Journal of Environmental Biology

Studies on the variation of CO₂ fluxes and its characterization with soil temperature, moisture and dissolved organic carbon under different sulfur levels from alpine grassland in the Tibetan Plateau

X. Zeng¹ and Y. Gao²*

¹Department of Landscape Architecture, Sichuan College of Architectural Technology,  Chengdu-610399, China

²Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu-610041, China

*Corresponding Author E-mail: yhgao@imde.ac.cn

Key words

CO₂ fluxes,

Dissolved organic carbon

Microbial activity

Soil temperature,

Sulfur deposition

Publication Data

Paper received : 29.08.2016

Revised received : 26.12.2016

Accepted : 23.01.2017

Abstract

Aim: The effect of sulfur deposition on the carbon dynamics of alpine grasslands has received little attention The present study was carried out to determine the influence of sulfur addition on temporal variation of CO₂ fluxes and characterize the relationships between CO₂ fluxes and soil temperature, moisture and dissolved organic carbon from alpine grassland in the Tibetan Plateau.

Methodology: Based on a multi-level S (0, 2 and 6 g S m^-2 yr^-1) addition experiment, soil CO₂ fluxes were monitored by static chamber and gas chromatograph technique within Tibetan alpine grassland during the growing seasons in 2013 and 2014. Soil temperature, moisture, dissolved organic carbon, microbial carbon and nitrogen and enzyme activities were measured to examine the key driving factors of soil CO₂  fluxes. 

Results: No significant differences in CO₂ fluxes between treatments were observed during almost all the sampling periods, but sulfur deposition increased mean soil dissolved organic carbon concentrations. Sulfur deposition tended to inhibit soil microbial carbon and nitrogen and enzyme activities.Regardless of sulfur treatment, soil temperature was the primary control on seasonal variation of CO₂ fluxes in both 2013 and 2014, but these fluxes were not limited by soil moisture in 2013.     

Interpretation: The result indicated that CO₂ fluxes from Tibetan alpine grasslands resulted from mineralization of soil dissolved organic carbon and the potential increasing atmospheric sulfur deposition could have limited effects on CO₂ emission from the alpine grasslands.

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