Microtopographic variation in soil respiration and its controlling factors vary with plant phenophases in a desert–shrub ecosystem
Soil respiration (<i>R</i><sub>s</sub>) 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 <i>R</i><sub>s</sub> and...
| Main Authors: | , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-10-01
|
| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/12/5705/2015/bg-12-5705-2015.pdf |
| Summary: | Soil respiration (<i>R</i><sub>s</sub>) 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
<i>R</i><sub>s</sub> and to understand the plant effects on the spatial variation
in <i>R</i><sub>s</sub> 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 (<i>Artemisia ordosica</i>).
Coefficient of variation (i.e., standard deviation/mean) of <i>R</i><sub>s</sub>
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 <i>R</i><sub>s</sub>. During the flower-bearing phase, root biomass affected
<i>R</i><sub>s</sub> most, explaining 72 % of the total variation. During the
leaf coloration–defoliation phase, soil nitrogen content affected
<i>R</i><sub>s</sub> the most, explaining 56 % of the total variation. Our
findings highlight that spatial pattern in <i>R</i><sub>s</sub> was dependent on
plant distribution over a desert sand dune, and plant-related factors largely
regulated topographic variation in <i>R</i><sub>s</sub>, and such regulations
varied with plant phenology. |
|---|---|
| ISSN: | 1726-4170 1726-4189 |