International workshop on

Koli (c) Metla/Erkki Oksanen

Development of Models and Forest Soil Surveys for Monitoring of Soil Carbon

April 5-8, 2006 at Koli, Finland

Monitoring Soil C Stocks Using a Simulation Model-Based Approach

Stephen M. Ogle

Natural Resources Ecology Laboratory, Colorado State University, Fort Collins, Colorado, 80523, USA

Modelling offers opportunities for monitoring soil C stocks across large regions, but it also presents unique challenges it order to produce a viable approach with reasonable accuracy. There are several steps for developing a robust model-based monitoring system, including 1) select/develop an appropriate model, 2) verify the adequacy of the model by comparing to measurement data, 3) identify sources of model input data such as soil surveys, land use and management activity records, and climatic data, 4) assess uncertainties, 5) implement the model, and 6) evaluate results with an independent set of measurements.

This approach has been used to develop a model-based monitoring system for US agricultural lands. The system has several components, including 1) a simulation model (i.e., Century Model) for estimating changes in soil organic C storage, 2) spatio-temporal model input data on management activity and environmental conditions, 3) a Monte Carlo Analysis for addressing uncertainties in model input data, 4) an empirically-based estimator for incorporating additional uncertainties associated with the structure of the simulation model, and 5) a data management system to organize and process model inputs, simulations and results. Underlying this assessment are national soil survey data, which provide key soil characteristics needed as model input; climatic data based on a model-based interpolation of national weather service records; and National Resources Inventory data that are used to schedule land use and management activity based on historical patterns recorded at about 400,000 point locations.

This system has been used to estimate a net sequestration in US agricultural lands during the 1990s, ranging from 21 to 25 Tg C yr -1. With a well-developed monitoring system, trends in soil C stock changes can be used for policy assessment, including an evaluation of GHG mitigation, as well as for reporting purposes as required for domestic programs and international treaties (e.g., UNFCCC).

   Päivitetty:   02.03.2006 / EKel Metla : Events   Palaute Metlan etusivulle
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