A source-wise and operation-wise energy use analysis for corn silage production, a case study of Tehran province, Iran

This study aims at finding the input–output energy use and the relationship between energy input levels on yield in southern part of Tehran province, Iran. Besides, the energy analysis was carried out based on different farm operations. Data were collected from 40 corn silage (as animal feed) farms, using face to face questionnaire method. The total energy input consumption was 36.5 GJ ha−1; in which chemical fertilizers with 11.8 GJ ha−1(with 32.3%), followed by diesel fuel and water for irrigation (with 26.5% and 24.9%, respectively) were highly contributed to the total energy use. Energy ratio, energy productivity, specific energy and net energy indices were 3.49, 1.45 kg MJ−1, 0.69 MJ kg−1 and 90563.3, respectively. The operation-wise analysis showed that land preparation and plant protection operations had significantly high energy consumption (4224.6 and 2446.0 MJ ha−1, respectively). The econometric results revealed that chemical fertilizers, fuel, water, human labor had a positive impact on output level. Moreover, as a result of this study, corn silage production has experienced a substantial increase in non-renewable energy use. Additionally, land preparation, planting and post-harvest operations were used in excess.