Study of Soil Organic Carbon Structural Change of Fallowing Grasslands by Synchrotron Radiation Spectrum Technology
LI Ting1, 2, ZHAO Shi-wei1, 3*, MA Shuai1, 2, LI Xiao-xiao1, 2
1. State Key Lab of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, China 2. Graduate University of Chinese Academy of Sciences, Beijing 100049, China 3. Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, China
Abstract：Synchrotron radiation soft X-ray and SR-FTIR spectroscopy technique were used to study the change of soil organic carbon(SOC) structure in ＜0.25 mm aggregate soil from fallowing grasslands of Yun-wu mountains. Results obtained by SR-FTIR technique were qualitatively analyzed, which indicated that compared with slope farmland, the peak intensity of aliphatic-C from fallowing grasslands significantly increased, while peaks intensity of aromatic-C, alcohols-C, carboxyl-C, polysaccharide-C didn’t significantly change with increasing years of fallowing. Results obtained by SR-FTIR technique were semiquantitatively analyzed, which showed that compared with slope farmland, the relative content of functional groups from fallowing grasslands SOC was increased, the growing rate of aliphatic-C, alcohols-C in 0～5 cm and 10～20 cm soil horizon was greater than growing rate of aromatic-C. Results obtained by soft X-ray technique are consistent with SR-FTIR, and the relative content of the same functional groups (aliphatic-C, aromatic-C) gained by two determination methods were T-tested, which was not significant (P>0.05), indicating that using synchrotron radiation soft X-ray for the determination of SOC structural change of fallowing grasslands is feasible.
Key words：Functional groups of organic carbon;Fallowing grasslands;XANES;SR-FTIR
