Analysis of energy flow and indicators
In the first step of this section, the input and output energy pattern and also energy indicators were calculated. Table 2 shows the amount of inputs and output and the share of each them in cantaloupe production (all the calculations for 1 ha). The results of calculating energy indices showed that the total inputs and output energies are 27155.86 and 15380 MJha− 1.
Table 2
The input-output energy of cantaloupe production
Item
|
Unit
|
Quantity per unit area (ha)
|
Total energy equivalent (MJ)
|
A. Inputs
|
|
|
|
Human labor
|
h
|
832.98
|
1632.63
|
Agricultural machinery
|
h
|
27.61
|
1731.45
|
Diesel fuel
|
L
|
147.18
|
8287.42
|
Lubricant oil
|
L
|
2.42
|
115.54
|
Nitrogen (N)
|
kg
|
132.54
|
8766.03
|
Phosphate (P2O5)
|
kg
|
39.96
|
497.13
|
Chemical toxins
|
L
|
4.25
|
656.10
|
Seed
|
kg
|
106.25
|
106.25
|
Electricity
|
kwh
|
106.50
|
1270.55
|
Water for irrigation
|
M3
|
4012.50
|
4092.75
|
Total energy input
|
MJha− 1
|
-
|
21792.56
|
B. Output
|
|
Yield
|
kg
|
19225
|
15380
|
The results of Table 2 indicated that nitrogen fertilizer and diesel fuel with 8766.03 (32.28%) and 8287.42 (30.52%) MJha− 1 had the highest share of input energy consumption followed by irrigation (15.07%), agricultural machinery (6.38%), human power (6.01%) and electricity (4.68%) energies. Figure 5 shows the share of each input in cantaloupe production.
Machine operations such as primary and secondary plowing, canalization, spraying and transportation can increase the fuel consumption in cantaloupe production. The prevailing belief of farmers about the role of chemical fertilizer such as N in increasing the crop production also led to the use of nitrogen fertilizer regardless of soil testing. The human energy consumption in sowing, irrigation and harvesting operations can increase the total energy consumption of cantaloupe production. The highest consumption of human power input was related to the presence of labor in the field to take care of the crop such as weeding control, harvesting and seeding operations. In a similar study, the number of man-hours and agricultural machinery used to produce 1 ha of cantaloupe production was reported about 606.3 and 177.1 hours, respectively. Also, the highest amount of energy consumed was related to electricity (45.4%), nitrogen fertilizer (21.4%), irrigation (18.4%), agricultural machinery (8.1%), diesel fuel (6.6%) and micro fertilizers (4.3%). The results of that study indicated that the low fuel consumption was related to the lack of tractor for spraying the chemical poisons for weed control which was done by labors (AsghariPour and Jami Alahmadi 2016).
Sharifi et al. (2018) In research evaluated the relationship between energy inputs, yield and cost in melon production. Energy use efficiency and energy productivity were 0.18 and 0.23 Kgmj− 1, respectively. Also, Specific energy and net energy was estimated 4.4 MJKg− 1 and − 875055 MJha− 1 respectively. The total input energy in this study estimated 1069332.26 MJha− 1. They reported that diesel fuel with 874578.76 MJ ha− 1 (0.81.79%) and farmyard manure with 142603.29 MJha− 1 (0.13.34%) had the largest share of inputs in the production of melons respectively. moreover, the human labor with 2119.54 MJha− 1 (0.20%) and the seed with 3 MJha− 1 (0.00%) had the lowest input energy in the production of melons (Sharifi 2018).
Figure 6 classified that total energy consumption in cantaloupe production into direct, indirect, renewable and non-renewable. Figure 6 indicated that, the share of indirect, renewable and non-renewable energies in cantaloupe production were 57%, 43%, 94% and 06%, respectively. In a similar research, the share of direct, indirect, renewable and non-renewable energy in cantaloupe production was reported to be 71.2%, 28.8, 19.5% and 80.5%, respectively (AsghariPour and Jami Alahmadi 2016). Table 3 reports the results of energy indices in cantaloupe production. In other study the total of renewable and non-renewable energy in melon production, were 15.05% and 84.95%, respectively. Also the share of direct and indirect energy were 83.03% and 16.97%, respectively (Sharifi 2018).
