Soil warming decreased dissolved organic carbon quantity and quality in subtropical forests.

doi:10.13287/j.1001-9332.202303.017

Abstract

Abstract: Soil dissolved organic carbon (DOC) is the most active part in forest soil carbon pool, the responses of which to climate warming has profound effects on forest carbon cycling. Based on a manipulative soil warming experiment in subtropical evergreen broad-leaved forests, we collected soil solutions in situ and used ultraviolet-visible, infrared and three-dimensional fluorescence spectroscopy analyses to explore the effects of soil warming (+4 ℃, 1 year) on soil DOC quantity and quality along the soil profile. The results showed that soil DOC flux remained constant along the soil profile. Soil DOC mainly included two humic-like fractions and one microbial metabolite. Warming significantly decreased soil DOC flux and the abundance of aromatic and hydrophobic components, and increased the amount of low molecular weight carbohydrates. Furthermore, soil warming increased the relative proportion of humic-like fractions in the surface soil layer (0-10 cm) and microbial metabolite in the deep soil layer (30-40 cm), indicating that warming might accelerate microbial turnover in the deep layer. Overall, soil warming not only decreased soil DOC content, but also simplified the composition of soil DOC in subtropical evergreen broad-leaved forests.

Key words: soil warming, subtropical forest, dissolved organic carbon, ultraviolet-visible spectroscopy, infrared spectroscopy, three-dimensional fluorescence spectroscopy

MAO Chao, LIN Weisheng, XU Chao, LIU Xiaofei, XIONG Decheng, YANG Zhijie, CHEN Shidong. Soil warming decreased dissolved organic carbon quantity and quality in subtropical forests.[J]. Chinese Journal of Applied Ecology, 2023, 34(3): 623-630.

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