Energy efficiency in small-scalebiointensive organic onion productionin Pennsylvania, USA

Modern agriculture relies heavily on fossil energy for food production. Reducing fossil energy and replacing that energywith renewable energy is critical in attaining a sustainable food system. Hand-scale intensive food production offers areduction in fossil energy and an increased use of renewable human-based energy. Using biointensive productiontechniques, onions (Allium cepa) were grown in Pennsylvania, USA. A life-cycle analysis was performed to monitor energyutilization. Individual human labor tasks were evaluated using the factor method. This method accounts for the type andduration of physical activity. The average yield of eight onion varieties utilizing biointensive production in standard-sizedbeds (9.3m2;100 ft2) was 160.2 kg. The US average for mechanical onion production is 46.1 kg/9.3m2 (100 ft2). The energyefficiency ratio, specific energy and energy productivity were 51.5, 0.03 MJ kg-1 and 32.2 kg MJ-1 (MJ = megajoule),respectively. When defined within common boundaries, these three relationships: energy input, energy output and yieldproductivity allow researchers, farmers and policy-makers to select production systems and/or practices that better managefossil and renewable energy for food production. Current mechanized agriculture has an energy efficiency ratio of 0.9. Withmost energy being supplied by fossil fuels. The energy efficiency for biointensive production of onions in our study wasover 50 times higher than this value (51.5) and 83% of the total energy required is renewable energy. Biointensiveproduction offers a viable energy use alternative to current production practices and may contribute to a more sustainablefood system