Carbon Storage and Vertical Distribution in Three Shrubland Communities in Gurbantünggüt Desert

Arid and semi-arid regions, covering 47% of lands in the world, contain approximately 10% of the global soil organic carbon (SOC), which plays a significant role in global carbon cycling. Previous studies showed that soil carbon storage was significantly correlated with the soil depth and soil properties. However, most of these studies paid their attention to the upper layer of soil carbon pool (1–3 m in depth), while carbon storage in the deeper soil layers was neglected.

The Gurbantünggüt Desert is the second largest desert of China, with a covering area of 4.88 × 10⁴ km². The results of many studies showed that the arid shrubland communities in this area are a large carbon sink for global carbon cycle. However, the content, contribution and vertical distribution of different carbon pools in Gurbantünggüt Desert are still unknown.

To quantify the storage of plant biomass carbon and SOC, distinguish their relative contribution to the total carbon pool and analyze their vertical distribution in shrubland communities of Gurbantünggüt Desert, Prof. HU Yukun and his research team investigated the carbon concentrations and its vertical distribution in three different desert shrubland communities which dominated by Reaumuria soongorica, Haloxylon ammodendron + R. soongorica and Tamarix ramosissima + R. soongoric, repectively. In addition, the relationships between SOC and soil total nitrogen were examined.

The results showed that SOC was considerably the larger carbon pool in the soil layers of 1.0–3.0 m (the mean value of three shrub-land communities was 38.46%) and 3.0–5.0 m (the mean value was 40.24%). In contrast, 70.74% of belowground biomass carbon storage in 0–1.0 m layer, and its content decreased with increasing soil depth. The H. ammodendron + R. soongorica shrubland community had the highest belowground biomass carbon among three selected communities. The study highlights the importance of SOC stored in deep soil layers (lower than 3.0 m from the surface) in arid shrubland communities in the global carbon balance. In addition, it provides the data support for revealing deep soil solid carbon potential, and offers scientific basis for the further research in the carbon cycle of terrestrial ecosystem.

The result has been published on Chinese Geographical Science, 2012, 22(5): 541-549. The paper can be downloaded from http://www.springerlink.com/content/dw562827q427um85/.