Figure 5.

Agronomic efficiency of N fertilizer (A), apparent nitrogen recovery (B), the nitrogen harvest index (C) and N content in fallen leaves (D) of plants harvested at T2 (G5 stage). Plants were cultivated in lysimeters with 60 (60 N) or 160 kg of N ha⁻¹ (160 N) and supplied with or without Si (12 kg of SiO₄ ha⁻¹; 60 N + Si, 160 N + Si). Values correspond to the mean ± SE for n = 3. The data obtained from plants treated with silicon (60 N + Si and 160 N + Si) were compared to their respective controls (60 N and 160 N). * indicates a significant difference at p ≤ 0.05 and different letters indicate significant difference between treatments at p ≤ 0.05.