ) 68104.1 100.00 Outputs Wheat grain yield (kg) 6700.50 14.90 98497.3 90.5 Bean straw yield (kg) 4600.30 2.25 10350.7 9.5 Total energy output (MJ) 108848.0 Energy efficiency 1.6 methods, planting and harvest period were determined and presented in Table 2. Our results also indicated that about 84% and 16% of the total planting area in cereal production system was irrigated farms and dryland farms, respectively. All farms were in personal possession. The method and timing of management practices for different crops during the growing season are shown in Table 2. 3.2. Analysis of input–output energy Total input energy consumed for cereal crops with respect to different input and agronomical practices are shown in Tables 3–7. Most of the input energy for wheat production was related to diesel fuel, nitrogen and water for irrigation by 42.7, 17.9 and 10.03%, respectively. The same trend was observed for barely, grain and silage corn but it was different in rice as inputs of water for irrigation (15.7%) and electricity (10.4%) were higher than nitrogen. So, the share of diesel fuel was the highest energy input for all crops. Similar result have been observed for wheat (Canakci et al.,2005; Ghorbani et al.,2011;Khan et al.,2009), barely (Canakci et al., 2005;Khan et al.,2009), corn (Canakci et al., 2005), rice (Khan et al., 2009) and other irrigated crops such canola and sunflower (SheikhDavoodi and Houshyar, 2009) despite the differences in the arrangement in the first second or third category. Given the predominant role of diesel fuel, irrigation and fertilization in accounting for sequestered energy in agricultural systems in this 46 M. Zahedi et al. / Energy Reports 1 (2015) 43–49 Table 4 Energy consumption and energy input–output relationship of barely. Energy Quantity per unit area (ha) Energy equivalent (MJ unit−1) Total energy equivalent (MJ) Percentage of total energy input (%) Input Human labor (h) 350.3 1.95 683.1 1.2 Machinery (h) 47.3 62.70 2965.9 5.1 Diesel fuel (l) 486.9 50.23 24457.7 41.4 Nitrogen (kg) 183.4 75.46 13841.8 23.4 Phosphate (P2O5) (kg) 121.3 13.07 1584.8 2.7 Potassium (K2O) (kg) 91.7 11.15 1022.1 1.7 Manure (kg) 2600.0 0.30 780.0 1.3 Micro (kg or l) 1.4 120.0 162.6 0.3 Treflan (l) 3.1 238.3 737.8 1.3 Pesticide (Diazinon) (l) 1.7 101.20 167.9 01.3 Fungicide (Carboxin) (kg) 2.7 216.00 578.1 0.9 Electricity (kWh) 700 3.60 2520.0 4.3 Water for irrigation (m−3) 6000.0 1.02 6120.0 10.4 Seed (kg) 232.7 14.70 3420.7 5.8 Total energy input (MJ) 59042.5 100.00 Outputs Barely grain yield (kg) 5081.6 14.07 74699.5 88.5 Barely straw yield (kg) 4300.5 2.25 9676.1 11.5 Total energy output (MJ) 84375.6 Energy efficiency 1.43 Table 5 Energy consumption and energy input–output relationship of grain corn. Energy Quantity per unit area (ha) Energy equivalent (MJ unit−1) Total energy equivalent (MJ) Percentage of total energy input (%) Input Human labor (h) 378.9 1.95 756.6 1.1 Machinery (h) 33.4 62.70 2069.1 3.0 Diesel fuel (l) 641.2 50.23 32205.7 46.1 Nitrogen (kg) 173.1 75.46 13057.7 18.7 Phosphate (P2O5) (kg) 90.5 13.07 1182.4 1.7 Potassium (K2O) (kg) 57.5 11.15 641.4 0.9 Manure (kg) 8125.0 0.30 2437.5 3.5 Micro (kg or l) 7.6 120.0 918.6 1.3 Treflan (l) 5.1 238.32 1213.8 1.7 Pesticide (Diazinon) (l) 1.6 101.20 161.9 0.2 Fungicide (Carboxin) (kg) 3.1 