Institute of Plant Production and Agroecology in the Tropics and Subtropics, University of Hohenheim, 70593 Stuttgart, Germany

Institute of Plant Production and Agroecology in the Tropics and Subtropics, University of Hohenheim, 70593 Stuttgart, Germany

Institute of Plant Production and Agroecology in the Tropics and Subtropics, University of Hohenheim, 70593 Stuttgart, Germany

current address: Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency – IAEA, Wagramerstrasse 5, 1400, Vienna, Austria

Indonesian Soil Research Institute, Jl. Juanda 98, Bogor 16123, Indonesia

Catholic Relief Services, 228 W. Lexington St., Baltimore, Maryland, USA

World Agroforestry Centre, Jl. CIFOR, Sindang Barang, Bogor, Indonesia

Institute of Plant Production and Agroecology in the Tropics and Subtropics, University of Hohenheim, 70593 Stuttgart, Germany