Energy balance and environmental impacts of rice and wheat production: A case study in Nepal

Energy and environment are the key concerns in todays’ agriculture. This study investigated energy balance and environmental impact of rice and wheat production systems in terms of energy ratio, impact of energy inputs to the crop yield and CO2e (carbon dioxide equivalent) emissions under terai and hill geographical regions of Nepal. Primary data were collected from 139 randomly selected farms by using structured questionnaire. The results revealed that the total energy consumption in rice and wheat production were 9.70 GJ/hm2 (terai) to 11.78 GJ/hm2 (hill) and 8.40 GJ/hm2 (hill) to 10.95 GJ/hm2 (terai), respectively. The energy balance of rice and wheat production were found 46.33 GJ/hm2 (hill) to 59.29 GJ/hm2 (terai) and 27.14 GJ/hm2 (terai) to 38.52 GJ/hm2 (hill), respectively, where energy use efficiency in terai and hill were found to be 7.14 and 4.97 in rice, and 3.49 and 5.59 in wheat, respectively. The contribution of fertilizer on impacts was significant among other energy inputs in rice and wheat production in both geographical regions. The CO2e emissions from rice and wheat were higher by 52% and 78% in hill as compared to respective crop rice (1786 kg CO2e/hm2) and wheat (843 kg CO2e/hm2) in terai. This study showed that rice production system in terai is more energy and environmentally efficient, whilst wheat production in hill is more energy efficient.