1Researcher of Center of Advanced Research and Development of Elite Affairs, ETKA, Tehran, IR Iran; firstname.lastname@example.org
2Assisstant Professor of Department of Agricultural Machinery Engineering, Faculty of Agricultural Engineering and Technology, University of Tehran, Karaj, Iran; email@example.com
*Corresponding author: Seyed Hashem Mousavi
Energy use is one of the key indicators for developing more sustainable agricultural practices. Mechanization development strategies require both the quantitative and qualitative assessments of the mechanization indices and their impacts on agricultural production (yield) and economic factors. The main objectives of this study were assessing the mechanization status and introducing strategies for optimization of energy consumption in field operations of crop productions in Varamin agricultural complex, Tehran, Iran, where there is an intensive agricultural crops production in the country. The results from this study indicates that the majority of operational energy used for crop production was derived from mechanical power. Energy management should be considered as an important issue in terms of sustainable, efficient and economic use of energy. Modification of operations, where possible, to make the best use of energy price structures, increasing the use of energy from renewable sources through application of composts, chopped residues or other soil amendments and also employing the conservation tillage methods would be useful not only for providing higher energy use efficiency and decreasing production costs, but also for reducing negative effects to the environment.
Energy has a key role in economic and social development but there is a general lack of rural energy development policies that focus on agriculture. Agriculture has a dual role as user and supplier of energy (FAO, 2000). Energy use is one of the key indicators for developing more sustainable agricultural practices. Wider use of renewable energy sources, increase in energy supply and efficiency of use can make a valuable contribution to meeting sustainable energy development targets (Streimikiene et al., 2007).
In agriculture, a wide range of modern and traditional energy forms are used directly on the farm, e.g. as tractor or machinery fuel, and in water pumping, irrigation and crop drying, and indirectly for fertilizers and pesticides. Other energy inputs are required for post harvest processing in food production, packaging, storage, transport and cooking (FAO, 2000). Energy consumption in agriculture has developed in response to rising population in around the world, limited supply of arable land, and desire for higher standards of living (Kennedy, 2000).
Effective use of energy in agriculture is an important parameter in the evaluation of the environmental impact of production systems (Liu et al., 2010). It is important, therefore, to analyze cropping systems in energy terms and to evaluate alternative solutions.
Agricultural mechanization implies is the application of various power sources and improved farm tools and equipment to agriculture, largely as a means to enhance the productivity of human labor and often to enhance the cropping intensity, precision and timelines of efficiency of utilization of various crop inputs and reduce the losses at different stages of crop production. This includes the use of tractors of various types as well as animal-powered and human-powered implements and tools, and internal combustion engines, electric motors, solar power and other methods of energy conversion. Mechanization also includes irrigation systems, food processing and related technologies and equipment.
Mechanization technology is, therefore, location-specific and dynamic. It require to be appropriate, that is, compatible with local, agronomic, socio-economic, environmental and industrial conditions. The quality of inputs of mechanization, and consequently land and labor productivity in both situations, may differ considerably (Singh and Chandra, 2002). The issue of agricultural mechanization and labor displacement is of great importance in densely populated developing countries with high unemployment (Farman and Parikh, 1992).
Several authors had investigated the mechanization indicators with reference to the intensity of power availability, and its impact on agricultural production and productivity of inputs were analyzed. Giles (1975) investigated power availability in different countries, and demonstrated that productivity was positively correlated with potential unit farm power. Binswanger (1982) defined the status of mechanization by the growth of mechanically power-operated farm equipment over traditional human and animal power operated equipment. Singh (2006) for investigating the impact of mechanization on crop production and economic indicators in India, suggested a mechanization index based on the ratio of the cost of use of machinery to the total animate and machinery cost. Also, in this study the major factors that required higher capital investment such as fertilizer, irrigation and farm power inputs were selected and their impacts on yield through multiple linear regressions were assessed.
Many researchers have studied energy and economic analysis to determine the energy efficiency of plant production such as sugarcane in Morocco (Mrini et al., 2001), rice in Malaysia (Bockari-Gevao et al., 2005), pear production in China (Liu et al., 2010), onion production in Pennsylvania (Moore, 2010), sunflower production in Greece (Kallivroussis et al., 2002), winter oilseed rape in Germany (Rathke and Diepenbrock, 2006) and barley production in Iran (Mobtaker et al., 2010). Moreover, comparing the high and low levels of farming technologies in energy and economically points of view, Zangeneh et al. (2010) reported that potato production in high level of technology had the higher energy use efficiency and economical productivity.
