Abstract
For estimation of energy use efficiency for sweet potato production in the riverbank areas of Bangladesh under subtropical climatic conditions, a study was conducted with sweet potato producers of the respective areas from 60 individuals (12 producers' for each sweet potato variety) by using a structural questionnaire. The results revealed that the majority of the energy input was consumed by the pre harvest activities (22,313.55 MJ ha(-1) or 90.85%), of which fertilizer application (36.84%) and irrigation (35.24%) consumed the most energy input, whereas only 9.15% (2,248.42 MJ ha(-1)) consumed by the post-harvest activity for sweet potato production. The energy input involved in the production system was similar to the direct (12,149.76 MJ ha(-1) or 49.47%) and indirect (12,412.21 MJ ha(-1) or 50.53%) sources, while it was much higher in non-renewable sources (22,884.21 MJ ha(-1) or 93.17%) with a minimum of (1,677.76 MJ ha(-1) or 6.83%) from renewable sources. The average energy use efficiency, energy productivity, specific energy, net energy, energy profitability and water-energy productivity of orange -fleshed sweet potato (OFSP) varieties 4.36, 1.22 kg MJ(-1), 0.83 MJ kg(-1), 82,511.73 MJ ha(-1), 3.36 and 1.32 g m(-3) MJ(-1), respectively. The OFSP varieties showed better performance in respect of all the energy and water use indicators.