1. Department of Agricultural Economics and Rural Development, University of Goettingen, 37073 Goettingen, Germany;
2. Center of Biodiversity and Sustainable Land Use (CBL), University of Goettingen, 37073 Goettingen, Germany
3. Faculty of Economics and Management, Bogor Agricultural University (IPB University), Bogor 16680, Indonesia
4. Department of Ecology of Tropical Agricultural Systems, University of Hohenheim, 70599 Stuttgart, Germany
5. Department of Crop Sciences, University of Goettingen, 37073 Goettingen, Germany