OPTIMIZING THE EXTERNAL ENERGY INPUT INTO FARMLAND ECOSYSTEMS - A CASE-STUDY FROM NINGXIA, CHINA

Using models based on production response functions, the optimal amoun t and pattern of energy inputs to three regions of Ningxia Hui Autonom ous Region were calculated, and compared with actual inputs to these a groecosystems. The results suggest that, in order to maximize energy o utput in the Ningxia Plain Region, organic energy input (in particular organic fertilizer) should be greatly increased while in the Middle a nd Southern Region of Ningxia, inorganic fertilizer inputs should be i ncreased. As Ningxia Plain Region has a gl-eater energy conversion eff iciency than the Middle and Southern parts of Ningxia, then, in order to meet regional food requirements, priority should be given to meetin g the future energy requirements of this region. The successful identi fication of optimal energy inputs for Ningxia, suggests firstly that t he methodology may be utilized for analysing other agroecosystems, and secondly that the results may aid decision support in regional planni ng. Copyright (C) 1996 Published by Elsevier Science