Energy consumption, greenhouse gas emissions and assessment of sustainability index in corn agroecosystems of Iran

- Increasing of energy consumption leaded to decreasing energy use efficiency in corn agroecosystems.
- Total greenhouse gas (GHG) emission as CO2, N2O and CH4 in corn production systems were 2994.66, 31.58 and 3.82 kg ha-1, respectively.
- Global warming potential (GWP) was 12864.84 kg CO2eq ha-1 in corn production systems.
- Sustainability index in corn production systems was 2.05.
- Reducing use of chemicals fertilizer and diesel fuel are necessary for better management of energy flow, global warming potential and environmental crises.

The objectives of this study were to assess the energy flow, greenhouse gas (GHG) emission, global warming potential (GWP) and sustainability of corn production systems in Kermanshah province, western Iran. The data were collected from 70 corn agroecosystems which were selected based on randomly sampled method in the summer of 2011. The results indicated that total input and output energy were 50,485 and 134,946 MJ ha− 1, respectively. The highest share of total input energy in corn production systems was recorded for N fertilizer, electricity power and diesel fuel with 35, 25 and 20%, respectively. Energy use efficiency and energy productivity were 2.67 and 0.18 kg MJ− 1, respectively. Also agrochemical energy ratio was estimated as 40%. Applying chemical inputs produced the following emissions of greenhouse gases: 2994.66 kg CO2, 31.58 kg N2O and 3.82 kg CH4 per hectare. Hence, total GWP was 12,864.84 kg Co2eq ha− 1 in corn production systems. In terms of CO2 equivalents 23% of the GWPs came from CO2, 76% from N2O, and 1% from CH4. In this study input and output C equivalents per total GHG and Biomass production were 3508.59 and 10,696.34 kg C ha− 1. Net carbon and sustainability indexes in corn production systems were 7187.75 kg C ha− 1 and 2.05. Accordingly, efficient use of energy is essential to reduce the greenhouse gas emissions and environmental impact in corn agroecosystems.