Microorganisms and its potential as bioinputs in the production of olive seedlings

Abstract

The inoculation with beneficial microorganisms has been demonstrated an interesting potential for improving plant growth from various crops in southern Brazil. However, in olive orchards, where the naturally acid soils are limed to higher pH values than most of the crops, the potential of the inoculation with beneficial microorganisms is still a gap. The present study investigated the effect of inoculations (without inoculation, inoculation with the bacterium Azospirillum brasilense, inoculation with the fungus Trichoderma harzianum and Trichoderma virens) at three levels of soil liming (targeting pH-H2O of 5.0, 6.0 and 7.0) on the root growth of olive seedlings. Inoculation of the fungus Trichoderma harzianum promoted greater length and surface area of the roots of plants grown in acidic soil. In contrast, at the highest liming level, all tested microorganisms contributed to significant increases in these important root growth parameters, with an average increase of 49% in root length and 35% in the root surface area compared to the treatment without inoculation. These results suggest that the association of a soil pH favorable to olive growing with the use of microorganisms as bioinputs can improve the productive potential of the olive tree in regions outside their native habitat.