Energy Ratio in Dryland Wheat -Case Study: Eghlid Township

Abstract

Energy method is widely used for analyzing problems associated with sustainable agriculture. In this study, energy ratio (ER) of dryland wheat for three regions of Eghlid township was quantified. The total cropping area of Eghlid is nearly 8282 hectares including Khosrowshirin (5000 ha), Sedeh (1682 ha) and Dezhkord (1600 ha); corresponding values of wheat yield are 1, 1.02 and 0.9 ton/ha, respectively. In this township, dryland planting is performed via two methods: mechanized (using moldboard plow and then deep seed drilling) and semi-mechanized (seed broadcasting manually or using seed broadcaster and then moldboard plow). In this study, equivalent energy inputs and outputs for both methods were calculated and then corresponding energy ratio was determined. Inputs were: fertilizer, seed, pesticide, fuel, equipment, human labor, while outputs were considered as grain yield and straw. Grain energy ratio for Khosrowshirin, Sedeh and Dezhkord were obtained as 1.068, 1.19 and 0.91, respectively, while corresponding values related to both grain and straw (total biological output) were 1.61, 1.80 and 1.36, respectively. Consequently, for the township, the corresponding mean values related to grain and both grain and straw were calculated as 1.06 and 1.60, respectively. Input energy of dryland wheat was found to be 12488.2 MJ/ha and total output energy (grain and straw) was 20055.8 MJ/ha leading to the net energy gain (NEG) of 7538 MJ/ha. Mean values of fertilizer, seed, pesticide, fuel consumption, equipment and human labor were 57.5%, 21.1%, 28.4%, 1.25%, 0.38%, and 0.02%, respectively. It is clear that the contribution of fertilizer and fuel inputs have set aside highest values of energy consumption and their magnitudes should be optimized to implement an efficient management. Consuming these inputs not only increases the production costs involved but also the pollution of the atmosphere, soil and water resources is expected as well.

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10th International Congress on Mechanization and Energy in Agriculture
“14-17 October 2008, Antalya-TURKIYE”
409
Energy Ratio in Dryland Wheat - Case Study: Eghlid Township
K. MOLLAEE, A. KEYHANI, M. KARIMI, K. KHAIRALIPOUR,
M. Ghasemi VARNAMKHASTI
Agricultural Machinery Dept., Faculty of Biosystems Engineering, University of Tehran,Iran
E-mail: akeyhani@ut.ac.ir
AbstractEnergy method is widely used for analyzing problems associated with sustainable agriculture. In this
study, energy ratio (ER) of dryland wheat for three regions of Eghlid township was quantified. The total cropping
area of Eghlid is nearly 8282 hectares including Khosrowshirin (5000 ha), Sedeh (1682 ha) and Dezhkord (1600
ha); corresponding values of wheat yield are 1, 1.02 and 0.9 ton/ha, respectively. In this township, dryland
planting is performed via two methods: mechanized (using moldboard plow and then deep seed drilling) and
semi-mechanized (seed broadcasting manually or using seed broadcaster and then moldboard plow). In this
study, equivalent energy inputs and outputs for both methods were calculated and then corresponding energy
ratio was determined. Inputs were: fertilizer, seed, pesticide, fuel, equipment, human labor, while outputs were
considered as grain yield and straw. Grain energy ratio for Khosrowshirin, Sedeh and Dezhkord were obtained as
1.068, 1.19 and 0.91, respectively, while corresponding values related to both grain and straw (total biological
output) were 1.61, 1.80 and 1.36, respectively. Consequently, for the township, the corresponding mean values
related to grain and both grain and straw were calculated as 1.06 and 1.60, respectively. Input energy of dryland
wheat was found to be 12488.2 MJ/ha and total output energy (grain and straw) was 20055.8 MJ/ha leading to
the net energy gain (NEG) of 7538 MJ/ha. Mean values of fertilizer, seed, pesticide, fuel consumption, equipment
and human labor were 57.5%, 21.1%, 28.4%, 1.25%, 0.38%, and 0.02%, respectively. It is clear that the
contribution of fertilizer and fuel inputs have set aside highest values of energy consumption and their
magnitudes should be optimized to implement an efficient management. Consuming these inputs not only
increases the production costs involved but also the pollution of the atmosphere, soil and water resources is
expected as well.
Keywords: Energy ratio; Fuel consumption; Fertilizer; Net energy gain
INTRODUCTION
Food production, especially wheat is strongly
correlated to political and economical powership of
a country (Valdiani et al., 2002). Fast progress in
the population as well as lack of optimized
production approaches jeopardizes the
independence of the developing countries.
In Iran, approximately 2/3 of all drylands have
been devoted to wheat and barley (Mazaheri &
Majnoon Hoseini, 2003). In 2001-2002, the total
area covered by wheat product was estimated
around 6.4 million hectares including 37% irrigated
and 63% dryland farming. Wheat production is
amounted to 13.44 million tons where irrigated and
dryland cropping proportions are 64.77 and
35.23%, respectively. Irrigated and dryland wheat
yields are reported 3.63 and 1.18 ton/ha,
respectively (Anon, 2005).
Conservation of natural resources is the most
important key for a sustainable agriculture. Hence,
given the interaction of agricultural activities with
environment quality, appropriate natural resources
management is a crucial aspect for farms (Sartori et
al., 2005).
Farm lands are the ecosystems where energy is
entered auxiliary (Hassanzadeh Gorttappeh &
Mazahery, 1996). Energy cycle is one of the most
concerned subjects in agricultural ecology. In this
regard, usually energy ratio of the output to the
input is calculated for crops (Dick et al., 1985;
Gillarad, 1993; Kocheki, 1994).
To determine energy balance in the ecosystems,
output and input energy must be compared and
analyzed (Nasirian et al., 2006). Birman et al.
(2003) classified the energy proportionalities into
two methods: economical-environmental method
and economical method. In a sustainable
agriculture, a specified level of production is
expected to be maintained. Process of using the
production sources should be in such a manner that
in addition to satisfying the food needs of the
present generation, food resources of the future
generation should not be jeopardized as well.
Taking into account such attitude, no one should
merely consider the income.
In order to prevent any malfunction in subsidies,
its management especially in agriculture, should be
considered and systems should be designed in such

