In spring, 'blue max' yield increased linearly with N rete to 10.4 t.ha-1, whereas the highest 'Vates' yield (7.0 t.ha-1) was obtained with 112 kg N/ha, and yield increased linearly with N rate to 10.4 t.ha-1, whereas the highest 'Vates' yields were highest (14.5 and 9.9 t.ha-1, respectively) with additional N.