Application of Sewage Sludge as a Soil Physical and Chemical Amendment

The effect of sewage sludge application on some soil physical and chemical properties was studied between years 2004 and 2007 in Igdir plain (Aralik), Turkey. The experiments were conducted using a complete randomized block design with three replications in 12 plots, each measuring 3.0 m x 3.0 m (9 m(2)). Anaerobic digested sewage sludge, obtained from wastewater treatment plant of Municipality of Ankara, was mixed to the arable layer (0 - 25 cm) of the experimental site in July 2004 in the rates of 0 (Control), 4, 8 and 12 t da(-1) dry weight of sewage sludge, no sewage sludge application was made after this date. Application of sewage sludge to saline-sodic soil enhanced not only soil physical properties but also chemical properties. However, this effect has changed with years and application rates. Considering the physical and chemical properties, the most effective application ratio was found as 12 t da(-1). But these positive effects were not reached to desired levels in soil exchangeable sodium percentage (ESP). Therefore, application of sewage sludge to saline-sodic soils should be done after reclamation. Results obtained have showed that sewage sludge is an alternative way to improve soil physical and chemical properties and productivity, as well as to protect environmental pollution.