10th International Congress on Mechanization and Energy in Agriculture
“14-17 October 2008, Antalya-TURKIYE”
410
a way that, besides the economical performance,
energy consumption is balanced for sustainable
agriculture. One basic solution, for instance, is
direct distribution of subsidies to farmers.
Safa and Tabatabaeefar (2002) investigated the
energy consumption to produce dryland and
irrigated wheat at Saveh region. The resulted
energy ratio ranged from 0.68 to 1.17 for irrigated
and 0.99 for dryland wheat. They reported
20.9GJ/ha for irrigation activity as the maximum
input energy for the irrigated crop and 5.7GJ/ha for
fertilizer application as the maximum input energy
for dryland wheat.
Nasirian et al. (2006), in Khazaee Farming
Industry, by assessment and comparison of energy
consumed for sugarcane production in three
cropping systems, concluded that the most input
energy is electricity required for irrigation. They
determined energy ratio around 5. Also, input
energy consisted 75% of direct energy and 25% of
indirect energy. Based on their report, electricity
proportion was maximum for diesel fuel
consumption for irrigation and then for N fertilizer.
Valdiani et al. (2002), calculated energy ratio of
dryland wheat in fields of seed growing located in
East Azerbaijan province. They reported that the
corresponding value for biological yield (grain and
straw) was 0.778, while for grain and straw were
0.424 and 0.364, respectively. They reported that
the most consumed energy was related to N
fertilizer as 29.88% and the least was related to
human labor as 0.39%.
This study was conducted to investigate the
dryland wheat production system related to energy
consumption to find energy losses, to present a
method for decreasing input energy and increasing
output energy, and if necessary, to alternate the
procedure of land use.
MATERIAL AND METHODS
Region condition
Eghlid is located in the north of Fars province
with total area of 7205 km2 located in 52° and 42'
longitude east and 30° and 50' latitude north. The
altitude ranges from 2000 to 2500 m above sea
level, with annual rainfall of 250 to 400mm. The
maximum and minimum temperatures are 38 °C
and -22 °C, respectively. Eghlid is ranked as the
second wheat producer region in Fars. Its annual
production is amounted to 170×103 tons where 7%
is accounted for dryland wheat (Anon., 2005).
Direct energy inputs for energy analysis in wheat
production include operational energy consumption
and energy embedded in field machineries. Indirect
energy inputs account for fertilizers, pesticides, seed,
human labor, etc. Energy consumption in wheat
production operations including tillage machineries,
planters, fertilizer broadcasters, sprayers, and
combine harvesters were determined in dryland
system. Equivalent energy inputs were obtained for
fuel, machineries, seed, fertilizer, and pesticide using
the energy intensities given in reference Ovtit-
Canavate & Hernanz (1999) and for straw in reference
Singh & Mittal (1992). For dryland wheat, application
of potash fertilizer (K2O) was prevalent only in
Khosrowshirin among the studied regions. For
pesticide spraying, energy consumption included the
fuel energy to move the tractor and the sprayer, plus
the pesticide used. Human labor is being involved in
almost all tasks on the farm, from driving machineries,
maintenance, repair, spraying, and fertilizer to
management. However, according to human labor
situation in Iran (Keyhani, 2006), the energy
consumption for a worker was considered as 2.146
MJ/day (for 8 working hours per day equivalent to 0.1
hp) and the total labor energy was determined by
multiplying the number of workers by the above
mentioned coefficient. One must recognize that
although the labor energy is low compared to other
inputs, it is the most expensive form of energy in field
operations in Iran. Fuel equivalent energy calculated
by obtaining the consumed fuel for different
operations, was determined by questioners, knowing
the degree of mechanization found from Anon. (2005)
and then using the following equation:
∑∑
==
=
n
i
iji
k
j
j
tDFCFC
11
(1)
Where:
FCtj = total fuel consumption for all operations in
the region jth, L/ha
FCi = fuel consumption for the ith operation per
ha, L/ha
Dij = degree of mechanization for the ith operation
in the jth region, decimal
Equivalent energy embedded (sequestered) in all
machineries (MJ/ha) was calculated by multiplying the
energy intensity (MJ/kg) (Ovtit-Canavate & Hrnaz,
1999) by the amount of machinery weight used per
hectare (kg/ha) considering the operation time per
year and the life span of the machine. The required
information for each operation was obtained by
questioners and Anon. (2005). Energy level for
three specified regions were determined.
As it was mentioned previously, in energy
proportionality, two general methods are considered:
economical-environmental and economical. In this
research, the latter method was used. The output
energy corresponds to both grain seeds and straw.
The major amount of straw is directly consumed by
animals and the rest is returned to the soil. To