216.90 669.6 1.0 Electricity (kWh) 1330.0 3.60 4788.0 6.8 Water for irrigation (m−3) 8870.0 1.02 9047.4 12.9 Seed (kg) 51.7 14.7 759.9 1.1 Total energy input (MJ) 69936.7 100.00 Outputs Corn grain yield (kg) 8880.50 14.7 129360.0 100.0 Total energy output (MJ) 129360.0 Energy efficiency 1.85 region, it is evident that any attempt to reduce energy input should begin by finding to reduce these inputs. The machinery management and using efficient equipment to reduce direct use of diesel fuel energy, increasing nitrogen use efficiency (due to mainly embodied energy of nitrogen, 75.46 MJ kg−1) with different approaches such as application of nitrogen only base on the soil analysis and using nitrogen in several time as topdressing. In this region, average of irrigation water that used for successful wheat, barley, rice, grain and silage corn production are around 6700, 6000, 17,500, 8870 and 7821 m3per each hectare, respectively. So, reduction of water irrigation may be achieved by reducing the amount of water supplied as effective use of water, deficit irrigation strategy, using, where possible, alternative irrigation systems or improving irrigation and pumping efficiency (Tsatsarelis, 1991). The total energy input of 140,422 MJ ha−1(W: 68,104 MJ ha−1+ SC: 72,318 MJ ha−1), 128,979 MJ ha−1(B: 59,043 MJ ha−1+GC: 69,937 MJ ha−1BSC), 121,360 MJ ha−1(B: 59,043 MJ ha−1+SC: 72,318 MJ ha−1) and 172,962 MJ ha−1(B: 59,043 MJ ha−1+R: 113,920 MJ ha−1) were required for different double cropping systems, respectively (Table 8). In literature, the results showed that total energy input were 51,040 MJ ha−1for full-season wheat and 44,866 for full-season barley (Sahabi et al., 2012), and 72,743 for full-season corn (Safa et al., 2010), respectively. Grain and straw yield of crops are shown in Tables 3–7. Total energy output per hectare was 108,848, 84,375.6, 129,360, 130,981.5, and 93,690.3 MJ ha−1in wheat, barley, grain corn, silage corn and rice production systems, respectively. The highest output energy (239,829 MJ ha−1) was obtained in W–SC and the lowest (178,066 MJ ha−1) was in the B–R double-cropped system. Energy consumption and energy input–output in different double-cropped cereals are shown in Table 9. Energy use efficiency in wheat, barley, grain corn, silage corn, and rice was 1.6, 1.43, 1.85, 1.81 and 0.82, respectively. The doublecropped cereals, W–SC had the highest energy efficiency (1.70) and barely–rice had the lowest (1.03). The research results were consistent with finding reported by other authors, such as: 1.70 for wheat and 1.83 for barley in irrigated farming in northeast of Iran (Sahabi et al., 2012) and 2.8 for wheat and 3.8 for maize in Antalya region, M. Zahedi et al. / Energy Reports 1 (2015) 43–49 47 Table 6 Energy consumption and energy input–output relationship of silage corn. Energy Quantity per unit area (ha) Energy equivalent (MJ unit−1) Total energy equivalent (MJ) Percentage of total energy input (%) Input Human labor (h) 489.5 1.95 954.5 1.3 Machinery (h) 43.1 62.70 2698.1 3.7 Diesel fuel (l) 633.1 50.23 31798.8 44.0 Nitrogen (kg) 214.4 75.46 16181.7 22.4 Phosphate (P2O5) (kg) 90.5 13.07 1182.4 1.6 Potassium (K2O) (kg) 57.5 11.15 641.4 0.9 Manure (kg) 8125.0 0.30 2473.5 3.4 Micro (kg or l) 7.6 120.0 918.6 1.3 Treflan (l) 5.1 238.32 