Soil oxidases recovered faster than hydrolases in a 50-year chronosequence of desert revegetation
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Aims: Desert characterized by alkaline soil with low organic matter and nutrients has a high soil oxidative potential. We hypothesized that oxidase activities would recover faster than hydrolases during the succession of sand-fixing community. Methods: Sand dunes stabilized in different years, including a moving sand dune and a steppe at the southeastern fringe of the Tengger Desert, were selected to investigate restoration of extracellular enzyme activities (EEAs) in a 50-year chronosequence. Results: Oxidases showed significantly higher activities than hydrolases at all ten studied sites and EEAs exibited a decreasing trend from catalase, phenol oxidase, sucrase, urease, alkaline phosphatase, -Amylase to cellulase. After 50 years of revegetation, most EEAs in topsoil recovered to 50-83% of that of the steppe except for urease. Oxidase activities recovered earlier and faster than hydrolases, while hydrolases activities attained the fastest recovery at 19-25 years in the 50-year chronosequence. Conclusions: Recovery of EEAs was modulated by the succession of the sand-fixed community: oxidases activities exhibited peak recovery rates at the stage when shrubs dominated the community, while recovery of hydrolases activities appeared to be mainly regulated by biological soil crusts and annual plants. 2012 Springer Science+Business Media B.V.