Roots distribution, yield and protein content of broad bean (Vicia faba L. major) treated with different tillage methods in southern Italy

Abstract

This research was carried out at Foggia (southern Italy) on a silty-clay soil (Typic Chromoxererts) in an experimental field characterized by hot-arid summers, cold winters and scanty and sporadic rains.Roots distribution, agronomic parameters and nitrogen balance were recorded at harvest of broad beans after durum wheat in a two-year rotation. Four different tillage methods (A — traditional mouldboard ploughing; B — ripper subsoiling; C — skim ploughing; D — minimum tillage) and three N rates (0, 50, 100 kg N ha−1 only to wheat) were used. Nitrogen balance in selected “treatment” was done by comparing soil mineral nitrogen variations (N-NO3 + exchangeable N-NH4), in all experimental plots, with nitrogen distribution within broad bean plant organs. The findings show a strong interaction between tillage methods and N rates as affected by the modifications of water infiltration, temperature gradients, organic carbon turnover and soil nitrogen transport and transformations.