Introduction

Energy has a key role in economic and social progress but there is a general lack of rural energy development policies that focus on agriculture (FAO 2008; Rafiee et al. 2010). Efficient use of energy is one of the main demands of sustainable agriculture. Energy use in agriculture has become more intense in response to increasing population, restricted supply of arable land and a desire for higher standards of life. Continuous demand in increasing food production resulted in intense use of chemical fertilizers, pesticides, agricultural machinery, electricity and other natural resources. Efficient use of energy in agriculture will minimize environmental problems, prevent destruction of natural resources and advance sustainable agriculture as an economical production system (Erdal et al. 2007; Omer 2007; Rafiee et al. 2010). The energy balance is defined as the difference between gross energy of useful products divided by non-renewable energies used to produce them (Risoud 2000; Azizi and Heidari 2013). Imposing energy balances could lead to more productive and environmentally friendly crop production (Moreno et al. 2011; Azizi and Heidari 2013).

Today’s agricultural production relies heavily on the consumption of non-renewable fossil fuels. Consumption of fossil energy results in direct negative environmental effects through deliver of CO2 and other combustion gases. Indirectly, there have been positive effects: increased yields and reduced risk. Yet, large amounts of cheap fossil energy have indirect negative impacts on the environment like less various natures through the condensation of agricultural practices (Refsgaard et al. 1998; Gündoğmuş 2006). Effective energy use in agriculture is one of the conditions for sustainable agricultural production, since it ensures financial savings, fossil fuels preservation and air pollution reduction (Pervanchon et al. 2002; Gündoğmuş 2006). The energy input-output analysis are usually made to determine the energy use efficiency and environmental aspects. This analysis will determine how efficient the energy is used (Rafiee et al. 2010).

Different researches have been done on energy use efficiency of fruit products in the World. In this study, twenty fruit products in the literature were evaluated. For example, studies have been done on energy use efficiency analysis of almond (Beigi et al. 2016), apricot (Esengün et al. 2007), apple (Rafiee et al. 2010), banana (Akçaöz 2011), cherry (Kızılaslan 2009), grape (Koçtürk and Engindeniz 2009), kiwifruit (Mohammadi et al. 2010), lemon (Ozkan et al. 2004), mandarin (Ozkan et al. 2004), mulberry (Gökdoğan et al. 2017), nectarin (Qasemi-Kordkheili et al. 2013), orange (Ozkan et al. 2004), peach (Göktolga et al. 2006), pear (Tabatabaie et al. 2013), plum (Baran et al. 2017a), pomegranate (Canakcı 2010), quince (Gündoğmuş 2013), strawberry (Banaeian et al. 2011), sweet cherry (Demircan et al. 2006) and walnut (Baran et al. 2017b). Although many experimental studies have been done on energy use efficiency analysis in fruit field but there is no study on collective (tabulated) energy efficiency evaluation study on fruit production. Energy use efficiency indicators will serve as a collective resource for comparison and assessment purposes during studies to be conducted on energy use efficiency in fruit production.

Materials and Method

In order to evaluate the energy use efficiency of these fruit data have been done literature search. In this study, twenty fruit products have been evaluated in the literature of the World. In fruit energy use efficiency studies, human labour energy, animal labour energy, machinery energy, diesel fuel energy, chemical fertilizers energy, pesticides energy, irrigation energy, farmyard manure energy, organic fertilizers energy and electricity energy have been contained as inputs. Fruit has been contained as output. Total energy in area unit (ha) composed each total of input energy and energy equivalents of all inputs in MJ unit. In order to compute the energy input-output in fruit production, energy use efficiency (energy output/energy input), energy productivity (yield output/energy input), specific energy (energy input/yield output) and net energy (energy output – energy input), in the form of direct and direct, as well as renewable and non-renewable energy have been computed by researchers. In this study, data of these studies have been evaluated, commented and tabulated (Table 1, 2 and 3).

