Introduction

Persimmon is a fleshy fibrous tropical, deciduous fruit belonging to Ebenaceae family. It is commonly cultivated in warm regions of the world including China, Korea, Japan, Brazil, Turkey, and Italy (Itamura et al. 2005; Yokozawa et al. 2007). While persimmon (Diospyros kaki L.) is known as “Trabzon persimmon” in Turkey, it is also known as “Asian” or “Japanese apple” in South America (Çelen 2019; Karakasova et al. 2013).

Diospyros sp., to which persimmon is a member, includes approximately 400 varieties, most of them are found naturally in tropic and subtropical climate zones and only 4 varieties are commercially grown (Spongberg 1977; Kitagawa and Glucina 1984; Erdoğan et al.).

Persimmon fruit contains 79% water, 0.7% pectin, 0.4% protein, and crude fiber (Radha and Mathew 2007). Vitamin C contents vary from 7.5 to 70 mg per 100 g (1 oz = 28.34952 g) of the fruit flesh depending upon the variety (Kondo et al. 2004). Some varieties are as rich as satsuma mandarin and strawberry in their vitamin C contents (Nakagawa et al. 2008). It also contains various bioactive substances (Table 1) like vitamins (A, B complex, C, E, and K) and minerals (zinc, copper, iron, magnesium, calcium, and phosphorus) that are valuable for the proper physiology of human health (Shazia et al. 2016; USDA 1998). Proanthocyanidins (PAs) are potent antioxidants and show 20 and 50 times more activity than vitamins C and E, respectively (Kawase et al. 2003).

Table 1 Nutritional value per 100 g (3.5 oz) of persimmon fruit (Diospyros kaki, raw)
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According to 2014 data, the total amount of persimmon production in the world was 5,190,624 tons and the biggest producers were China (3,803,564 tons), Korea (428,363 tons), Spain (245,000 tons), Japan (240,600 tons), Brazil (182,290 tons), Azerbaijan (140,405 tons), Italy (39,149 tons) (Anonymous 2020b). Turkey’s total persimmon production was 38,043 tons in 2017 and production was mostly in Adana (9100 tons), Izmir (4179 tons), Mersin (3403 tons) Hatay (3172 tons) and Adıyaman (2991 tons) provinces. The persimmon growing area in Adıyaman (197.5 ha) makes up approximately 8.2% of the total persimmon production area in Turkey (2393.2 ha) and the production amount makes up around 7.9% of the total production (TUIK 2018).

Energy analysis of agricultural production is a significant approach for the classification and definition of the agricultural systems in terms of energy consumption (Sabah 2010; Karaağaç et al. 2019). Energy efficiency improvement is a key indicator for sustainable energy management; for enhancing the energy efficiency it must be attempted to increase the production yield or to conserve the energy input without affecting the yield level. Intensive energy consumption as well as reducing the known energy resources is the key factor to develop the philosophy of optimum energy consumption. Optimum use of energy helps to achieve increased production and contributes to the economy, profitability and competitiveness of agricultural sustainability of rural communities (Singh Singh et al. 2004; Mousavi-Avval et al. 2011). A greenhouse gas (GHG) is a gas in the atmosphere that absorbs and spreads radiation within the thermal infrared range. The greenhouse gas (GHG) emissions of agriculture come from several sources such as machinery, diesel fuel, chemical fertilizers, chemicals and electricity. So, the rise in energy inputs can cause a rise in the greenhouse (GHG) emissions in agricultural action (Nabavi-Pelesaraei et al. 2016).

Many studies were done on energy efficiency in several types of agricultural products. such as on energy efficiency activities of almond (Beigi et al. 2016), apple (Aydın et al. 2019; Çelen et al. 2017), olive (Gökdoğan and Erdoğan 2018), pear (Aydın et al. 2017), vetch (Baran 2017), walnut (Baran et al. 2017), groundnut (Baran et al. 2019), nectarine (Oğuz et al. 2019), citrus (Yilmaz and Aydin 2020), mandarin (Karabat and Aydın 2018). Several studies on greenhouse gas emissions were done on horticulture crops such as olive (Rajaeifar et al. 2014), nectarine (Qasami-Kordkheili and Nabavi-Pelesaraei 2014), peach (Nikkhah et al. 2017), pomegranate (Özalp et al. 2018), apple (Taghavifar and Mardani 2015), watermelon (Nabavi-Pelesaraei et al. 2016), grape (Mardani and Taghavifar 2016), strawberry (Khoshnevisan et al. 2013) and different fruits (Eren et al. 2019).

Although many experimental studies were defined on energy balance on agriculture, there was no study on the energy use efficiency and greenhouse gas emissions (GHG) of persimmon production in Turkey. In this study, it has been aimed to define the energy use efficiency and greenhouse gas emissions (GHG) of persimmon production in Adıyaman province in Turkey.

