Effects of Sewage Sludge Originated from Urban Waste Water Treatment Plant on Growth of Freesia Spp. and Some Properties of Soil

In this study, the effects of sewage sludge on selected soil properties with possible uses of agricultural purpose were determined. Amount of sewage sludge for application was determined based on environmental concern and regulations. For this purpose, a two-year greenhouse experiment (2004-2006) was conducted on a randomized plots experimental design with four replications. Sewage sludge was applied to pots with amount of 0, 30, 60, 90 and 180 t ha-1. After 7 days of sewage sludge application, treatments were applied to each pot were: (i) NPK fertilizer (50 mg NPK kg-1), (ii) planting Fressia spp. round, (iii) irrigation (in field capacity). In sewage sludge applied soil, soil properties (moisture, EC, pH, CaCO3, organic matter, CEC, total N, available P, exchangeable K, total and exchangeable Cd, Ni, B, Pb, Cr and Zn) were measured. In conclusion, AS amount of sewage sludge treatment increased, values of EC, pH, CaCO3, organic matter, CEC, available P, exchangeable K also increased (P 0.05). There was significant difference between all sewage sludge applications (30, 60, 90 and 180 t ha- 1) and control application (0 t ha-1) in total N content of soil (P 0.01). Although total Pb and Cd content of soil increased with increasing sewage sludge application doses, their content were under safety limit for control regulations of soil pollution in below pH 6 level in soil. Total Cd, Ni, Zn and B content of the soil increased compared to control treatments; however, their contents were not significantly different soil amount treatments. Increasing doses of sewage sludge affected to growth of Freesia spp. and increased selected growth parameters such as number of flower, diameter of rhizome, number of regenerated infant rhizome compared to control treatments.