PS 46-131 - Changes in terrestrial productivity and soil carbon storage induced by climate variability and land use in China’s Loess Plateau during 1950-2008

Wednesday, August 10, 2011
Exhibit Hall 3, Austin Convention Center
Yaai Dang1, Wei Ren2, Bo Tao2, Chaoqun Lu2 and Hanqin Tian2, (1)School of Forestry and Wildlife Sciences, Auburn University,Northwest Agriculture and Forestry University, (2)International Center for Climate and Global Change Research and School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL

The Loess Plateau in China, a climate-sensitive zone and a fragile ecological environment belt, has been suffering from extraordinary serious soil loss caused by natural and anthropogenic disturbances (e.g. climate change, land conversion etc.) in the past decades. Evidence shows that the tendency of warming and drying in climate has significantly led to much enhanced soil erosion in such area. To reduce soil erosion and improve land quality, China initiated the state-funded project "Grain-for-Green" in the Losses Plateau since 1999. However, limited attention has been paid to the effect of land use conversion on soil carbon storage in the region after implementing the project. Therefore, this study aims to investigate the temporal and spatial patterns of terrestrial productivity and soil carbon storage induced by changes in climate and land use/land cover, by integrating field experiments and observations with a process-based ecosystem model (the Dynamic Land Ecosystem Model-DLEM) driven by refined regional and gridded database and site observation data.


The preliminary results at regional level show that climate change controlled the interannual patterns of terrestrial productivity(NPP) and reduced soil carbon storage (SOC); land conversion from natural ecosystem to cropland contributed to some extent increase in crop production but decrease in SOC during 1950-1999. Nevertheless, both model results and observations at site level (collected in several long-term experimental sites across Loess Plateau since 1999) indicated that SOC significantly increased after adopting fallow practices and the long-term fallow (e.g. 20-year fallow vs. 5-year fallow). Our results also suggest that the conversion of farm land system into forest or grassland ecosystems were favorable for the accumulation of soil organic carbon.

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