Energy efficiency of organic pearproduction in greenhouses in China

The development of organic protected cultivation taking place in densely populated areas has raised the question whether itis an environmentally friendly production system. The present study investigated energy consumption of organic pearproduction in two production systems, namely in traditional Chinese solar greenhouses and in the open field. In bothproduction systems, energy output/input ratio and energy productivity were used as indicators to determine the energyefficiency; yield, cost of production, net economic return per land area unit and benefit/cost ratio were used to evaluateeconomic productivity. The analysis results indicated that energy input and energy output per land area unit in the solargreenhouse were higher than in the open field; whereas energy efficiency in terms of output/input ratio and energyproductivity were lower in the solar greenhouse than those in the open field. However, if energy input sequestered in theprotected structure was excluded in the solar greenhouse production system, energy efficiency was higher in the greenhousesystem 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 openfield due to a higher tree density and a premium price. However, the production taking place in the open field used a greatshare of renewable energy and higher energy efficiency, which may comply more with the principles of organic farmingthan the greenhouse production system