The Effects of Sewage Sludge on Some Physical and Chemical Properties of Soil and Wheat Yield

Sewage sludge is an important source of organic matter, nitrogen, phosphorus and other nutrients. This sludge can be used as an organic fertilizer to improve the soil and it’s fertility by a correct management. In present study an investigation was carried out in order to checking the effects of sewage sludge on yield of two types of wheat species (Sivand and Roshan) and some physical and chemical properties of the soil.The investigation was done in the form of a factorial experiment as a completely randomized design with three replications and three levels of sludge(zero, 60 and120 g kg-1soil) in research greenhouse of the Yazd University. The results showed that application of sewage sludge comparing control treatment caused a significant increase in the leaf surface, dry weight of aerial parts, seed number and total seed weight in the Sivand and Roshanas the two studied varieties, although the Roshan wheat height in control treatment was more than that is sewage sludge treatments. With increasing the level of sewage sludge, soil electrical conductivity increased too.While, soil pH and soil bulk dencity at treatment with 60 and 120g kg-1 of sludge showed a significant decrease as compared to the control treatment. Furthermore, the treatments of sewage sludge in comparison with control treatment increased the organic carbon, total nitrogen, phosphorus and absorbable potassium of the soil. According to the results, sewage sludge could increase soil fertility and plant yield by improving some physical and chemical properties of the soil.