The optimization of nitrogen application for root crops such as radish is important not only for yield and product quality (sponginess and hollowness) but also for the environment. Therefore, we evaluated the effect of four levels of N application (0, 150, 300 and 450 mg l-1 N) on three radish cultivars (Saxa, Red Fuoko and White Ghiaccio) grown in pots in autumn/winter (from mid-October to mid...