Preliminary Trials of Field Release of Azospirillum Brasilense as Inoculant in Northern Italy

Summary

Two fields experiments were conducted with Triticum durum during 1985/86 and 1986/87 in northern Italy, to study inoculation effects of homologous and heterologous strains of Azospirillum brasilense.

The results were fairly fluctuating in the two years; in some cases a yield response to inoculation with the homologous strain was detectable, while Azospirillum strain Cd gave almost nihil response in all conditions tested. Soil organic matter content seems to play an important role, i.e. no response to inoculation has ever been obtained at 4%, some effects are just detectable at 3%, while they can be quantified in soils with 1.2–1.5% organic matter. The response to inoculation, when present, consisted in higher (up to 14%) yields, increased weight of root or aerial parts of the plant, higher concentration of Ca, Mg, Mn, Fe in roots or aerial parts of the plant. The persistence of inoculated Azospirilli in soil or rizosphere seems to be short, i.e. few weeks, and differed for the strain used.