Coordination of the Research Unit and development of a conceptual model of paddy soil evolution

• Applicant: Professorin Dr. Ingrid Kögel-Knabner
• Subject Area: Soil Sciences
• Term: from 2008 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 55047603

• Final Report Year: 2016

Final Report Abstract

During the first phase, the aim of PZ was to investigate the development of the spatial heterogeneity of SOM (and related parameters) during paddy soil evolution. Therefore, PZ analysed the development of the spatial variability of SOM with increasing duration of paddy management in order to be able to distinguish between natural heterogeneities and variabilities caused by different duration of paddy soil use. A geostatistical sampling approach was used to estimate the order of magnitude in which processes can occur in representative areas. Against our expectation, we found moderate spatial dependencies for OC in both 50 and 300 years old paddy topsoils, thus neither increasing nor decreasing spatial heterogeneity with time of paddy soil use. In the younger topsoil, soil lightness turned out to be a good predictor for SOM distribution. In contrast, soil lightness was not a useful indicator for SOM distribution in the older paddy topsoil. The spatial pattern of SOM was only partly reflected by soil lightness. This was explained by an ongoing uneven incorporation of burnt straw residues which did not increase the total SOM content, but let to selective enrichment of dark aromatic SOM compounds. During the second phase, the aim of PZ was the development of a conceptual model of paddy soil evolution, with special regard to the following questions:  how far does paddy management influence and change main characteristics of different parent soil types?  how far this can be attributed to the parent soil type? We hypothesised that paddy soil development leads to different soil characteristics depending on the parent soil types. To check the hypotheses, a general linear model approach was used to evaluate the impact of the factor “soil type” and the factor “management” on basic topsoil parameters. With this approach, we were able to identify exclusively soil type – related parameters (e.g. Ca, Mg and CECpot), reflecting the underlying parent material. Mostly management-dependent parameters like Na and EC reflect possible salt inputs due to irrigation water. Fe oxides, but also OC and N concentrations are mainly soil type-dependent, but reflect additionally management effects. To conclude, easily soluble salts, crop residue-related SOM input, and redox-sensitive components like Fe-oxides are useful to distinguish between paddy and non-paddy management, while Ca, Mg and CECpot exclusively separate parent soil types.

Publications

• 2010. Biogeochemistry of paddy soils. Geoderma, 157: 1-14
  Kögel-Knabner, I., Amelung, W., Cao, Z.H., Fiedler, S., Frenzel, P., Jahn, R., Kalbitz, K., Kölbl, A., Schloter, M.
  
• 2011. Organic carbon accumulation in a 2000-year chronosequence of paddy soil evolution. Catena, 87: 376–385
  Wissing L., Kölbl A., Vogelsang V., Fu, J.-R., Cao Z.-H., Kögel-Knabner I.
  
• 2013. Management-induced organic carbon accumulation in paddy soils: The role of organo-mineral associations. Soil & Tillage Research, 126: 60-71
  Wissing, L., Kölbl, A., Häusler, W., Schad, P., Cao, Z.H., Kögel-Knabner, I.
  
• 2013. The carbon count of 2000 years of rice cultivation. Global Change Biology, 19: 1107–1113
  Kalbitz, K., Kaiser, K., Fiedler, S., Kölbl, A., Amelung, W., Bräuer, T., Cao, Z., Don, A., Grootes, P., Jahn, R., Schwark, L., Vogelsang, V., Wissing, L., Kögel-Knabner, I.
  
• 2014. Accelerated soil formation due to paddy management on marshlands (Zhejiang Province, China). Geoderma, 228: 67-89
  Kölbl, A. Schad, P., Jahn, R., Amelung, W., Bannert, A., Cao, Z. H., Fiedler, S., Kalbitz, K., Lehndorff, E., Mueller-Niggemann, C., Schloter, M., Schwark, L., Vogelsang, V., Wissing, L., Koegel-Knabner, I.
  
• 2014. Organic carbon accumulation on soil mineral surfaces in paddy soils derived from tidal wetlands. Geoderma 228–229, 90–103
  Wissing, L., Kölbl, A., Schad, P., Bräuer, T., Cao, Z.H., Kögel-Knabner, I.
  
• 2015. Spatial distribution of soil organic matter in two fields on tidal flat sediments (Zhejiang Province, China) differing in duration of paddy management. Journal of Plant Nutrition and Soil Science, 178: 649-657
  Kölbl, A., Mueller-Niggemann, C., Schwark, L., Cao, Z.H., Kögel-Knabner, I.
  
• 2016. Response of Vertisols, Andosols, and Alisols to paddy management. Geoderma, 261: 23–25
  Winkler P., Kaiser K., Kölbl A., Kühn T., Schad P., Urbanski L., Fiedler S., Lehndorff E., Kalbitz K., Utami S.R., Cao Z., Zhang G., Jahn R., Kögel-Knabner I.