Materials and Methods

Description of the Study Area

Southern part of the Adıyaman province is hot and dry during summer months and rainy and cold during winter months. Central Adıyaman is located at 37° 45′ north latitude and 38° 16′ eastern longitude. Adıyaman’s elevation from sea level is 672 m. The daily difference between highest temperature and lowest temperature is about 10 °C (Anonymous 2016). This research has been performed for 2017–2018 production season in Adıyaman province of Turkey in dry conditions in 2018. The data supplied from research have been collected from 72 different farms by face to face surveys with simple random sampling method proposed by Çiçek and Erkan (1996). In the formula (1) n : is the required sample size; N : the number of total enterprises in the area; s, standard deviation; t: the reliability coefficient (1.96 which represents 95% confidence); d: acceptable error (5% deviation). The acceptable error value has been defined to be 5%, and the sample size has been computed as 72 farms, to achieve 95% reliability.

$$ n = \frac{N\times s^{2}\times t^{2}}{\left(N-1\right)d^{2}+\left(s^{2}\times t^{2}\right)}$$
(1)

By calculating the agricultural input energies and output energies were used in persimmon production and the energy use efficiency was determined. Human labour energy, machinery energy, farmyard manure energy, chemical fertilizers energy, chemicals energy Electricityity energy, irrigation energy and diesel fuel energy were computed as inputs and yield was computed as output.

The units shown in Tables 2 and 3 are the inputs of persimmon production. Previous energy balance and greenhouse gas emissions (GHG) studies were evaluated when defining the energy equivalent and greenhouse gas emissions (GHG) coefficients.

Table 2 Energy equivalents in agriculture production
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Table 3 Greenhouse gas (GHG) emissions coefficients in persimmon production
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The total energy equivalent was computed by adding energy equivalents of all inputs in MJ unit. In order to compute the energy input-output in persimmon production, energy use efficiency, energy productivity, specific energy and net energy were computed by using the following formulates (Mandal et al. 2002; Mohammadi et al. 2008, 2010).

Koçtürk and Engindeniz (2009) reported that, the input energy is also classified into direct and indirect, and renewable and non-renewable forms. The indirect energy consists of pesticide and fertilizer, while the direct energy includes human and animal labour, diesel and Electricityity used during the production process. On the other hand, non-renewable energy includes petrol, diesel, Electricityity, chemicals, fertilizers, machinery, while renewable renewable energy consists of human and animal labour (Mandal et al. 2002; Singh et al. 2003).

$$\text{Energy use efficiency}=\text{Energy output }(\mathrm{MJ}\mathrm{ha}^{-1})/\text{Energy input }(\mathrm{MJ}\mathrm{ha}^{-1})$$
(2)
$$\text{Energy productivity}=\text{Yield output }(\mathrm{kg}\mathrm{ha}^{-1})/\text{Energy input }(\mathrm{MJ}\mathrm{ha}^{-1})$$
(3)
$$\text{Specific energy}=\text{Energy input }(\mathrm{MJ}\mathrm{ha}^{-1})/\text{Yield output }(\mathrm{kg}\mathrm{ha}^{-1})$$
(4)
$$\text{Net energy}=\text{Energy output }(\mathrm{MJ}\mathrm{ha}^{-1})-\text{Energy input }(\mathrm{MJ}\mathrm{ha}^{-1})$$
(5)

Energy use efficiency was conducted by using Microsoft Excel program; before, the results were tabulated Table 4 and related to persimmon production input-output values and the relevant calculations were provided in Table 4. Energy efficiency calculations in persimmon production were given in Table 5, energy inputs in the forms of energy for persimmon production were given in Table 6.

Table 4 Energy input-output in persimmon production
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Table 5 Energy efficiency calculations in Persimmon production
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Table 6 Energy inputs in the forms of energy for Persimmon production
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Greenhouse gas (GHG) emissions of inputs in persimmon production were given in Table 7. The greenhouse emissions (GHG) (kg CO2‑eqha−1) united with the inputs to growing 1 ha of persimmon were calculated as following, adapted by (Hughes et al. 2011).

$$\mathrm{GHG}_{ha}={\sum }_{i=1}^{n}R\left(i\right)xEF\left(i\right)$$
(6)
$$I_{\mathrm{GHG}}=\frac{\mathrm{GHG}_{ha}}{Y}$$
(7)
Table 7 Greenhouse gas (GHG) emissions in persimmon production
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∑ Where R(i) is the application rate of input, I (unitinputha−1), and EF (i) is the GHG emission coefficient of input i (kg CO2‑equnitinput−1). Table 3 is the GHG emissions coefficients of agricultural inputs. However, an index is determined to evaluate the amount of emitted kg CO2‑eq per kg yield as following adapted Houshyar et al. (2015) and Khoshnevisan et al. (2014). IGHG is GHG ratio, and Y is the yield as kg per ha.