Table.3. Energy indices for cantaloupe production in Darehshahr Region
Item
|
Unit
|
Value
|
Energy use efficiency
|
-
|
0.56
|
Energy productivity
|
KgmJ− 1
|
0.70
|
Specific Energy
|
MJkg− 1
|
1.41
|
Net energy gain
|
MJha− 1
|
-11775.86
|
Direct energy
|
MJha− 1
|
15398.89
|
Indirect energy
|
MJha− 1
|
11756.96
|
Renewable energy
|
MJha− 1
|
1738.88
|
Nonrenewable energy
|
MJha− 1
|
25416.98
|
According to the results of Table 3, energy use efficiency, energy productivity, specific energy and net energy gain were calculated as 0.56, 0.70 Kgmj− 1, 1.41 MJkg− 1 and − 11755.86 MJha− 1, respectively. Low price of diesel fuel and the lack of incentive and punitive policies for producers with optimal consumption are the reasons for high consumption of diesel fuel in the process of production of cantaloupe and other agricultural products in Iran. In general, in the production of cantaloupe, factors such as the use of deep plowing for primary tillage, the use of worn-out tractors and the old mechanism in agricultural machinery led to the excessive use of diesel fuel. The small size of farms and the transportation of inputs by agricultural machinery on a small scale were other reasons for the reduced efficiency of the use of inputs in the study area. Furthermore Comparison of energy indicators of cantaloupe production system in comparison with other products shows the inefficiency of energy consumption in the production of this product, which further reveals the need for optimization. AsghariPour and Jami Alahmadi 2016 reported that the energy use efficiency, energy productivity, specific energy and net energy gain in cantaloupe production in Torbat-e-Jam region were 0.22, 0.116 Kgmj− 1, 8.59 MJkg− 1 and − 105425.2 MJ, respectively. The authors reported that high electricity consumption for water extraction from deep wells, improper use of agricultural machinery and excessive use of chemical pesticides (11.3 litha− 1) is the reason of high energy consumption for cantaloupe production in Torbat-e-Jam (AsghariPour and Jami Alahmadi 2016). In the study of energy indices of paddy production in northern Iran, diesel fuel (44.34%) and nitrogen fertilizer (14.94%) had the highest and fungicide (0.52%) and herbicide (1.67%) the lowest input energy Dedicated to themselves (Nabavi-Pelesaraei et al. 2018).
Evaluation and analysis of environmental indicators in cantaloupe production
Chemicals (fertilizers or poisons) can be released into the environment (air, water and soil.) at the all stages of the life cycle of products, services, and systems. Emissions from various products may contain hundreds of chemicals that many of them have the potential to adversely affect the ecosystems. So, to assess the environmental impact of a crop production system, all aspects of system must be considered (Khoshnevisan et al. 2014). In this section, first, the amount of impact categories studied in cantaloupe production is presented and in the next step, the effects of inputs consumption on four endpoint impact categories were evaluated. Table 4 shows the number of environmental indicators that calculated in ton of cantaloupe production. The amount of global warming potential was estimated at 155.66 kg equivalent to carbon dioxide (2957 kg CO2 eq per hectare). In a similar study in Nepal, the amount of greenhouse gas emissions per hectare for garlic, rice, corn, wheat and lentils was 2997.13, 1798.27, 1888.19, 839.19 and 149.85 kg CO2 eq per hectare (Pokhrel and Soni 2019). Potential amount of carcinogenic and non-carcinogenic substances, ionizing radiation, Aquatic acidification and Aquatic utrification were calculated about 2.65 kgc2H3cI eq, 17.95 kgc2H3cI eq, 597.85 Bq C-14 eq, 0.81 Kg SO2 eq and 0.01 kg PO4 -lim respectively.
