Dr Andreas Möller¹

¹Federal Institute For Geosciences And Natural Resources, Hannover, Germany

In the past decades the common hypotheses for long-term soil organic matter dynamics was based on controlling factors like biomass source, sorption and desorption processes, climate, land use and soil texture. New research, however, revealed that this hypothesis may have to be adapted and other factors may be more relevant. The major problem is that most factors controlling long-term organic carbon dynamics are connected to each other. Thus, the selection of causal model parameters is essential to eliminate translucent causalities. It is already common understanding that biomass source and carbon pools are not relevant in the long-term. All physically reachable carbon gets microbial degraded over time, even charcoal. Hence, which are the parameters truly triggering the differentiation of organic carbon stocks in soil? A statistical evaluation of Germany wide topsoil data, including data from the state geological surveys of Germany, showed that soil moisture conditions may be the key factor controlling soil organic carbon content apart from soil genesis and land use. Additionally, the age of the soil may also be relevant. Comparing soils of the younger Weichsel with the older Saale glacial era in the lowlands of northeast Germany showed significant differences over different soil moisture regimes. However, less the age of the soil may cause the difference, but more the mineral composition of the soils, similar to the effect known from podsols. Even after hundreds of years of intensive agriculture sandy podsols reveal significantly higher carbon content in the plowed layer than most other soils. On the other hand, factors like temperature and soil texture seem to be less important. The results show that the common hypothesis of long-term organic carbon dynamics in temperate soils may have to be review.

Biography:

Since 03.2001                 Research associate at the Federal Institute for Geosciences and Natural Resources in the unit “Soil Protection, Soil Analysis”; Focus on soil organic matter, carbon stocks, biochar, and technical cooperation

02.2012 – 01.2015         Secondment to the State Office for Mining, Energy and Geology in the department “Agriculture, Soil Protection and Regional Planning”

05.2005 – 08.2017         Lecturer at the University of Hannover; Fundamentals of the WRB

11.1997 – 04.2001          PhD at the Department of Soil Science and Geography, University of Bayreuth; Thesis: Dynamics of organic matter in the mountain forest ecosystem of N-Thailand

10.1994 – 05.1997          Geography at the University of Erlangen