The effect of olive mill wastewater treated with economic methods on C and N-dynamics in soil

It is generally accepted that the treatment and disposal of olive mill wastewater with high pollution potential as a major environmental problem that must be addressed in all Mediterranean countries. Discharging OMW to the environmental area without any treatment facilities may lead to serious problems due to its high organic matter load, phytotoxic properties and relatively low biodegradability in association with the properties of ecological system and climatic conditions. On the other hand it can be used in agricultural soils when we take into consideration its high organic matter content and concentrations of plant nutrients. In this study, OMWs treated with two different methods were applied to a sandy loam texture soil at the rates of 0, 50, 100, 150 m3 ha-1. The experiment was carried out in total period of 90 days of incubation under laboratory conditions. C and N-dynamics analyses were performed in the soil samples which were taken from the pots at 30th, 60th and 90th days of incubation. Although OMW treatments did not have any significant effect to the amounts of Cçöz ve Chum, soil CO2 production was increased significantly. Applications of OMW immobilized the soil nitrogen in the first two months but later found out an increase of inorganic nitrogen forms in the soil with the increase of N-mineralization. Both raw and treated OMW applications can be recommended as a source of C, N, P and K to the soils because they did not cause any significant effect to soil C and N-dynamics and chemical properties of soil.