The energy efficiency and economic benefits of agroforestry systems are key issues with respect to their actual sustainability as sound agricultural practices as well as to their potential for further development. Two typical agroforestry systems in China, the Paulownia [Paulownia elongta S.Y. Hu] intercropping system in the north and the Tea [Camellia sinensis O. Ktze] intercropping system in the south were chosen as research subjects. The studies were conducted to establish the energy balance and economic benefits to farmers of these two agroforestry systems in northern and southern China. The objectives were to determine the potential of developing the Paulownia intercropping system in the north and the Tea intercropping system in the south, and their respective sustainability. Two research sites were selected, and two intercropping systems were designed. All the inputs/outputs data of these two agroforestry systems were collected and documented. Input/output analysis and process analysis were conducted. Energy output/input ratio of Paulownia intercropping system was 1.39, of Non-Paulownia intercropping system (traditional cropping system) was 1.27, an increase of 9.45%. Economic output/input ratios of Paulownia and Non-Paulownia intercropping systems were 2.42 and 2.25, respectively, an increase of 7.56%. Ratios under Tea and Non-Tea intercropping systems reflected the same trend. The Tea energy output/input ratio record was 1.12, compared to 0.06 of the Non-Tea intercropping system, i.e. the former is 18.7 times higher than the latter. Economic output/input ratios under Tea intercropping system (2.3) was 64.29% higher than that of the Non-Tea intercropping system (1.4). It was concluded that these two typical agroforestry intercropping systems have a higher energy efficiency and also a better financial benefits to farmers. (c) 2006 Elsevier B.V. All rights reserved.
