Modelling Soil Organic Matter Dynamics – Global Challenges - Sustainable Management of Soil Organic Matter - page 35

K.Paustian ModellingSOMDynamics

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Modelling Soil Organic Matter
Dynamics - Global Challenges

K. P AUSTIAN

Natural Resource Ecology Laboratory, Colorado State University,
Ft Collins, CO 80523, USA

Introduction

Soil organic matter (SOM) modelling is gaining recognition as a key part of
efforts better to understand, and manage, the terrestrial carbon cycle. The
influence of the terrestrial carbon cycle on greenhouse gas emissions and
uptake, and the potential feedbacks on long-term climatic change, have
become front page news. Major questions with far-reaching societal
impacts include: what is the current role of soils as a source/sink for
increased atmospheric CO 2 ?; will climate change increase CO 2 emissions
from soil, resulting in a positive feedback to drive global warming?; and can
soils be managed effectively to mitigate increased greenhouse gas loading?
Answers to these questions require the application of models to quantify
and predict SOM dynamics as a function of environmental factors and
human management. Consequently, SOM modelling has played a promi-
nent role in much of the recent research on climate change and the global
carbon cycle (e.g. King et al ., 1997; Field and Fung, 1999; Schimel et al .,
2000).
The requirements for an accurate accounting of greenhouse gas
emissions and sinks is central to the UN Framework Convention on
Climate Change (FCCC) which requires national reporting of all major
sources and sinks, including soils. Modelling will play a key role in
integrating the variability and dynamics of soils, climate, topography and
land use (as they affect SOM) to provide national estimates of soil C stock
changes (e.g. Eve et al ., 2000; Tate et al ., 2000). SOM models have been
used to estimate the potential for soils to sequester carbon and thus mitigate