10th International Congress on Mechanization and Energy in Agriculture
“14-17 October 2008, Antalya-TURKIYE”
411
calculate the output energy, the amount of produced
grain and straw were attained by questioners and
then multiplied to the appropriate energy intensities
for grain (Ovtit-Canavate & Hrnaz, 1999) and that for
straw (Singh & Mittal, 1992). The result is shown in
Table 1.
Energy ratios of biologic yield (grain and
straw) and that of grain only were determined using
the followings:
EnergyInputTotal
E
nerg
y
OutputgicBioloTotal
RatioEnergyYieldgicBiolo =
EnergyInputTotal
EnergyOutputGrainTotal
RatioEnergyYieldGrain =
Finally, the net energy gain (N.E.G) was determined
by the following relation: N.E.G = (output energy/ha)-
(input energy/ha)
Table. 1. The amount of grain and straw
production and corresponding energies.
Table. 2. The measured parameters based on energy ratio of grain and biologic materials (grain and straw).
Grain and straw grain
N.E.G
(MJ/ha)
E.R
Output
Energy
(MJ/ha)
N.E.G
(MJ/ha)
E.R
Output
Energy
(MJ/ha)
Input
Energy (MJ/ha)
Region
10584.5 1.80 23587.5 2597 1.19 15600 13003.4 Sedeh
7427 1.61 19637.5 789.5 1.07 13000 12210.5 Khosrowshirin
4684.5 1.36 17527.5 -1143.4 0.91 11700 12843.04 Dezhkord
7538 1.60 20055.8 783.2 1.06 13238.3 12488.2 Average
RESEARCH RESULTS
As can be seen in Table 2, the net energy gain
(NEG) for grain only for Dezhkord was -1143.4
MJ/ha, and corresponding value considering both
grain and straw was 4684.5, but farmers in this region
continue that due to economical performance.
Unfortunately, no base reference is available in
the country for fuel consumption. The amount of
chemical fertilizer consumption in Eghlid township, in
the Fars province and also in Iran are shown in Table
3 (Anon., 2003). As can be seen, fertilizer
consumption in Eghlid is higher than that of Fars
province and Iran.
Grain
and straw
straw grain
output
Energy
(MJ/ha)
Output
Energy
(MJ/ha)
Energy
Intensity
(MJ/kg)
Straw
(dry mass
kg/ha)
Output
Energy
(MJ/ha)
Energy
Intensity
(MJ/kg)
Crop
production
(kg/ha)
Region
23587.5 7987.5 12.5 639 15600 13 1200 Sedeh
19637.5 6637.5 12.5 531 13000 13 1000 Khosrowshirin
17527.5 5827.5 12.5 466.2 11700 13 900 Dezhkord
20055.8 6817.5 12.5 545.4
13238.
3
13 1033.33 Average

