Strategies for optimization of energy use in field operations of agricultural productions

Seyed Hashem Mousavi1*, Majid Khanali2

1Researcher of Center of Advanced Research and Development of Elite Affairs, ETKA, Tehran, IR Iran; moosavi_13848@yahoo.com

2Assisstant Professor of Department of Agricultural Machinery Engineering, Faculty of Agricultural Engineering and Technology, University of Tehran, Karaj, Iran; khanali@ut.ac.ir

*Corresponding author: Seyed Hashem Mousavi

Abstract

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.

Keywords: Agricultural machinery, Energy, Mechanization, Productivity, Varamin agriculture

complex

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Introduction

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

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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

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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

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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:

(1) MC =

∑i=1

n

Pi×η

Cai

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.

(2)MI = ME

ME+HLE

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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,

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Iran

Item Area of cultivation (ha) Percentage (%)

wheat 160 24.4

barley 140 21.4

alfalfa 140 21.4

canola 52 7.9

forage maize 133 20.3

medicinal plants 20 3.1

pea 10 1.5

Total 655 100.0

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

ItemMechanization capacity

(kWh ha-1)Percentage (%)

Tillage 168.19 20.22

Sowing 52.64 6.33

Irrigation 22.37 2.69

Application 230.32 27.69

Harvesting 169.10 20.33

Transportation 189.15 22.74

Total 831.77 100.00

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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

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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

Operation Labor energy

(kWh ha-1)

Share of mechanical energy to total operational

energy (%)

Tillage 8.26 95.32

Sowing 0.68 98.73

Irrigation 29.51 43.12

Application 17.36 92.99

Harvesting 17.21 90.76

Transportation 5.96 96.95

Weeding 26.89 0.00

Total 105.86 88.71

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.

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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

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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.

Conclusions

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.

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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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