1213.8 1.7 Pesticide (Diazinon) (l) 1.6 101.20 161.9 0.2 Fungicide (Carboxin) (kg) 3.1 216.90 669.6 0.9 Electricity (kWh) 1230.0 3.60 4428.0 6.1 Water for irrigation (m−3) 7821.0 1.02 7977.4 11.1 Seed (kg) 71.7 14.7 1054.0 1.5 Total energy input (MJ) 72317.7 100.00 Outputs Corn straw yield (kg) 58214.30 2.25 130981.5 100.0 Total energy output (MJ) 130981.5 Energy efficiency 1.81 Table 7 Energy consumption and energy input–output relationship of rice. Energy Quantity per unit area (ha) Energy equivalent (MJ unit−1) Total energy equivalent (MJ) Percentage of total energy input (%) Input Human labor (h) 881.3 1.95 1718.5 1.5 Machinery (h) 58.1 62.70 3642.9 3.2 Diesel fuel (l) 1214.9 50.23 61024.9 53.6 Nitrogen (kg) 116.0 75.46 8750.8 7.7 Phosphate (P2O5) (kg) 91.4 13.07 1195.3 1.1 Potassium (K2O) (kg) 56.2 11.15 627.2 0.5 Manure (kg) 4123.0 0.30 1236.9 1.1 Micro (kg or l) 5.6 120.0 678.6 0.6 Treflan (l) 4.9 238.32 1166.2 1.1 Pesticide (Diazinon) (l) 1.3 101.20 131.6 0.1 Fungicide (Carboxin) (kg) 1.1 216.90 237.6 0.2 Electricity (kWh) 3300.0 3.60 11880.0 10.4 Water for irrigation (m−3) 17500.0 1.02 17850.0 15.7 Seed (kg) 257.1 14.7 3779.4 3.3 Total energy input (MJ) 113919.7 100.00 Outputs Rice grain yield (kg) 5920.40 14.7 87029.9 92.9 Rice straw yield (kg) 2960.20 2.25 6660.5 7.1 Total energy output (MJ) 93690.3 Energy efficiency 0.82 Table 8 Total energy input in the form of direct, indirect, renewable energy for different double cropping systems. Source Wheat–Silage corn Barely–Seed corn Barely–Silage corn Barely–Rice W SC Total B GC Total B SC Total B R Total Direct energya39,780.8 45,158.8 84,939.6 33,780.7 46,797.7 80,578.4 33,780.7 45,158.8 78,939.5 33,780.7 92,473.5 126,254.2 Indirect energyb28,323.2 27,159.0 55,482.2 25,261.7 23,139.0 48,400.7 25,261.7 27,159.0 52,420.7 25,261.7 21,446.3 46,708 Renewable energyc15,619.3 12,423.4 28,042.7 11,003.7 13,001.5 24,005.2 11,003.7 12,423.4 23,427.1 11,003.7 24,584.8 35,588.5 Non-renewable energyd 39,780.8 59,894.3 99,675.1 48,038.7 56,935.2 104,973.9 48,038.7 59,894.3 107,933 48,038.7 89,334.9 137,373.6 Total energy input 68,104 72,318 140,422 59,043 69,937 128,979 59,043 72,318 131,360 59,043 113,920 172,962 aIndicates human labor, diesel, electricity and water. bIndicates seeds, chemical fertilizers (NPK), herbicide (Treflan and Basagran), pesticide (Diazinon), fungicide (Carboxin) and machinery. cIndicates human labor, seeds and water. dIndicates diesel, electricity, chemical fertilizers (NPK), herbicide (Treflan and Basagran), pesticide (Diazinon), fungicide (Carboxin) and machinery. Turkey (Canakci et al., 2005) under the conventional farming system, respectively. It seems that suitable condition as climate and soil properties is one of the important reasons for more efficient agriculture systems in Turkey in comparison with Iran in these reports. In wheat, barley and rice farms overall energy input–output ratio is very low compared to farms at Australia (Khan et al., 2009), where it was 9.21, 8.21 and 6.70, respectively. In case of wheat, energy use efficiency in other parts of the world as well as New Zealand (Barber, 2004), Turkey (Canakci et al., 2005), India 48 M. Zahedi et al. / Energy Reports 1 (2015) 43–49 Table 9 Energy input–output ratio in four double cropping systems consist: wheat–silage corn (W–SC), barely–silage corn (B–SC), barely–grain corn (B–GC) and barely–rice (B–R). Source Unit Wheat–Silage corn Barely–Grain corn Barely–Silage corn Barely–Rice W SC Total B GC Total B SC Total B R Total Total energy input MJ ha−168,104 72,318 140,422 59,043 69,937 128,979 59,043 72,318 131,360 59,043 113,920 172,962 Total energy output MJ ha−1108,848 130,981 239,829 84,376 129,360 213,736 84,376 130,982 215,357 84,376 93,690 178,066 Energy efficiency – 1.6 1.81 1.70 1.43 1.85 1.66 1.43 1.81 1.64 1.43 0.82 1.03 Energy intensiveness MJ $−136.5 39.5 76 39.3 38.7 78 39.3 39.5 78.8 39.3 35.7 75 Specific energy MJ kg−10.1 1.2 1.3 11.6 7.9 19.5 11.6 1.2 12.8 11.6 0.1 11.7 Energy productivity kg MJ−10.098 0.804 0.46 0.086 0.125 0.107 0.086 0.804 0.481 0.086 0.051 0.063 Net energy MJ ha−140,744.0 58,663.8 99,407.8 25,333.2 59,423.3 84,756.5 25,333.2 58,663.8 83,997 25,333.2 −20,229.4 5103.8 Table 10 Energy consumption (total energy equivalent (MJ ha−1)) and energy input–output relationship in different double cropping systems. Source Wheat–Silage corn Barely–Seed corn Barely–Silage corn Barely–Rice W SC Total B GC Total B SC Total B R Total Human labor 966 954 1,920 683 757 1,440 683 955 1,638 683 1,719 2,402 Machinery 3,260 2,698 5,959 2,966 2,069 5,035 2,966 2,698 5,664 2,966 3,643 6,609 Diesel fuel 29,101 31,799 60,900 24,458 32,206 56,663 24,458 31,799 56,257 24,458 61,025 85,483 Fertilizers 15,761 18,924 34,685 16,611 15,800 32,411 16,611 18,924 35,535 16,611 11,252 27,863 Chemicals 1,482 2,045 3,527 1,484 2,045 3,529 1,484 2,045 3,529 1,484 1,535 3,019 Manure 1,920 2,473 4,393 780 2,438 3,218 780 2,474 3,254 780 1,237 2,017 Electricity 2,880 4,428 7,308 2,520 4,788 7,308 2,520 4,428 6,948 2,520 11,880 14,400 Water 6,834 7,977 14,811 6,120 9,047 15,167 6,120 7,977 14,097 6,120 17,850 23,970 Seed 5,899 1,054 6,953 3,421 760 4,181 3,421 1,054 4,475 3,421 3,779 7,200 Total energy input 68,104 72,318 140,422 59,043 69,937 128,979 59,043 72,318 131,360 59,043 113,920 172,962 Total energy output 108,848 130,981 239,829 84,376 129,360 213,736 84,376 130,982 215,357 84,376 93,690 178,066 Energy efficiency 1.6 1.81 1.70 1.43 1.85 1.65 1.43 1.81 1.64 1.43 0.82 1.03 (Singh et al., 2002) and Pakistan (Khan et al., 2007), was 2.9, 2.8, 3.2, 2.5 and 3.46, respectively, which is greater than the value obtained in this study. The main reason for this can be the higher consumption of fossil fuels and fertilizer inputs at low cost and low efficiency of the equipment used in this region. 3.3. Energy intensiveness, productivity, specific and net energy The results showed that acquired amounts of energy intensity had little difference in the various double-cropped systems as is summarized in Table 8. Average of energy productivity of wheat, barley, grain corn, silage corn, and rice was 0.098 kg MJ−1, 0.086 kg MJ−1, 0.125 kg MJ−1, 0.804 kg MJ−1and 0.052 kg MJ−1, respectively. However, the highest energy productivity was observed in the B–SC (0.481 kg MJ−1) and W–SC (0.462 kg MJ−1) double cropping systems and the lowest was achieved in B–R (0.036 kg MJ−1) (Table 8). The barely–grain corn double-cropped system had the highest specific energy followed by barely–silage corn, barely–rice and winter wheat–silage corn. Net energy was 99,407 MJ ha−1, 84,756 MJ ha−1, 83,997 MJ ha−1and 