Effect of Warming on Dissolved Organic Matter in Litter of Subtropical Evergreen Broad-leaved Forest

Abstract:

In order to understand the effect of warming on litter decomposition, the litter collected in subtropical evergreen broad-leaved forest was distributed in control and warming (+4 ℃) plots, respectively. The changes in the quantity and spectral characteristics of dissolved organic matter during litter decomposition under warming were studied. The results showed that the mass residual rate of litter decreased significantly with decomposition process, rapidly decreased by 20.08% to 23.32% in 0-60 days, and slowly decreased by 6.35% to 10.98% in 60-210 days. Along decomposition process, the dissolved organic carbon content of litter source showed a decreasing trend of first fast and then slow, and the overall decrease was 94.15%. The content of dissolved organic nitrogen fluctuating decreased by 81.82% overall. The spectral characteristics of dissolved organic matter (SUVA₂₅₄, SUVA₂₆₀, SUVA₂₈₀ and SUVA₃₇₀) showed an increase-decrease-increase tendency. The warming did not significantly affect the mass residual rate of litter and the spectral characteristics of dissolved organic matter, but the contents of dissolved organic carbon and organic nitrogen decreased by 16.72% and 25.10%. Therefore, the decomposition of litters decreased the mass residual rate of litters and the contents of dissolved organic carbon and organic nitrogen, and changed the spectral characteristics of dissolved organic matter. Although warming decreased the contents of dissolved organic carbon and organic nitrogen in litters, it did not significantly change the mass residual rate and spectral characteristics of dissolved organic matter in litters.