Table.4. Amount of input emissions for each impact category based on one ton of cantaloupe production
|
Indicator
|
Unit
|
Value
|
Carcinogens
|
kg C2H3Cl eq
|
2.65
|
Non-carcinogens
|
kg C2H3Cl eq
|
17.95
|
Respiratory inorganics
|
kg PM2.5 eq
|
41.76
|
Ionizing radiation
|
Bq C-14 eq
|
597.85
|
Ozone layer depletion
|
kg CFC-11 eq
|
0.00
|
Respiratory organics
|
kg C2H4 eq
|
0.06
|
Aquatic ecotoxicity
|
kg TEG water
|
21230.62
|
Terrestrial ecotoxicity
|
kg TEG soil
|
51373.52
|
Terrestrial acid/nutrients
|
kg SO2 eq
|
4.97
|
Land occupation
|
m2org.arable
|
1323.60
|
Aquatic acidification
|
kg SO2 eq
|
0.81
|
Aquatic eutrophication
|
kg PO4 P-lim
|
0.01
|
Global warming
|
kg CO2 eq
|
155.66
|
Non-renewable energy
|
MJ primary
|
1210.53
|
Mineral extraction
|
MJ surplus
|
3.70
|
Figure 7 shows the contribution of inputs to total emissions in each impact category of one ton cantaloupe production.
According to Fig. 7, direct emissions had the most environmental effects in most categories. Direct emissions and indirect emissions from diesel fuel, the highest amount of environmental pollution in the category of adverse effects on human health caused by the release of particulate matter (PM) and its constituents (NOx), Sox, NH3) Had. diesel fuel and urea fertilizer also had the greatest impact on global warming, respectively.
Diesel fuel and direct emissions from the use of input inputs also had the highest effects on soil acidification. Acidification describes a process in which the addition of nitrogen lowers soil pH, which can have a variety of direct and indirect effects on plant growth (Clark et al. 2013). During the acidification process, changes in soil pH decrease with the release of carbonates and open cations from the soil (Bowman et al. 2008).
Once these materials are depleted, the clay minerals in the soil can decompose, releasing toxic minerals into the soil (especially aluminum, Al3+). In the long run, acidification can eliminate nitrification and nitrogen uptake by the plant, leading to further accumulation of acidic compounds such as NH4+ and accumulation of undecomposed material (Roelofs et al. 1985).
In general, open acidification through adverse effects on plant rejuvenation, changing the concentration of toxic minerals (e.g., Al3+) or nutrients (e.g., N, P, base cations) in the soil, reduces biodiversity, because plants that can withstand acidic conditions Tolerate are low (Horswill et al. 2008; Stevens et al. 2010).
Direct emissions are caused by the entry of environmental pollutants into the air, soil and water, due to using of fertilizers and chemical toxins, diesel fuel, oil and the respiration of labors. Ammonia causes acidification and atrification of sensitive ecosystems (Nemecek, Reckenholz-Tänikon, and 2011).
The oceans reduce climate change by absorbing carbon dioxide from fossil fuels in the atmosphere, land use change, and so on. It is estimated that during the period 2014 − 2005, about 26% of the total carbon dioxide emissions from human activities were absorbed by the oceans (Le Quéré et al. 2015). Acidification is the ongoing decrease in the pH value of the Earth’s oceans, caused by the uptake of carbon dioxide (CO2) from the atmosphere. The main cause of ocean acidification is the burning of fossil fuels. Most of the carbon dioxide released into the Earth’s atmosphere as a result of burning fossil fuels is eventually absorbed by the oceans, with potentially adverse consequences for marine life. When carbon dioxide dissolves in the ocean, it lowers the pH and makes the ocean more acidic. Most organisms are near the surface, where most pH changes are expected, but deep-sea organisms may also be sensitive to pH changes (Caldeira and Wickett 2003).
Menzi et al. (1997) reported that about 30% of nitrogen is lost in the form of ammonia, which can be reduced with appropriate measures into about 40% -20% (Menzi et al. 1997). The amount of greenhouse gas emissions in the production of each ton of paddy 1166.09 kg of carbon dioxide has been reported (Nabavi-Pelesaraei et al. 2018). In another study, the amount of greenhouse gas emissions in the production process of garlic, rice, corn, wheat and lentils per hectare was reported to be 2997.13, 1798.27, 1888.19, 839.19 and 149.85 kgCO2eqha− 1 (Pokhrel and Soni 2019).
Mousavi-Avval et al. (2017) Study of energy and economic analysis and evaluation of environmental life cycle (LCA) of rapeseed production in Mazandaran province (northern Iran) stated that the use of chemical fertilizers, especially nitrogen, played a key role in environmental emissions (Mousavi-Avval et al. 2017).
