Monitoring the changes in the microbial dynamics of calcareous soil with the amendment of stabilized and dried sewage sludge in mediterranean region of turkey

Abstract

Since sewage sludge contains plant nutrients and organic matter, it has a potential to act as a soil conditioner for maintainig soil fertility in crop production. In this experiment, different quantities of stabilized and dried sewage sludge (SS) were applied to a calcareous soil. Treatments used for this study were 0 t ha-1 (SS0/control), 20 t ha-1 (SS2), 40 t ha-1 (SS4), 60 t ha-1 (SS6), 80 t ha-1 (SS8) respectively. This study was aimed to investigate the changes in soil microbial dynamics by application of sewage sludge during growing crop conditions. A field experiment was done by using randomized blocks design and every treatment was replicated four times. Soil samples were collected at three different periods of plant growth. Number of bacteria (heterotrophic aerobic mesophilic) and changes in soil enzyme activities (nitrification, nitrate reductase, urease, alkaline phosphatase, β-glycosidase) were examined. According to the results, it is clear that the sludge applications have stimulating effect both on soil enzyme activities (excluding nitrate reductase) and the number of bacteria. With the application of sewage sludge soil microbial dynamics significantly increased (nitrification = 41.72%, urease = 35.14%, alkaline phosphatase = 43.29%, β-glycosidase = 59.64%, number of bacteria = 91.66%) as compared to the control.