Also, Nandal and Rai (1987) conducted a study by dividing Haryana in three homogenous zones on the basis of intensity of mechanization. In all, 54 farms were selected from each of the three zones making a total sample of 162 farming households. The impact of mechanization on crop yield was studied on three different categories of farms. It was apparent from the study that the tractor-operated farms had higher yield of wheat and paddy. In case of farms using tractors on custom - hire basis, the yield was comparatively low. The study revealed that tractor-owing farms invariably used higher level of agricultural inputs and had better control on timeliness of operations.
Based on the literature there was no study on strategies for optimization of energy consumption in field operations of crop productions. Therefore, the main objectives of this study are assessing the mechanization status and introducing strategies for optimization of energy consumption in field operations of crop productions in Varamin agricultural complex, Tehran, Iran, where there is an intensive agricultural crops production in the country.
Materials and methods
Data collection and processing
The study was carried out in Varamin agricultural complex, Tehran, Iran, which is an important producer of wheat, barley, alfalfa, canola, forage maize, medicinal plants, pea, etc. in the country. Data were collected by using a face to face questionnaire method from farm managers in the region. The primary data set was consisted of 100 explanatory parameters for each farm covering all characteristics on farming inputs and outputs in the region.
Analysis of mechanization indices
The mechanization status may be assessed based on the general concept of mechanization. The Mechanization Capacity (MC) index may be investigated by the ratio of total mechanical energy used per hectare of crop production, using the following equation:
where MC is the mechanization capacity (kWh ha-1) for every farm, Pi denotes the rated power of tractors or combine harvesters (kW) in ith operation i, η is the correction factor for utilized power (0.75) and Cai presents the field capacity for the operation i (ha h-1). So the average mechanization capacity for crop production in the region may be estimated by the average mechanization capacity of farms under consideration.
In order to specify the mechanization status, a mechanization indicator based on the ratio of mechanical energy used by tractors and combine harvesters per hectare of crop production over total farm operational energy including human labor and mechanical energy inputs can be introduced as a measure of qualitative assessment of modernization of agriculture.
where MI is the mechanization index in decimal, ME represents the total mechanical energy used per unit area of soybean production (kWh ha-1) and HLE denotes the human labor energy (kWh ha-1). Energy consumed by human labor input was calculated by multiplying the total employed time of labor per unit area (h ha-1) by its energy conversion factor. The energy conversion factor was found to be 1.96 MJ h-1; so the human labor energy was calculated in MJ ha-1, and it is transformed into kWh ha-1, using 1 kWh=3.6 MJ equation.
Moreover, the contribution of operational costs from total cost of production can be calculated.
Results and discussions
Table 1 presents the agricultural crops produced in the case study region and land area of crops. The results revealed that the wheat is the main crop produced in this agricultural complex by 160 ha land area and 24.4% from total land area of the farm. The other main crops are barley, alfalfa and forage maize by 140 ha, 140 ha and 133 ha land area, respectively. Land area of canola was 52 ha. Also, medicinal plants and pea were produced at 20 ha and 10 ha land area, respectively. Total land area of this agricultural complex was calculated as 655 ha. From these results it is concluded that, cereals are the main crops produced in the farms; so, for optimization of energy consumption, and also, production costs, focuses on the field operations of these crops is essential.
Table 1. Area of cultivation of different crops in Varamin agricultural complex, Tehran, Iran
Area of cultivation (ha)
Important field operations for these crops are tillage, sowing, irrigation, application, harvesting, transportation and processing for medicinal plants. Therefore, application, harvesting, transportation and tillage are the main energy consuming operations for production of these crops.
Table 2. Mechanization capacity in different operation for soybean production
Mechanization capacity (kWh ha-1)
In another study by Mousavi-Avval et al. (2010), these operations were the main energy consuming operations for soybean production in Golestan province of Iran. They reported that, mechanization capacity was found to be 831.77 kWh ha-1 for the useful mechanical power of tractors and combine harvesters, used in the employment time for one hectare of crop production in the region. The operations of tillage, sowing and irrigation used mechanical energy as 168.19, 52.64 and 22.37 kWh ha-1, respectively. Also they investigated the percentage of mechanical energy used in different operations and It was reported that the major energy consumer in the operations was fertilizer and chemical application, contributed to the total mechanical energy by 27.69%. Also it followed by transportation (22.74%), harvesting (20.33%) and tillage (20.22%), respectively. The shares of sowing and irrigation operations from mechanization capacity were 6.33% and 2.69%, respectively. The summarized results are tabulated in Table 2 (Mousavi-Avval et al., 2010).
