Iodine (in both forms) was applied pre-sowing in a dose of
2 kg I ha1 as pure salts (KI – POCH Poland, KIO3 – Sigma Aldrich).
Nitrogen in the form of Ca(NO3)2 [Yara International ASA (Hydro)]
and (NH4)2SO4 [Zakłady Azotowe in Tarnów, Poland] was introduced
in two 100 kg N ha1 doses: pre-sowing and as a top-dressing.