Energy efficiency of organic pear production in greenhouses in China
2010
Liu, Yuexian | Høgh-Jensen, Henning | Egelyng, Henrik | Langer, Vibeke
The development of organic protected cultivation taking place in densely populated areas has raised the question whether it is an environmentally friendly production system. The present study investigated energy consumption of organic pear production in two production systems, namely in traditional Chinese solar greenhouses and in the open field. In both production systems, energy output/input ratio and energy productivity were used as indicators to determine the energy efficiency; yield, cost of production, net economic return per land area unit and benefit/cost ratio were used to evaluate economic productivity. The analysis results indicated that energy input and energy output per land area unit in the solar greenhouse were higher than in the open field; whereas energy efficiency in terms of output/input ratio and energy productivity were lower in the solar greenhouse than those in the open field. However, if energy input sequestered in the protected structure was excluded in the solar greenhouse production system, energy efficiency was higher in the greenhouse system than in the open-field system. Our analysis further showed that the economic costs, the yield, cost of production, gross product value and net income per land area unit in the greenhouse were more than twice as high as those in the open field due to a higher tree density and a premium price. However, the production taking place in the open field used a great share of renewable energy and higher energy efficiency, which may comply more with the principles of organic farming than the greenhouse production system.
显示更多 [+] 显示较少 [-]