Abstract
Increasing nitrogen (N) deposition has been reported to result in positive, negative, and neutral impacts on soil oxidative enzyme activities, which are associated with lignin degradation. The oxidative enzyme activities are usually high and stable in desert ecosystems. Therefore, the exploration of how these enzymes respond to N addition is critical to evaluate the carbon transformation in desert ecosystems. We present the seasonal variations in oxidative enzyme activity and their responses to simulated N deposition in the topsoil (0–5cm) and in subsoil (5–10cm) of the Gurbantunggut Desert in Northwestern China. Polyphenol oxidase (PPO) and peroxidase activity exhibited clear seasonal variations over the 2-year study, with relatively higher values in spring than in the other seasons. The seasonal changes in oxidative enzyme activity were mainly driven by the seasonal patterns in soil moisture and temperature. Shifts in pH, organic carbon, and electrical conductivity were not closely correlated with the seasonal changes in oxidative enzyme activity. In general, PPO and peroxidase activity responded minimally to low N addition (0.5–3gNm−2yr−1), but the activity decreased in response to high N addition (6–24gNm−2yr−1). Although higher organic carbon concentrations were observed in the topsoil than in the subsoil, few significant differences in PPO and peroxidase activity and in their sensitivity to N addition were observed between the two layers. These results suggest that the carbon transformation related to oxidative enzyme activity is regulated by the seasonal patterns of soil moisture, soil temperature, and the N concentration in desert soil.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.