1. Kiel University Institute of Plant Nutrition and Soil Science Hermann-Rodewald-Straße 2 24118 Kiel Germany
2. University of Khartoum Department of Agronomy, Faculty of Agriculture 13314 Shambat, Khartoum North Sudan
3. Georg-August-University of Göttingen Department of Crop Sciences, Plant Nutrition Carl-Sprengel-Weg 1 37075 Göttingen Germany
4. Duy Tan University Institute of Research and Development 03 Quang Trung Da Nang Vietnam
5. RIKEN Center for Sustainable Resource Science, Tsurumi Stress Adaptation Research Unit 230-0045 Yokohama Japan