RESIDUAL EFFECT OF COMPOSTED OLIVE-OIL MILL SLUDGE ON PLANT-GROWTH

Residual effect of a composted olive oil mill sludge on growth and min eral composition of tall fescue (Festuca arundinacea) was studied. Res ults were compared with those obtained for a mineral fertilizer treatm ent and a control. Compost and inorganic fertilizer had been previousl y applied to two different soils at two rates for five years. The comp ost did not display the phytotoxicity of olive oil mill wastewater, an d produced, at high doses, the highest yield and concentrations of P a nd K in tissue, while decreasing Na, Mn, and Zn assimilability.