5103 MJ ha−1in wheat–silage corn, barely–grain corn, barely–silage corn and barely–rice, respectively. The highest net energy was obtained in grain corn by 59,423 MJ ha−1, whereas the lowest (−20,229 MJ ha−1) was related to rice (Table 8). It seems that high level of electricity used was due to electric pumps are old and also high consumption of chemicals and fertilizers could be due to pest invasion and lake of soil analysis which leading to unconscious usage of chemicals. On the other hand, machinery is extensively used for soil preparation, spraying activities and transportation in production process leading to high level of require diesel fuel energy (Rafiee et al.,2010;Singh et al., 2004). 3.4. Energetic of producing cereals and double-cropped systems The total energy input consumed in wheat, barley, grain corn, silage corn and rice could be classified as direct, indirect, renewable and non-renewable energy. The barely–rice double-cropped systems had the highest direct energy (126,254 MJ) followed by wheat–silage corn (84,939 MJ), barely–grain corn (80,578 MJ) and barely–silage corn (78,939 MJ). The highest (55,482 MJ) indirect energy was related to wheat–silage corn and the lowest (46,708 MJ) was obtained in barely–rice double-cropped systems. Amounts of renewable and non-renewable energy in the double-cropped systems are illustrated in Table 10. The highest records for renewable and non-renewable energy were in the barely–rice. The share of indirect and non-renewable energy input was higher than direct and renewable energy in all crops and double-cropped of cereals. Therefore, it is necessary to increase the share of renewable energy for achieving high energy efficiency and energy productivity in agroecosystems. Saving in diesel fuel by changing tillage method can enhance energy use efficiency. Due to the highly mechanized agricultural system in Iran, fuel consumption has risen by 10% in recent years (BeheshtiTabar et al., 2010). Ghorbani et al. (2011) reported that the share of non-renewable energy (76%) compared to renewable energy (24%) was higher in irrigated and dry-land wheat production systems in Iran. Change of agricultural systems towards using low inputs of fossil energy would contribute to reduce CO2and N2O emissions (Shahan et al.,2008;Zahid et al.,2010). Our findings indicated that fertilizers especially nitrogen were one of the main input energy that caused to emission of N2O, so, should be applied by alternative resource such as residual crops, legumes, and manure (McLaughlin et al., 2000). Traditionally, legumes have been viewed as excellent sources of nitrogen in agriculture (Kinzig and Socolow, 1994). Crop rotations with legumes, capable for fixing atmospheric nitrogen, can maintain production levels with reduced reliance on energy intensive mineral fertilizers (Shahan et al., 2008). 4. Conclusions Based on the present study the following conclusions are drawn: 1. The total energy input of 140,422 MJ ha−1(W: 68,104 MJ ha−1+SC: 72,318 MJ ha−1), 128,979 MJ ha−1(B: 59,043 MJ ha−1+GC: 69,937 MJ ha−1BSC), 121,360 MJ ha−1(B: 59,043 MJ M. Zahedi et al. / Energy Reports 1 (2015) 43–49 49 ha−1+SC: 72,318 MJ ha−1) and 172,962 MJ ha−1(B: 59,043 MJ ha−1+R: 113,920 MJ ha−1) were required for different double cropping systems, respectively. 