REGULAR ARTICLE Does genotypic variation in nitrogen remobilisation efficiency contribute to nitrogen efficiency of winter oilseed-rape cultivars (Brassica napus L.)? Abdullah Ulas & Torsten Behrens & Franz Wiesler & Walter J. Horst & Gunda Schulte auf ’m Erley Received: 21 November 2012 / Accepted: 13 March 2013 / Published online: 12 April 2013 # Springer Science+Business Media Dordrecht 2013 Abstract Aims Winter oilseed-rape production is characterized by a low N efficiency, due to low N uptake and insuf- ficient N remobilisation to the seeds. In particular, a reduction of leaf N losses might be one way to improve N efficiency of this crop. It was tested if variations in leaf N losses and in stem residual N amounts at maturity exist between cultivars differing in N efficiency. Methods In a 3-year field experiment, four oilseed rape cultivars were cultivated at limiting, medium, and high N supply. Results N harvest indices in this study were compara- tively high (around 0.79) and leaf N losses amounted to at most 13 kg N ha -1 . 86 % of the leaf N present at the beginning of flowering was remobilised, irrespective of N rate or cultivar. Nevertheless, genotypic variation in leaf N loss existed. They were mainly due to differences in leaf N accumulation until flowering. Residual N in stems (up to 33 kg N ha -1 ) was higher than leaf N losses and varied more between treatments but was not related to genotypic variation in yield. Conclusions N uptake after flowering was more im- portant than N remobilisation from vegetative biomass for genotypic variation in seed yield both at low and high N supply. Keywords N partitioning . Leaf N losses . Stem N remobilisation . Post-flowering N uptake . Genotypic variation Introduction Winter oilseed rape is the most important oilseed crop in northern Europe. Rapeseed oil can be used for multiple purposes (edible oil, industrial purposes, bio- diesel, etc.) and the cultivation of this crop is valuable Plant Soil (2013) 371:463–471 DOI 10.1007/s11104-013-1688-y Responsible Editor: Hans Lambers. A. Ulas : T. Behrens : F. Wiesler : W. J. Horst : G. Schulte auf ’m Erley Institute for Plant Nutrition, Leibniz University of Hannover, Herrenhäuser Str. 2, 30419 Hannover, Germany Present Address: A. Ulas Soil Science and Plant Nutrition Department, Faculty of Agriculture, University of Erciyes, 38039 Kayseri, Turkey Present Address: F. Wiesler LUFA Speyer, Obere Langgasse 40, 67346 Speyer, Germany Present Address: G. Schulte auf ’m Erley (*) Institute of Plant Nutrition and Soil Science, Christian Albrechts University Kiel, Hermann-Rodewald Str. 2, 24118 Kiel, Germany e-mail: schulteaufmerley@plantnutrition.uni-kiel.de