Effects of Recent Forest Clearcut on Particulate Organic Matter

Effects of Recent Forest Clearcut on Particulate Organic Matter, Abdelrahman, Hamada, WIEKENKAMP Inge, BERNS Anne E., UNGER Kirsten, LEHNDORFF Eva, HOFMANN Diana, KUZYAKOV Yakov, and BOl Roland , The 18th International Conference of the International Humic Substances Society, Kanazawa, Japan, (2016)

It is important to take measurements shortly after a forest trees clearcut in order to understand its environmental effects and to determine the possible counter measures to limit the impact. Soil samples were therefore collected from a forest site before and after the clearcut, i.e. 2013 and 2014, respectively, in order to understand the changes in soil C from different fractions. Six profiles from the Eifel National Park, Germany, were sampled for the surface bulk soil, Oh and Ah horizon. Samples were fractionated and each fraction was characterized for its mass, C, N, δ 13C and δ 15N with selected 13C CPMAS NMR measurements Results did show a clear decrease in the fractional masses of the four separated fractions after the clearcut which might be related to the decomposition of the organic matter that binds/cements soil aggregates. In the Oh horizon, there was a slight decrease in the total spectral area that was assigned to different functional groups. The changes in the δ 13C signature after one year may point to slight depletion of the 13C. The δ 15N signature ranged from -0.4 – +3.5‰, showing especially a relative enrichment of 15N in the 096 profile. Our work points toward a measurable impact of the clearcut on the soil C and N stores and dynamics following the clearcut.

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