2. The share of diesel fuel by 43.36% (W–SC), 43.93% (B–GC), 42.82% (B–SC) and 49.40% (B–R) was the highest input. This was followed by fertilizer (W–SC: 24.70%, B–GC: 25.12%, B–SC: 27.05 and B–R: 16.11) and water (W–SC: 10.54%, B–GC: 11.76%, B–SC: 10.73 and B–R: 13.85), respectively. 3. The energy use efficiency was found as 1.70 for W–SC, 1.65 for B–GC, 1.64 for B–SC and 1.03 for B–R double cropping systems, respectively. 4. The energy productivity were found as 0.46 for W–SC, 0.11 for B–GC, 0.48 for B–SC and 0.063 for B–R double cropping systems, respectively. Acknowledgment I would like to thank Iran National Science Foundation (INSF), whose funding has made this research possible. References Alam, M.S., Alam, M.R., Islam, K.K., 2005. Energy flow in agriculture: Bangladesh. Am. J. Environ. Sci. 1, 213–220. Asgharipour, M.R., Mondani, F., Riahinia, S., 2012. Energy use efficiency and economic analysis of sugar beet production system in Iran: A case study in Khorasan Razavi province. Energy 44, 1078–1084. Barber, A., 2004. Seven case study farms: Total energy and carbon indicators for New Zealand arable and outdoor vegetable production. In: Arable and Outdoor Vegetable Energy and Carbon Indicators. AgriLINK New Zealand Ltd. BeheshtiTabar, I., Keyhani, A., Rafiee, S., 2010. Energy balance in Iran’s agronomy (1990–2006). Renew. Sustain. Energy Rev. 14, 849–855. Browning, P.W., 2011. Agronomic and economic comparison of full-season and double-cropped small grain and soybean systems in the mid-Atlantic USA (M.S. thesis), In: Crop and Soil Environmental Sciences. Faculty of the Virginia Polytechnic Institute and State University. Canakci, M., Topakci, M., Akini, I., Ozmerzi, A., 2005. Energy use pattern of some field crops and vegetable production: Case study for Antalya region, Turkey. Energy. Con. Manage. 46, 656–666. Demircan, V., Ekinci, K., Keener, H.M., Akbolat, D., Ekinci, C., 2006. Energy and economic analysis of sweet cherry production in Turkey: a case study from Isparta province. Energy Convers. Manage. 47, 1761–1769. Erdal, G., Esengun, K., Erdal, H., Gunduz, O., 2007. Energy use and economical analysis of sugar beet production in Tokat province of Turkey. Energy 32, 35–41. Esengun, K., Erdal, G., Gunduz, O., Erdal, H., 2007. An economic analysis and energy use in stake–tomato production in Tokat province of Turkey. Renew. Energy 32, 1873–1881. Ghasemi-Mobtaker, H., Keyhani, A., Mohammadi, A., Rafiee, S., Akram, A., 2010. Sensitivity analysis of energy inputs for barley production in Hamedan Province of Iran. Agric. Eco. Environ. 137, 367–372. Ghorbani, R., Mondani, F., Amirmoradi, S., Feizi, H., Khorramdel, S., Teimouri, M., Sanjani, S., Anvarkhah, S., Aghel, H., 2011. A case study of energy use and economical analysis of irrigated and dry land wheat production systems. Appl. Energy 88, 283–288. Haj-SeyedHadi, M., Darzi, M., Sharifi-Ashoorabadi, E., 2009. Study the effects of conventional and low input production system on energy efficiency of Silybumm arianum L. World. Academy. Sci. Engin. Technol. 54, 364–366. Khan, S., Khan, M.A., Hanjra, M.A., Mu, J., 2009. Pathways to reduce the environmental footprints of water and energy inputs in food production. Food Policy. 