Articles | Volume 12, issue 19
Biogeosciences, 12, 5705–5714, 2015
Biogeosciences, 12, 5705–5714, 2015

Research article 08 Oct 2015

Research article | 08 Oct 2015

Microtopographic variation in soil respiration and its controlling factors vary with plant phenophases in a desert–shrub ecosystem

B. Wang1,2, T. S. Zha1, X. Jia1,2, J. N. Gong2, B. Wu1, C. P. A. Bourque3, Y. Zhang1, S. G. Qin1, G. P. Chen4, and H. Peltola2 B. Wang et al.
  • 1Key Laboratory of Soil and Water Conservation and Desertification Combating, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
  • 2School of Forest Sciences, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, Finland
  • 3Faculty of Forestry and Environmental Management, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada
  • 4Institute of Forestry Sciences, Bailongjiang Forestry Management Bureau of Gansu Province, 746010, China

Abstract. Soil respiration (Rs) and its biophysical controls were measured over a fixed sand dune in a desert–shrub ecosystem in northwest China in 2012 to explore the mechanisms controlling the spatial heterogeneity in Rs and to understand the plant effects on the spatial variation in Rs in different phenophases. The measurements were carried out on four slope orientations (i.e., windward, leeward, north- and south-facing) and three height positions on each slope (i.e., lower, upper, and top) across the phenophases of the dominant shrub species (Artemisia ordosica). Coefficient of variation (i.e., standard deviation/mean) of Rs across the 11 microsites over our measurement period was 23.5 %. Soil respiration was highest on the leeward slope, and lowest on the windward slope. Over the measurement period, plant-related factors, rather than microhydrometeorological factors, affected the microtopographic variation in Rs. During the flower-bearing phase, root biomass affected Rs most, explaining 72 % of the total variation. During the leaf coloration–defoliation phase, soil nitrogen content affected Rs the most, explaining 56 % of the total variation. Our findings highlight that spatial pattern in Rs was dependent on plant distribution over a desert sand dune, and plant-related factors largely regulated topographic variation in Rs, and such regulations varied with plant phenology.

Final-revised paper