OLIVE MILL WASTE COMPOST EVALUATION AS A SOIL AMENDMENT FOR TURFGRASS CULTURE

The increasing demand for high quality sport turfs with intensive usage in conjunction with the depletion and scarcity of traditional soil amendments such as peat necessitates the investigation and evaluation of new materials that could be utilized as soil amendments. A field study examined the effects of olive mill compost soil amendment (OMC) on turfgrass establishment and growth. The OMC comprised of olive leaves, olive-mill wastewater, olive stone and olive pulp and it was uniformly mixed with a sandy loam soil (S) to the whole depth of the profile (0.25 m) at the following proportions: a) 100% soil (S₁) which served as the control, b) S₇:OMC₁ at a proportion of 87.5:12.5 % (v/v), c) S₃:OMC₁ at a proportion of 75:25 % (v/v) and d) S₁:OMC₁ at a proportion of 50:50 % (v/v). Each plot occupied an area of 2 m² and was seeded either with tall fescue (Festuca arundinacea ‘Plantation’) or with bermudagrass (Cynodon dactylon ‘Princess’) at a rate of 50 and 9 g•m-², respectively. Measurements included visual quality ratings, dry weight of the clipping yield, and root dry weight. OMC amendment improved visual quality of tall fescue during establishment and increased the dry weight of the clipping yield. In contrast, tall fescue root growth was reduced in S₁:OMC₁ 3 months after seeding. The visual quality and clipping yield of bermudagrass did not exhibit any significant differences among the treatments. Root dry weight was highest in S₁ and was reduced proportionally to the OMC amendment applied, presumably due to the increased soil moisture retention during winter and early spring.