Sequestration of microbial, aged and pyrogenic N during paddy soil development
Zusammenfassung der Projektergebnisse
Within this research unit we learned about the cycling of organic matter in soil, in P3 especially about cycling of N and black carbon. The chronosequence of paddy and non-paddy soils showed the influence of soil formation on N and BC accumulation under different soil management conditions. Indeed, frequent flooding in paddy soils let to an enhanced accumulation of N and BC, which filled the stocks of these soils within about 300 years. In non-paddy, upland crop soils N and BC stocks were filled much earlier, i.e. within 100 years. This let us to assume that generally flooding leads to a decreased turnover of organic matter and this was the starting point for the second phase of this research unit. Another finding form the first phase seemed to be generalizable to all kinds of paddy managed soil and this was the very limited transfer of matter from the top- to the subsoil. This was related to the dense plough pan, which typically establish during puddling of paddy soil. However, artificial labeling experiments in a greenhouse led to the assumption that C and N cycling in the short-term does not differ significantly between young and old paddy soil (with a typical hydragic pedon). The second phase was designed to test the hypothesis that flooded, paddy soils accumulate more N, black N and BC, and that this is limited to the topsoil. Indeed we found highly different N and BC stocks, but surprisingly this did not depend on soil management but almost exclusively on the major soil properties, especially on clay and oxide contents. The abundance of aromatic N forms was low and could not be related to BC indicating that other processes lead to aromatic N formation in soil than input of charred organic matter. The decoupling of top- and subsoil via puddling, as observed in the young paddy soils of the Chinese chronosequence, did not appear in mature soils. It seems likely that in young soils (first 100 to 300 years of the chronosequence was soil which formed newly on marsh land) management has a much higher effect on organic matter dynamics than in mature soils (all soils older than 300 years).
Projektbezogene Publikationen (Auswahl)
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2010. Biogeochemistry of paddy soils. Geoderma 157: 1-14
Kögel-Knabner I., Amelung W., Cao Z., Fiedler S., Frenzel P., Jahn R., Kalbitz K., Kölbl A., Schloter M
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2011. Accumulation of nitrogen and microbial residues during 2000 years of rice paddy and non-paddy soil development in the Yangtze River Delta, China. Global Change Biology 17, 3405-3417
Roth, P.J., Lehndorff, E., Cao, Z.H., Zhuang, S., Bannert, A., Wissing, L., Schloter, M., Kögel- Knabner, I., Amelung, W.
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2012. Intra-versus intersite macroscale variation in biogeochemical properties along a paddy soil chronosequence, Biogeosciences
Mueller-Niggemann, C., Bannert, A., Schloter, M., Lehndorff, E., Schwark, L.
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2013. Accelerated soil formation due to paddy management on marshlands (Zhejiang Province, China). Geoderma 228-229, 67–89
Kölbl, A., Schad, P., Jahn, R., Amelung, W., Bannert, A., Cao, Z., Fiedler, S., Kalbitz, K., Lehndorff, E., Müller-Niggemann, C., Schloter, M., Schwark, L., Vogelsang, V., Wissing,L., Kögel-Knabner, I.
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2013. Cycling of rice rhizodeposits through peptide-bound amino acid enantiomers in soils under 50 and 2000 years of paddy management. Soil Biology and Biogeochemistry 65, 227-235
Roth P.J., Lehndorff, E., Hahn. A., Frenzel, P., Amelung, W.
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2014. Black carbon accrual during 2000 years of paddy-rice and non-paddy cropping in the Yangtze River Delta, China. Global Change Biology, gcb.12468
Lehndorff, E., Roth, P.J., Cao, Z.H., Amelung, W.
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2016. Response of Vertisols, Andosols, and Alisols to paddy management. Geoderma 261, 23–35
Winkler, P., K. Kaiser, A. Kölbl, T. Kühn, P. Schad, L. Urbanski, S. Fiedler, E. Lehndorff, K. Kalbitz, S.R. Utami, Z. Cao, G. Zhang, R. Jahn, I. Kögel-Knabner