They stated that chemical fertilizers are one of the main sources of energy consumption and environmental emissions, especially for the categories of global warming, acidification and eutrophication. In other study Hosseini-Fashami et al. (2019) pointed out that diesel fuel had the highest environmental emissions in strawberry production (Hosseini-Fashami et al. 2019).
Figure 8 shows the environmental effects of inputs in four endpoint impact categories including human health, ecosystem quality, global warming and resources. It indicates that diesel fuel consumption has the greatest environmental impact in most categories. It shows the importance of fuel consumption management in agricultural production.
Table 5
Emission of endpoints based on one ton of categories production in the studied area.
Endpoint
|
Unit
|
Quantity
|
Human health
|
DALY[1]
|
0.03
|
Ecosystem quality
|
PDF*m2*yr[2]
|
1855.33
|
Climate change
|
Kg* CO2*eq
|
155.67
|
Resources
|
MJ primary
|
1214.24
|
In the final effect sections, direct emissions from inputs had the highest environmental impact on human health. Indirect emissions from phosphorus and urea fertilizers had the highest impact on ecosystem quality. The most effective factor in climate change was direct emissions from the consumption of inputs, and in the resource sector, diesel fuel had the greatest environmental impact. In the human health and ecosystem quality subjects, the total amount of environmental effects of cantaloupe production was 0.03 DALY and 1855.33 PDF*m2*yr. In the category of climate change, the amount of emissions from cantaloupe production was 155.67 kg CO2eq. The release of fossil fuel CO2 to the atmosphere by human activity has been implicated as the predominant cause of global climate change (Menon et al. 2007). Khanali et al. (2021) in environmental Evaluation of walnut production reported the amount of emissions in categories of human health, ecosystem quality, climate change and resources as 0.005 DALY, 35498.08 PDF*m2*yr, 2364.60 Kg* CO2*eq and 28872.21 MJ primary respectively (Khanali et al. 2021).
Economic Analysis
Based on the results of Table 6, in summer cantaloupe production fields, the gross production value was 42,229.5 $ha− 1. The variable costs were estimated at 1154.5 $ha− 1 and fixed cost was 1487 $ha− 1. The share of fixed costs was calculated more than variable costs. The profit-to-cost ratio and the productivity values were calculated about 1.6 and 7.27, respectively which means that for every dollar spent in summer cantaloupe fields, it produced 7.27 kg of cantaloupe production.
Table 6
Analysis of economic indicators for summer cantaloupe production
index
|
unit
|
Amount
|
Yield
|
Kgha− 1
|
19255
|
Average selling price
|
$Kg− 1
|
0.22
|
Gross value
|
$ha− 1
|
4229.5
|
Variable costs
|
$ha− 1
|
1154.5
|
Fixed costs
|
$ha− 1
|
1487
|
The total cost of a production period
|
$ha− 1
|
2641.5
|
gross revenue
|
$ha− 1
|
3075
|
net income
|
$ha− 1
|
1588
|
Benefit to cost ratio
|
Dimensionless
|
1.6
|
Efficiency
|
Kg$
|
7.27
|
Sharifi (2018) In reported that diesel fuel input (0.90%) had the highest cost share in melon production. Machinery, chemical fertilizers, farmyard manures and irrigation were also significant at the 1%. They stated that a 1% increase in the independent variables would result in a 0.12%, 0.38%, 0.13%, and 0.73% increase in yield, respectively. The results of their research showed that the variables of diesel fuel and chemical insecticides were significant with a coefficient of 0.90% and 0.19% at the level of 0.05%, respectively, and human labor and seed had no significant effect on crop yield. he stated that in melon production, the effect of indirect energy with a regression coefficient of 0.53% was more than direct energy with a regression coefficient of 0.52% and at the level of 0.01% was significant. Also reported that the regression coefficient of renewable energy (0.58%) and non-renewable energy (0.50%) were significant at the level of 0.01% (Sharifi 2018).
[1]. DALY: An emission of 1 is equivalent to: lack of 1 life year of 1 personal, or 1 person suffers 4 years from an inability with a weight of 0.25.
[2]. PDF*m2*year: An emission of 1 is equivalent to disappearing of all species from 1 m2 throughout 1 year, or vanishment of 10% of species from 1 m2 throughout 10 years, or vanishment of 10% of species from 10 m2 throughout 1 year.