Soil respiration dynamics in a semi-fixed sand dune under the pioneer shrub Artemisia halodendron Turcz. ex Bess. in the Horqin sandy land, northeastern China

Abstract

Soil respiration is a major pathway by which carbon dioxide (CO₂) fixed by terrestrial plants returns to the atmosphere. Studies of the dynamics of soil respiration in sandy land are rare and the contribution (R_c) of plant root respiration to the total soil respiration (R_t) is not well known. In this study, R_t in a semi-fixed dune planted with Artemisia halodendron was separated into autotrophic (root) respiration (R_a) and heterotrophic respiration (R_h) by the root-exclusion method. R_t and its two components were measured or calculated during 2013 on seven dates during the growing season when variation during the day was measured. Both R_a and R_h showed similar dynamics, with the maximum rates observed in July and with large daily variability observed on the earlier dates. R_c ranged from 39.3% to 53.1% during the growing season and exhibited a single peak in early August. Soil temperature at a depth of 20 cm was significantly correlated with soil respiration. R_a was more sensitive to soil temperature than R_h and the temperature sensitivity coefficients (Q₁₀) were 3.39, 2.52, and 2.79 for R_a, R_h, and R_t, respectively. In summary, A. halodendron roots contributed an average of 46% to the total soil respiration, although this contribution varied during the growing season.

Keywords:

• Artemisia halodendron
• Horqin sandy land
• root contribution
• root respiration
• seasonal variation
• total soil respiration

Acknowledgments

We thank our colleagues at the Naiman Desertification and Farmland Research Station, Chinese Academy of Sciences, for their help with the field investigation.

Additional information

Funding

This work was financially supported by the National Key Research and Development Plan of China [2017YFA0604803, 2016YFC0500907], the National Natural Science Foundation of China [No. 31500369], the science and technology major project of Inner Mongolia Autonomous Region “platform construction of big data on grass ecology and research of application and development”, and the Foundation for Excellent Youth Scholars of Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences [Y651K21001].