Articles
THE USE OF COMPOSTED PEAT-SLUDGE MIXTURES IN HORTICULTURAL GROWTH MEDIA
Accumulation of zinc and manganese occurred in roots and shoots of plants raised in media containing sludge.
However, no phytotoxic symptoms were seen in amended media.
No significant differences in leaf lengths or plant heights were evident in tomatoes raised to the first truss.
Fruit from tomatoes raised in growing bags containing media amended with sludge/peat had higher concentrations of zinc and manganese than fruit from plants grown in pure peat media.
However differences were not great, with the highest concentrations of zinc and manganese occuring in fruit from plants raised in media containing 50% composted material, at 32 μg Zn and 23 μg Mn per g dried fruit respectively.
Such concentrations are well below generally accepted toxic levels in plant tissue.
Concentrations of other elements were found to be very low with cadmium in all treatments being less than 0.1 μg.g air dried fruit and lead less than 6 μg.g.
No significant differences in fruit yields were evident between treatments, although yields in growing bags containing 20% (by volume) of composted peat/sludge were marginally superior.