Soil inorganic carbon storage pattern in China

Abstract

Soils with pedogenic carbonate cover about 30% (3.44 Â 10 6 km 2 ) of China, mainly across its arid and semiarid regions in the Northwest. Based on the second national soil survey (1979)(1980)(1981)(1982)(1983)(1984)(1985)(1986)(1987)(1988)(1989)(1990)(1991)(1992), total soil inorganic carbon (SIC) storage in China was estimated to be 53.3 AE 6.3 PgC (1 Pg 5 10 15 g) to the depth investigated to 2 m. Soil inorganic carbon storages were 4.6, 10.6, 11.1, and 20.8 Pg for the depth ranges of 0-0.1, 0.1-0.3, 0.3-0.5, and 0.5-1 m, respectively. Stocks for 0.1, 0.3, 0.5, and 1 m of depth accounted for 8.7%, 28.7%, 49.6%, and 88.9% of total SIC, respectively. In contrast with soil organic carbon (SOC) storage, which is highest under 500-800 mm yr À1 of mean precipitation, SIC storage peaks where mean precipitation is o400 mm yr À1 . The amount and vertical distribution of SIC was related to climate and land cover type. Content of SIC in each incremental horizon was positively related with mean annual temperature and negatively related with mean annual precipitation, with the magnitude of SIC content across land cover types showing the following order: desert, grassland 4shrubland, cropland 4marsh, forest, meadow. Densities of SIC increased generally with depth in all ecosystem types with the exception of deserts and marshes where it peaked in intermediate layers (0.1-0.3 m for first and 0.3-0.5 m for latter). Being an abundant component of soil carbon stocks in China, SIC dynamics and the process involved in its accumulation or loss from soils require a better understanding.

Organic and inorganic carbon in the topsoil of the Mongolian and Tibetan grasslands: pattern, control and implications

“…Yang et al (2010a) estimated the SIC stock of the Tibetan grasslands to 15.2 Pg. Temperature and precipitation both show significant relationships with SIC density (Li et al, 2007;Mi et al, 2008;Yang et al, 2010a).…”

“…On the scale of the whole of China, SOC densities are significantly influenced by temperature (Xie et al, 2007), while soil moisture and texture control SOC density in the Tibetan grasslands (Yang et al, 2008;Baumann et al, 2009). For SIC, total stocks of the top 1 m are estimated to vary from 53.3 Pg to 77.9 Pg Mi et al, 2008;Li et al, 2007) in China. Yang et al (2010a) estimated the SIC stock of the Tibetan grasslands to 15.2 Pg.…”

“…Ni, 2002;Yang et al, 2010b;Wu et al, 2003;Yu et al, 2007;Xie et al, 2007;Baumann et al, 2009) as well as SIC (e.g. Yang et al, 2010a;Mi et al, 2008;Feng et al, 2002) in Chinese grasslands. SOC stocks are reported to range from 37.7 Pg (Xie et al, 2007) to 41.0 Pg (Ni, 2002) in Chinese grasslands, and about 16.7 Pg in northern China's grasslands (Yang et al, 2010b).…”

Comparing soil carbon loss through respiration and leaching under extreme precipitation events in arid and semi-arid grasslands

“…The SOC and N contents decreased with depth in all soils due to declining plant inputs (p < 0.05; Table 1), while the SOC:N ratio remained relatively similar (except a small decrease with depth in XLHT). By contrast, XLHT and GC soils showed an increasing SIC content with depth (p < 0.05; Table 1), because SIC, with a good solubility, is prone to leaching from the 25 topsoil and subsequently gets deposited in the deeper soil via salt formation (Mi et al, 2008;Tan et al, 2014). The KQ soil, showing an almost neutral pH, had an invariant SIC content and pH with depths.…”

Soil inorganic carbon stock in alpine grasslands on the Tibetan Plateau: an updated evaluation using deep cores

“…土壤无机碳在陆地碳循环中的作用不容忽视 (Mikhailova & Post, 2006;Georg et al, 2008;Stone, 2008;许乃政等, 2009;Zhang et al, 2015)。 尤其在干 旱和半干旱地区, 土壤无机碳库比有机碳库大2-10 倍 (Schlesinger, 1982;Somebroek, 1993;杨黎芳等, 2006; 余健等, 2014)，可能在区域碳循环中扮演着 重要角色。一方面, 成土风化过程中次生碳酸盐的 形成可以固定大气或土壤中分解产生的CO 2 (Lal, 2004;Mi et al, 2008;Tan et al, 2014), 且生成的碳 酸盐较为稳定 (Landi et al, 2003)。 因此, 土壤无机碳 在减少大气CO 2 浓度方面的贡献不容忽视 (Jacobson et al, 2002;Lerman & Mackenzie, 2005;Liu et al, 2010Liu et al, , 2011郑聚锋等, 2011)。另一方面, 工业革命 以来, 持续的大气氮沉降和农业活动引起的土壤酸 化导致了土壤中的大量碳酸盐以CO 2 的形式释放到 大气中 (Yang et al, 2010;Tan et al, 2014) (Post et al, 1982;Yang et al, 2007Yang et al, , 2009Zhang et al, 2010;Deng et al, 2014) 图2 青藏高原高寒草地不同深度土壤无机碳密度(SICD)的空间分布(分辨率为10 km × 10 km)。 …”