Energy flow analysis in agriculture; the case of irrigated pistachio production in Greece

Pistachios (Pistacia vera L.) are among the most energy intensive crops. Therefore, in this study an energy flow analysis was performed to evaluate energy performance of irrigated pistachio production in Greece and identify the most energy consuming phases. Detailed data from on-site surveys were collected from 36 pistachio orchards located in Aegina island during the period 2012-2016. Results showed that the total input energy used for irrigated pistachio production was 41.9 GJ ha−1, whereas the ratios of energy use efficiency and energy productivity were estimated as 70% and 0.06 kg MJ−1, respectively. Nutrient management, irrigation and use of machinery for agricultural operations were the most critical inputs for pistachio production in terms of energy consumption. Additionally, results of econometric analysis indicated that among exogenous inputs analysed in terms of energy performance, fertilizers and machinery had statistically significant positive effects and contributed most to increased yield of pistachios. Based on the overall results of this study, several opportunities for improving energy efficiency and conservation can be identified, including reduction or/and efficient application of chemical fertilizers, water savings, proper use of agricultural machinery, reuse of crop residues for compost production and shifting from fossil fuels to renewable sources of energy.