34, 141–149. Khan, M.A., Khan, S., Mushtaq, S., 2007. Energy and economic efficiency of wheat production using different irrigation supply methods. Soil Environ. 26, 121–129. Kinzig, A.P., Socolow, R.H., 1994. Human impacts on the nitrogen cycle. Phys. Today. 47, 24–31. Koocheki, Alireza, Ghorbani, Reza, Mondani, Farzad, Moradi, Rooholla, Alizade, Yaser, 2011. Pulses production systems in term of energy use efficiency and economical analysis in Iran. Inter. J. Energy Eco. and Poli. 1, 95–106. McLaughlin, N.B., Hiba, A., Wall, G.J., King, D.J., 2000. Comparison of energy inputs for inorganic fertilizer and manure based corn production. Can. J. Agric. Eng. 42, 2.1–2.14. Ministry of Agriculture of Iran (MAJ), 2011 Portal of Iranian Agriculture, http://www.maj.ir/english/Main/Default.asp. Newbold, P., 1994. Statistics for Business And Economics. Englewood Cliffs, Prentice-Hall. Rafiee, S., Mousavi-avval, S., Mohammadi, A., 2010. Modeling and sensitivity analysis of energy inputs for apple production in Iran. Energy 35, 3301–3306. Rathke, G.W., Diepenbrock, W., 2006. Energy balance of winter oilseed rape (Brassica napus L.) cropping as related to nitrogen supply and preceding crop. Europ. J. Agron. 24, 35–44. Rathke, G.W., Wienhold, B.J., Wilhelm, W.W., Diepenbrock, W., 2007. Tillage and rotation effect on corn–soybean energy balances in eastern Nebraska. Soil. Till. Res. 97, 60–70. Rezvani Moghaddam, P., Feizi, H., Mondani, F., 2011. Evaluation of tomato production systems in terms of energy use efficiency and economical analysis in Iran. Not. Sci. Biol. 3, 58–65. Safa, M., Mohtasebi, S.S., Behroozi Lar, M., Ghasemi-Varnamkhasti, M., 2010. Energy consumption in production of grains prevalent in Saveh. Iran. African. J. Agric. Res. 5, 2637–2646. Sahabi, H., Feizi, H., Amirmoradi, S., 2012. Which crop production system is more efficient in energy use: wheat or barley? Environ. Dev. Sustain. 12, 9402–9404. Shahan, S., Jafari, A., Mobli, H., Rafiee, S., Karimi, M., 2008. Energy use and economical analysis of wheat production in Iran: A case study from Ardabil province. J. Agric Technol. 4, 77–88. Sheikh-Davoodi, M.J., Houshyar, E., 2009. Energy consumption of canola and sunflower production in Iran. American-Eurasian. J. Agric. Environ. Sci. 6, 381–384. Singh, H., Mishra, D., Nahar, N.M., 2002. Energy use pattern in production agriculture of a typical village in arid zone. India-part I. Energy. Convers. Manage. 43, 2275–2286. Singh, G., Singh, S., Singh, J., 2004. Optimization of energy inputs for wheat crop in Punjab. Energy. Convers. Manag. 45, 453–465. Tsatsarelis, C.A., 1991. Energy requirements for cotton production in central Greece. J. Agric. Eng. Res. 50, 239–246. Yousefi, M., Khoramivafa, M., Mondani, F., 2014. Integrated evaluation of energy use, greenhouse gas emissions and global warming potential for sugar beet (Beta vulgaris) agroecosystems in Iran. Atmos. Environ. 92, 501–505. Zahedi, M., Eshghizadeh, H.R., Mondani, F., 2014. Energy use efficiency and economical analysis in cotton production system in an Arid region: A case study for Isfahan Province. Iran. Inter. J. Energy Eco. and Poli. 4, 43–52. Zahid, H., Azam Khan, M., Irfan, M., 2010. Water energy and economic analysis of wheat production under raised bed and conventional irrigation systems: A case study from a semi-arid area of Pakistan. Soil. Tillage. Res. 109, 61–67.