The phytotoxicity potential of olive processing waste on selected weeds and crop plants

The effect of sun-dried OPW (olive processing waste) on weeds and crop plants, was investigated at the Adnan Menderes University Research and Application Farm between 2006 and 2007. Sun-dried OPW was placed in pots in doses of 9, 18, 27, 36, 45 and 54 grams per pot, which is equivalent to doses of 1, 2, 3, 4, 5 and 6 kg m⁻²; pots with no OPW served as controls. In these experiments, ten seeds each of wild oat (Avena fatua), sterile oat (Avena sterilis), blackgrass (Alopecurus myosuroides), perennial ryegrass (Lolium perenne), yellow sweetclover (Melilotus officinalis), redroot pigweed (Amaranthus retroflexus), jimsonweed (Datura stramonium), faba bean (Vicia faba), pea (Pisum sativum), and sesame (Sesamum indicum) were sown in pots; for common lambsquarters (Chenopodium album), seedlings were planted in pots. Seedlings of both weeds and crop plants were counted in order to assess the effects of sun-dried OPW on plant emergence. One plant was left per pot for observation of the effects of sun-dried OPW treatments on weed and crop plant growth. The results showed that OPW can be used to suppress the growth of all the weeds listed above, in pots containing V. faba, P. sativum and S.indicum plants and without any negative effects on crop growth.