Effect of Sewage Sludge on Microbial Activity in an Old, Abandoned Minesoil

Abstract

Abstract The effect of lime, fertilizer, and sewage sludge (50 and 100 kg ha −1 ) upon microbial activity and growth of sparsely distributed tall fescue ( Festuca arundinaceae Schreb.) on an old, acidic, infertile sandy loam (Typic Udispolents; loamy‐skeletal, mixed, acid, mesic) minesoil was evaluated. Respiration rate and activities of amylase, urease, and phosphatase were used as indices of microbial activity. When compared with the control, lime significantly increased respiration rate, had no affect upon amylase and urease activities, and significantly reduced phosphatase activity. Fertilizer significantly increased respiration rate and amylase activity, but significantly decreased urease activity. Phosphatase activity was not affected by fertilizer applications. Lime plus fertilizer significantly increased respiration rate and amylase activity, had no affect upon phosphatase activity, while it drastically reduced urease activity. Sludge at both rates of application in conjunction with lime and fertilizer (S 1 LF, S 2 LF) are only compared with the lime‐fertilizer treatment. Both S 1 LF and S 2 LF significantly increased respiration rate and urease activity; S 2 LF was significantly more effective than S1LF. Amylase activity was significantly increased by both S 1 LF and S 2 LF, although there was no difference between the two treatments. The S 1 LF had no affect upon phosphatase activity, whereas S 2 LF caused a significant activity increase. All treatments produced significant increases in tall fescue yield. Fertilizer was significantly more effective than lime. The fertilizer and the lime‐fertilizer treatments were about equally effective. Both S 1 LF and S 2 LF produced yields that were significantly greater than the lime‐fertilizer treatment. The S 2 LF had a significantly greater effect upon yield than did S 1 LF.