β-Glucosidase activity in soils amended with sewage sludge

• Published in: Agriculture, ecosystems & environment ecosystems & environment, 1993-01, Vol.43 (2), p.155-161
• Main Authors: Eivazi, F., Zakaria, A.
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Other nutrients. Amendments. Solid and liquid wastes. Sludges and slurries; Soil-plant relationships. Soil fertility. Fertilization. Amendments
• ISSN: 0167-8809; 1873-2305
• DOI: 10.1016/0167-8809(93)90117-8

In a laboratory experiment three soil types were treated with two sources of sewage sludge at four rates. β-Glucosidase activity was assayed after 0, 7, 14, and 30 days of incubation. At the lower loading rates (10 and 30 mg sludge g −1 soil) β-glucosidase activity was inhibited but enhanced activity was observed at higher application rates (100 and 200 mg sludge g −1 soil). Inhibition of enzyme was more pronounced with St. Louis sludge (66%) at 30 days of incubation and is attributed to the higher concentration of trace metals in this sludge source. The enhanced activity of β-glucosidase ranged from 1.2 to 4-fold (Elk soil), 1.21 to 3.67-fold (Lilbourn soil), and 1.13 to 3.28-fold (Waldron soil). This increase in enzyme activity was attributed to the enhanced microbial activity which was stimulated with higher nutrients and organic matter cottent of sludge-amended soils. Furthermore, binding with humic substances and clay minerals may have played a role in reducing the adverse effects of heavy metals. However, potential hazards associated with land application of sewage sludge such as NO 3 − leaching into the ground water, accumulation and addition of heavy metals in the soils, germination and plant growth inhibition, remain to be a serious ecological problem.