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| Titel |
Assessment of management systems according to their impact on SOM turnover on regional scale |
| VerfasserIn |
Uwe Franko, Ralf Gründling, Felix Witing |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250124084
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| Publikation (Nr.) |
 EGU/EGU2016-3458.pdf |
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| Zusammenfassung |
| Models are widely used to predict SOM dynamics as reaction on management and
climate. But the predicted SOM dynamics depend also on the initial conditions that on
field scale are much better available from direct measurements than on regional
scale.
In the case of the models CANDY and CCB that are both build upon the same turnover
equations it is possible to predict the steady state amount of SOM from the carbon
reproduction flux (Crep) –the amount of carbon from fresh organic matter that is incorporated
into SOM – and from the average turnover conditions that are expressed as Biologic
Active Time (BAT). Both variables are combined to a new indicator, the reproduction
index:
REP_IX= Crep / BAT
The required data base comprises climate data (air temperature and rainfall), topsoil
texture (clay and fine silt) as well as crop yield and amount of organic amendments. An
implicit information base comes from the model parameters that describe the relation
between yield and amount of crop residues and root material as well as the quality of the
different sources of fresh organic matter.
According to the models the time course of SOM for a given management system is
completely defined by the initial SOM content and the REP_IX. Any change in climate or
management leading to a different REP_IX can be compensated by appropriate measures that
will restore the previous value of REP_IX.
This concept was applied for two regions in Austria (Mühlviertel and Marchfeld) and for
the federal state Saxony in Germany in order to identify possible changes in carbon cycling
and to identify adaptation messages.
Depending on the individual situation it may be sufficient to have an increase
in crop yields to stabilize SOM storage against climate change – as it has been
shown in some long term experiments. In other cases it may be recommended to
introduce additional intercrops to increase the Crep flux or to increase areas with
conservation tillage to decrease BAT. Those measures may also be required if carbon is
withdrawn from the reproduction process for instance due to the production of biogas. |
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