For assessing the impact of farm mechanization, we refer to a previous study on soybean production in Iran (Mousavi-Avval et al., 2010). The quantity of human labor energy and contribution of mechanical energy to total operational energy, including human labor and machinery energy inputs are tabulated in Table 3. The results revealed that human labor energy was used as 105.86 (kWh ha-1); it mainly employed for irrigation (29.51 kWh ha-1) and weeding (26.89 kWh ha-1) operations. The share of mechanical energy from total farm operational energy input was found to be 88.71%; indicating that the majority of operational energy used for soybean production was derived from mechanical power. On the other hand, the contribution of mechanical energy consumption from total operational energy in sowing, transportation and tillage operations were found to be 98.73%, 96.95% and 95.32%, respectively; indicating that these operations were accomplished mainly by mechanical power. However, mechanical energy usage for irrigation and weeding operations was relatively low; this indicates that these operations must be mechanized. By assessing the farms and field operations from this study and the previous study, it is evident that, the farm operational energy of these farms is similar to those of previous study. So that, for these farms there is no mechanical equipment for weeding and in sowing operations more labor power is required. So, we can introduce strategies for optimization of energy use in field operations of crop production in Varamin agricultural complex by referring to the quantitative results of previous study by the same authors.
Table 3. Human labor energy and contribution of mechanical energy to total operational energy in soybean production
Share of mechanical energy to total operational energy (%)
Asakereh et al. (2010) investigated the effect of mechanization level on energy use efficiency of apple production. They reported that farms with higher level of mechanization consumed higher machinery and diesel fuel energies. Also, net energy gain of apple production under low level of farming technology was lower than that in high level of farming technology.
To sum it up, applying a better management technique, employing the conservation tillage methods are suggested to reduce the fossil fuel usage and to reduce the environmental impacts.
Application of inputs by performance monitoring and utilization of alternative sources of energy may be also the pathways to make energy usage more environmental friendly, and thus to reduce their environmental footprints.
Improving timing, amount and reliability of water application and improving energy conversion efficiency of water pumping systems may help to reduce water usage and electrical energy. Integrating the legume crops in rotation with soybean, application of composts, chopped residues or other soil amendments may increases soil organic matter content and fertility and so reduces the need for chemical fertilizer energy input.
Moreover, employing the technological upgrade to substitute fossil fuels with renewable energy sources are suggested for optimization of energy use in field operations of agricultural productions in the region.
The high contribution of electrical energy was mainly due to high water application in irrigation operation. The improper use of groundwater in agricultural practices may result in land quality degradation such as soil erosion, salinization and reduction of organic matter. The high water input in farms may exacerbate the problem of soil drainage and excessive leaching of water to shallow groundwater aquifers which may impact groundwater table and soil salinity dynamics (Khan et al., 2009).
Energy management should be considered as an important issue in terms of sustainable, efficient and economic use of energy. Modification of operations, where possible, to make the best use of energy price structures, increasing the use of energy from renewable sources through application of composts, chopped residues or other soil amendments and also employing the conservation tillage methods would be useful not only for providing higher energy use efficiency and decreasing production costs, but also for reducing negative effects to the environment. The extension activities for the farmers in the region are needed to improve the efficiency of energy consumption in crop production in the region.
Energy has a key role in economic and social development but there is a general lack of rural energy development policies that focus on agriculture. Agriculture has a dual role as user and supplier of energy. The main objectives of this study were assessing the mechanization indices and introducing strategies for optimization of energy consumption in field operations of crop productions in Varamin agricultural complex, Tehran, Iran. Also the share of mechanical energy from total farm operational energy including human labor and machinery energy inputs was discussed. The results from this study indicates that the majority of operational energy used for crop production was derived from mechanical power. Fertilizer and chemical application, harvesting, transportation and tillage are the main energy consuming operations for production of these crops, indicating that these operations were accomplished mainly by mechanical power. However, mechanical energy usage for irrigation and weeding operations was relatively low.
Totally, it is concluded that, applying a better management technique, employing the conservation tillage methods, increasing the use of energy from renewable sources through application of composts, chopped residues or other soil amendments are important for reducing the fossil fuel usage and environmental impacts of crop production in the region. Moreover, the extension activities for the farmers in the region are needed to improve the efficiency of energy consumption in crop production in the region.
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