EFFECT OF HUMIC ACIDS ON GROWTH AND NITROGEN UPTAKE OF CONTAINER-GROWN OLIVE (OLEA EUROPAEA L. ‘MAURINO’)

The effects of humic acid on growth and biomass partitioning in container-grown ‘Maurino’ olive was investigated using the commercial VMO3S. Three humic acid supplies were tested (0, 200, and 1 000 mg/pot/month), combined with fertilizing treatments. The humic acid supplies increased the root/top ratio as well as thin root production. The effects of humic acid on total dry matter production depend to a large extent on the duration of the supply. In this regard, the role of humic substances on nitrogen uptake appears to be fundamental.