عنوان مقاله [English]
Pistachio (Pistacia vera L.) is one of the most important export crops of Iran which has an important role in non-petroleum exports and has over $800 million benefit per year. However, production of this crop faces many problems in main production centers, especially in energy efficiency and productivity. The pistachio is a native crop of Iran and Syria. The major producers of pistachio are Iran 55%, America 20%, Turkey 10%, Syria 9% and the other countries with 6%. Iran is the major producer of pistachio in the world with more than 60 % of global exports. Kerman Province with more than 270,000 ha under cultivation produces 77 percent of this crop. Moreover, Zarand county with more than 45,000 ha under cultivation plays a major role in the production of pistachio.
Energy flow is one of the topics of agro-ecology in the world and energy output to input ratio is calculated in various agro-ecosystems. One of the indicators of agricultural development is energy flow. So, different studies in the world have been done to evaluate the energy efficiency in the agro-ecosystems. Studies on apricot (Armeniaca vulgris Lam.) showed that energy efficiency can increase with appropriate management practices with minimum dependence on non-renewable energies.
Energy consumption is divided into two parts in agriculture: direct and indirect energy. Direct energy is the fuel, machinery, electricity, energy required for cooling, heating, and lighting. Indirect energy includes the energy used in the production of fertilizers, seed production, machinery, and pesticides. Energy efficiency is an important factor in increasing productivity, especially in agricultural economy of developing countries. Although, many studies have been carried out on energy consumption in the agricultural systems, the analysis of the energy input required to produce pistachio is very low.
Therefore, the objectives of the present study were to determine the input and output energy rates, energy use efficiency, and other energy-related factors in the production of pistachio in Zarand county of Kerman province.
Materials and methods
This research was conducted in the spring of 2011 in the county of Zarand. Zarand is located in the northwestern province of Kerman. In this study, some producers were selected and primary information was collected using questionnaire directly. All data (input and output) were converted to energy equivalent quantities and then energy efficiency was calculated. Random sampling was done in gardens within whole population and sample size was determined by Ozkan et al. (2004):
Where n is the required sample size, N is the number of holdings in target population, s: standard deviation, t is the reliability coefficient (1.96 which represents the 95% reliability) and d is permissible error (5%).
Basic information on energy inputs and pistachio production were transferred into Excel spreadsheets, and analyzed. Based on the energy equivalents of the inputs and output (Table 1), the energy ratio or energy use efficiency, energy productivity and net energy were calculated:
Energy efficiency= Energy input (MJ. ha-1) / energy output (MJ. ha-1)
Energy productivity= Energy input (MJ. ha-1) / pistachio production (kg. ha-1)
Net energy= Energy input (MJ. ha-1) - Power output (MJ. ha-1)
Results and discussion
The results showed that total input energy for Pistacia vera L. production was 119423 MJ. ha-1, whereas total output energy was 40950 MJ. ha-1. Energy efficiency, energy productivity, and net energy were 0.34, 0.012 kg.MJ-1 and -78474 MJ.ha-1, respectively. The highest input energies were related to electricity (45%) and fossil fuels (20%) which had the highest effect on decreasing energy efficiency. Economically, the total cost of Pistacia vera L. production per hectare was 57469600 and the net benefit was 6253040 Rials.
It was concluded that extending proper agricultural management and sustainable exploration of natural resources can enhance energy consumption efficiency in Pistacia vera L. production. Moreover, due to the shortage water and the critical situation of the aquifers in this region, city regional water management should consider measures to reduce water consumption and improve the distribution of water between the farmers to help the sustainability of the aquifers and more efficient production.