10th International Congress on Mechanization and Energy in Agriculture
“14-17 October 2008, Antalya-TURKIYE”
412
The fertilizer energy consisted 57.5% of the total
consumed energies which was maximum compared to
that of other inputs (Fig 1). This result is higher than
that of Saveh, 41.7% (Safa and Tabatabeefar, 2002),
and East Azerbaijan, 32.28% (Valdiani et al, 2002).
Nitrogen fertilizer application and also the fuel
consumption in East Azerbaijan province were 8.591
GJ/ha (110 kg/ha) and 6.66 GJ/ha (129 L/ha),
respectively. These figures are higher than those
obtained for Eghlid township (6.404 GJ/ha (82 kg/ha)
and 3.537 GJ/ha (74 L/ha), respectively). This fact
should be taken into consideration that input energy
in East Azerbaijan have led to 11.05 GJ/ha output
energy corresponding to 850 kg/ha yield which is
significantly lower than that of Eghlid with 13.273
GJ/ha (1021 kg/ha yield). This has reflected itself to
the energy ratio of Eghlid as well, which is higher than
that of East Azerbaijan.
Table. 3. The fertilizer consumption in Eghlid region, Fars province and Iran.
57.5
28.4
12.1
1.25 0.38 0.02
0
10
20
30
40
50
60
70
Fertilizer Diesel Seed Machinery Pesticide Labor
Input factors
percentage of input energy
Fig 1. Percentage of each input to produced dryland wheat.
Total (kg/ha) P2O5 (kg/ha) N (kg/ha)
116 33.87 82.22 Eghlid
79.52 34.16 45.36 Fars province
80 38.55 41.47 Iran

10th International Congress on Mechanization and Energy in Agriculture
“14-17 October 2008, Antalya-TURKIYE”
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production in Khosrowshirin, Sedeh, and Dezhkord
Table. 4. The input energy consumption for
grain production.
was determined as 12.2, 10.92, and 14.27 MJ,
respectively, (Table 4).
Energy ratio obtained in Sedeh was
maximum (1.80) compared to that of other regions.
This is may be due to higher degree of
mechanization for deep planting operation
compared to that of Dezhkord and higher rainfall
compared to that of Khosrowshirin (Table 5).
Table. 5. The degree of mechanization for deep
planting operation and rainfall in studied regions
(Anon., 2005).
Rainfall
(mm/year)
Degree of
Mechanization
(%)
Region
6125Dezhkord
40680 Khosrowshirin
57360 Sedeh
The amount of energy ratio is not available for
Iran, hence, no comparison can be conducted in that
scale. For the region, it can be concluded that the
higher the energy ratio, the higher the yield. Energy
ratio obtained in Eghlid township (related to grain
only) was calculated as 1.062 slightly higher than that
in Saveh region reported by Safa and Tabatabeefar
(2002) as 0.99. The energy ratio was considerably
higher than that of East Azerbaijan which was
reported as 0.424 by Valdiani et al. (2002).
CONCLUSION
The two highest consumed input energies were
that of fertilizer and fuel (Fig 1); therefore, their
consumption should be correctly optimized. In this
regard, field application of the fertilizer should be
managed by soil sampling and determination of lack
of elements. Effectiveness of fertilizer application in
dryland fields drastically depends on both date and
rainfall amounts; therefore, applying the N fertilizer as
dressing in two discrete stages should be carried out
considering both date and rainfall amount. In order to
reduce the fuel consumption as well as preserving the
soil structure and its moisture, using the chisel plow
and deep seed drill should be practiced. Performing
the latter operation may increase the product yield
and energy ratio. Applying effective management and
using financial support can help to achieve the
considered goals.
ACKNOWLEDGMENTS
The authors would like to thank office of
Jihad-e-Agriculture and farmers of Eghlid
township for their valuable help in providing the
required information.
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