Table 1 Energy use efficiency indicators in fruit productiona,b
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Table 2 Energy consumption in fruit production
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Table 3 Energy input in the form of energy for fruit production
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Results and Discussion

In fruit studies, yield, energy input, energy output, energy use efficiency, energy productivity, specific energy and net energy values have been tabulated (Table 1). It can be seen from these Table 1 that the first, second and third highest energy inputs (MJ ha−1) in fruit studies are strawberry (805,376.30 MJ ha−1), pear (172,608.43 MJ ha−1) and lemon (62,977.87 MJ ha−1), respectively. If the average values are analysed by referring to Table 1, it can be seen that highest yield (kg ha−1) in fruit production are strawberry (64,153.33 kg ha−1), banana 51,592.04 (MJ ha−1) and pear 46,390.59 (MJ ha−1), respectively. The first, second and third highest energy use efficiency in fruit studies are grape (8.64), mulberry (5.62) and pomegranate (2.87), respectively. Grape, mulberry and pomegranate are the most profitable production in terms of energy use efficiency.

It can be seen from these Table 1 that the first, second and third highest energy outputs (MJ ha−1) in fruit studies are strawberry (121,891.33 MJ ha−1), banana (98,024.88 MJ ha−1) and pear (88,142.13 MJ ha−1), respectively. It can be seen from these Table 1 that the first, second and third highest net energy (MJ ha−1) in fruit studies are grape (286,422 MJ ha−1), pomegranate (60,836 MJ ha−1) and banana (46,464.83 MJ ha−1), respectively.

In this study, some energy inputs have been considered, for example; farmyard manure energy (renewable energy), chemical fertilizers, machinery and diesel fuel energy (non-renewable energy) have been tabulated (Table 2). It can be seen from these Table 2 that the first, second and third highest chemical fertilizers energy inputs (%) in fruit studies are walnut (74.40%), pomegranate (57.40%) and quince (52.86%), respectively. The first, second and third highest diesel fuel energy inputs (%) in studies are strawberry (78.30%), grape (33.04%) and orange (31.18%), respectively. Machinery energy consumption in studies is banana (20.58%), plum (12.27%) and grape (10.52%), respectively. In this study, farmyard manure energy consumption (%) is banana (21.78%), apple (17.65%) and apricot (16.03%), respectively.

The distribution of inputs has used for the production of fruit production, in accordance to direct, indirect, renewable and non-renewable energy groups have been given in Table 3. It can be seen from these Table 3 that the first, second and third highest non-renewable energy inputs (%) in fruit studies are grape (97.03%), mandarin (96.08%) and lemon (95.91%), respectively. The highest renewable energy (%) in studies is mulberry production. The consumed total energy input in mulberry production could be classified as (88.10%) renewable and (11.90%) non-renewable. Renewable energy ratio is high, because; mullberry production is organic production. If energy use efficiency is to be increased, farmyard manure and organic fertilizer should be used instead of chemical fertilizers.

When the results have been evaluated, generally, fruit production are profitable production in terms of energy use efficiency (average energy use efficiency: 1.76). Non-renewable energy use is very high in fruit production. Optimization is an important appliance to maximize the amount of productivity which can significantly affect the energy consumption and production costs. Optimization of energy use in agricultural systems is carried out in two ways: an increase in productivity with the existing level of energy inputs or conserving energy without affecting the productivity. Energy management becomes more important when the energy required should be economical, sustainable and productive (Gündoğmuş 2013). According to Demircan et al. (2006), “suitable tractor selection and management of machinery to reduce direct use of diesel fuel (Işık and Sabancı 1991) and precise fertilization management, knowing the correct amount and frequency of fertilization (especially nitrogen) (Kitani 1999) have needed to save non-renewable energy sources without impairing the yield or profitability, in order to improve the energy usage efficiency of sweet cherry production”. For decrease of inputs (machinery and diesel fuel) of fruit production, these advices may perform for fruit production. Additionally, farmyard manure and organic fertilizer should be used instead of chemical fertilizers to reduce non-renewable energy.