Effect of Treated Urban Sewage Sludge on Soil Essential Nutrients, Soil Chemical Properties and Physiological Properties of Olive Tree

Release of urban sewage in the environment is considered a serious problem to the environment and human health while its use in agriculture is recommended as a rich fertilizer in organic matter and major nutrients affecting plant growth. In this study، the use of treated urban sewage sludge، as a cheap organic fertilizer، a reproducible source in the nature and a municipal waste on the chemical properties of soil and essential nutrients of olive plant and soil alone and in combination with chemical fertilizer، was investigated. This study was conducted at Shahid Chamran University of Ahvaz greenhouse with 12 treatments and 3 replications within six months. Effects of sewage sludge، chemical fertilizer and combined effects on various parameters such as ECe، pH، organic matter content and essential nutrients of olive plant and soil and olive physiological characteristics were determined. Soil nutrient concentrations and physiological function of olive plants subjected to sewage sludge increased، and soil pH significantly decreased. The effect of sewage sludge and fertilizer on the vegetative components of the olive plant، including number of lateral branches، number of new leaves، height and leaf dry weight، significantly increased. Sewage sludge improved some soil chemical properties. 150 tons of sewage sludge per hectare without fertilizer treatment had the best effect on the properties of olive plants and soil. Sewage sludge increased the number of leaf، leaf area and organic matter content about twice times comparing with blank treatment but decreased 0. 4 unit pH. Effect of sewage sludge on soil potassium content was fewer than P and N.