1. Institute of Applied Plant Nutrition, University of Göttingen, Carl‐Sprengel‐Weg 1, 37075 Göttingen, Germany
2. Present Address: Department of Soil Science and Plant Nutrition, Harran University, 63200 Şanlıurfa, Turkey
3. Department of Crop Science, Section of Plant Nutrition & Crop Physiology, University of Göttingen, Carl‐Sprengel‐Weg 1, 37075 Göttingen Germany