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
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Model stratified sampling for soil carbon stock changes

Mikko Peltoniemi

Finnish Forest Research Institute (Metla), e-mail: Mikko.Peltoniemi@metla.fi

Monitoring of carbon stocks in soil and organic matter has become an important issue due to reporting requirements set by Climate Convention and Kyoto Protocol. Repeated measurements provide a direct way to assess possible changes in soil carbon stocks.

Forest soils are often highly heterogeneous and most of this heterogeneity is already present within small distances. This presents a practical problem for measuring soil carbon content, since a large number of samples are required to get a reliable estimate of mean stock. Detection of changes in soil carbon stocks is even more difficult, since the expected changes are usually extremely small in comparison to stocks of carbon. In addition to these challenges, field work needs to be efficient and practical, which sets further restrictions on soil sampling.

In this work, we used predicted changes of soil carbon stocks as a basis for stratification of soil sampling. We simulated soil carbon contents for permanent sample plots of national forest inventory. The sites that accumulated or lost most carbon during the measurement interval had a higher probability to be sampled. Also the assumed homogeneity of soil carbon changes within a plot affected the probability of the plot to be sampled. The specific question of the study was: How much the model based stratification of soil sampling could decrease the sampling effort to detect a significant change in soil carbon.

 
   Päivitetty:   02.03.2006 / EKel Metla : Events   Palaute Metlan etusivulle
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