Effects of Elevated CO2 on Accumulation of Soil Neutral Sugars in a Rice-wheat Rotation Field

Experimental platform of free-air CO2 enrichment (FACE) was established in mid June of 2004 over a rice-wheat rotation ecosystem located at a suburb of Jiangdu, China. We compared the dynamics of soil neutral sugars from a wheat field with high (225.0 kg N/hm2) and low (112.5 kg N/hm2) levels of N fertilization exposed to the elevated and ambient CO2 after the wheat growing season in 2008. The results showed that soil glucose sugar accounted for the majority of total neutral sugars irrespective of elevated CO2 and N fertilization. Compared with the ambient treatments, elevated CO2 increased the amount of soil neutral sugars irrespectively of low N fertilization and high N fertilization, however, the difference was not significant. The ratios of (G+M)/(A+X) indicated that the origin of soil neutral sugars came from both plants and microbes. The elevated CO2 and N fertilization had no effects on the ratio of (G+M)/(A+X) (P >; 0.05).