نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشجوی کارشناسی ارشد و استادیار گروه خاکشناسی، دانشکده کشاورزی، دانشگاه صنعتی اصفهان و استادیار پژوهش موسسه تحقیقات آب و خاک
2 و استادیار گروه خاکشناسی، دانشکده کشاورزی، دانشگاه صنعتی اصفهان
3 استادیار پژوهش موسسه تحقیقات آب و خاک
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Increasing soil organic matter can improve plant growth due to its effects on physical, chemical and biological properties of soil. Transformation of essential elements from organic form under the influences of intra- and extra-cellular enzymes and other microbially mediated processes can increase plant growth. The aim of this study was to identify the effects of different rates and times of sewage sludge application on L-glutaminase, alkaline phosphatase, arylsulfatase and β-glucosidase activities, microbial biomass index and corn yield. Three levels of application (0, 25 and 100 Mg ha-1) and four consecutive times of sewage sludge application (1, 2, 3 and 4) were studied in a randomized complete block split plot design with three replications. Composite soil samples were collected from 0-15 cm depth at the end of 4th year of application. Results illustrated that application of sewage sludge increased soil organic carbon (SOC) and total nitrogen (TN) compared with control treatment. An increasing trend was observed in SOC and TN, as the rates and times of applications increased. Increasing the times and rates of application also enhanced L-glutaminase, alkaline phosphatase, arylsulfatase, β-glucosidase activities, microbial biomass index and corn yield, significantly. The lowest levels of enzyme activities and microbial biomass indices were observed in the control treatment. Four consecutive applications of 100 Mg ha-1 sewage sludge was associated with the highest levels of the bio-indicators. We concluded that functional biodiversity increased in soils that were amended with sewage sludge.
کلیدواژهها [English]