Results and Discussion

During the studies in the persimmon producers, the average amount of persimmon produced per hectare for 2018 production seasons was computed as 39200 kg. As it can be seen in Table 4, energy inputs in persimmon production were as follows, respectively: 20,950.42 MJ ha−1 (44.04%) chemical fertilizers, 6370.74 MJ ha−1 (13.39%) chemicals energy, 5200.08 MJ ha−1 (10.93%) human labour, 3479.76 MJ ha−1 (7.31%) machinery energy, 3376.80 MJ ha−1 (7.10%) electricity energy, 3029.48 MJ ha−1 (6.37%) diesel fuel energy, 2608.20 MJ ha−1 (5.48%) irrigation water energy and 2556.00 MJ ha−1 (5.37%) farmyard manure energy. Total input energy was computed as 47,571.48 MJ ha−1. Production output persimmon yield was computed as 74,480.00 MJ ha−1.

Persimmon yield, energy input, energy output, energy efficiency, specific energy, energy productivity and net energy in Persimmon production were computed as 39200 kg ha−1, 475,571.48 MJ ha−1, 74,480.00 MJ ha−1, 1.57, 1.21 MJ kg−1, 0.82 kg MJ−1 and 26,908.52 MJ ha−1, respectively (Table 5). In previous agricultural studies, Kaltsas et al. (2007) determined (organic olive) energy output/input ratio as 3.31, Gündoğmuş (2006) determined (organic apricot) energy output/input ratio as 1.45, and Gökdoğan et al. (2017) determined (organic mulberry) energy output/input ratio as 5.62, Beigi et al. (2016) determined (walnut) energy output-input ratio as 0.62–1.12, Baran et al. (2017) determined (walnut) energy output-input ratio as 0.61 and Gökdoğan and Erdoğan (2018) determined (olive) energy output-input ratio as 2.72.

The consumed total energy input in persimmon production was classified as 29.88% direct, 70.12% indirect, 21.79% renewable and 78.21% non-renewable (Table 6). Similarly, in previous agricultural studies, almond (Beigi et al. 2016), walnut (Baran et al. 2017), olive (Gökdoğan and Erdoğan 2018) the ratio of non-renewable energy was higher than the ratio of renewable energy.

The results of greenhouse gas (GHG) emissions of persimmon production were tabulated in Table 7. The total GHG emissions were calculated as 4440.00 kg CO2‑eqha−1. The results of the study showed that the share of human labor in total GHG emissions was the highest (1857.17 kg CO2‑eqha−1), chemical fertilizier (1698.85 kg CO2‑eqha−1) and herbicide (1177.35 kg CO2‑eqha−1) held the second and third. GHG ratio (per kg) was determined as 0.18. In similar a study, (Taghavifar and Mardani 2015) calculated the total GHG emission of apple production as 1200 kg CO2‑eqha−1, (Özalp et al. 2018) calculated the total GHG emission of pomegranate production as 1730 kg CO2‑eqha−1 and (Mardani and Taghavifar 2016) calculated the total GHG emission of grape production as 860 kg CO2‑eqha−1.

Conclusion

As a result, in this study, the energy efficiency of persimmon production was determined. According to the results, the profitability of persimmon production was determined to be low in terms of energy efficiency (1.57). The energy inputs in persimmon production were computed, respectively, as 20,950.42 MJ ha−1 (44.04%) chemical fertilizers, 6370.74 MJ ha‑1 (13.39%) chemicals energy, 5200.08 MJ ha−1 (10.93%) human labour energy, 3479.76 MJ ha−1 (7.31%) machinery energy. Total input energy was computed as 47,571.48 MJ ha−1. Energy values of yield were computed as 74,480.00 MJ ha−1. Energy use efficiency, specific energy, energy productivity and net energy calculations were computed respectively as 1.57, 1.21, MJ kg−1, 0.82 kg MJ−1 and 26,908.52 MJ ha−1. The consumed total energy input in persimmon production can be classified as 29.88% direct, 70.12% indirect, 21.79% renewable and 78.21% non-renewable. Farmyard manure should be used instead of the chemical fertilizers in order to increase the energy use efficiency and renewable energy ratio in persimmon production. The total greenhouse gas (GHG) emissions were determined as 4440.00 kg CO2‑eqha−1 and 0.18 of GHG ratio (per kg). The results of the study showed that the share of human labor in total GHG emissions was the highest (1857.17 kg CO2‑eqha−1), chemical fertilizier (1698.85 kg CO2‑eqha−1) and herbicide (1177.35 kg CO2‑eqha−1) held the second and third. Energy use efficiency and GHG emissions were increased because the usage of farmyard manure was used instead of chemical fertilizers. Çelen (2016) reported that reducing the usage of nitrogen by lowering erosion, leakage, and evaporation, using more bio-nitrogen, using farmyard manure and other bio-fuels, implementing waste and left-over management in harvest residues and having minimum soil processing are compulsory.