Enzyme Activity and Respiration in Minesoils

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Abstract
Microbial respiration and soil enzyme activity measurements were made in both native soils and in minesoils varying in age and vegetation in order to determine the levels of microbial activity during the initial stages of soil genesis. By all indices, microbial activity was lower on unfertilized minesoils than in native soils. Amylase and phosphatase activities increased with time, as did respiration rate, so that after 20 years, activity levels in the surface 10 cm approached those of native soils. Recovery was related to the accumulation of organic matter and nitrogen (N). Recent minesoils receiving high inputs of lime and fertilizers had the highest activity levels found, resulting in a depletion of organic matter and nitrogen which suggests that a self‐sustaining ecosystem has not yet developed on these sites.Respiration rate, and amylase and phosphatase activities were all significantly correlated with each other. Oxidizable carbon (C) and total and mineralizable nitrogen were the soil factors most closely correlated with respiration rate, while clay content also affected amylase activity. Urease activity was not correlated with any of the other indices or soil factors studied.No evidence for enzyme inhibition in minesoils was found, but phosphatase activities were lower in minesoils, suggesting that P mineralization may be slower on minesoils. Mineralizable N increased rapidly with age on unamended sites, but after 20 years it was only one‐half that found in native soils.The presence of vegetation was critical for the recovery of microbial activity. Black locust (Robinia pseudoacacia) was similar to grasslegume vegetation in its effect on microbial activity and N accumulation. Compaction of the soil during reclamation caused slow organic matter and N accumulation, and thus low microbial activity.
Funding Information
  • WVU Mining and Mineral Research Inst. (MI 8050R)