1. Natural Resources Institute, University of Greenwich , Central Avenue, Chatham Maritime, Kent ME4 4TB , UK
2. Centre for Crop Systems Analysis, Wageningen University & Research , P.O. Box 430, 6700 AK, Wageningen , the Netherlands
3. Van Hall Larenstein - University of Applied Sciences , Agora 1, 8934 CJ, Leeuwarden , the Netherlands
4. Taiwan Agricultural Research Institute, Council of Agriculture , 189 Zhongzheng Rd, Wufeng District, Taichung City 413008 , Taiwan