The Historic Russian Soil Collection

Two of the critical questions for terrestrial carbon budgets are how soil carbon stocks have changed over the past century and what proportion of soil organic matter cycles fast enough to respond to environmental perturbations. In the Historic Russian Soil Collection Project Andrei Lapenis (http://www.albany.edu/faculty/alapenis) and I are are characterizing soil carbon dynamics in a pristine Russian steppe (http://www.albany.edu/faculty/alapenis/research/sites/htm) using 100-year-old soil archives and modern samples collected from the same site in 1997.

The radiocarbon content of the archived and modern samples allowed us to derive narrow estimates of the amount of decadal-cycling SOM, and generate rougher estimates of the turnover time of that pool. In the pristine stepp, the total amount of organic carbon did not change appreciably between the 1903 and 1997 sampling dates. The carbon stock in the top 20 cm and 1 m varied by less than 6% between the two pristine modern sites or between the modern soil and the archive. The soils contain about 32 kg C/m², with one-third of that in the top 20 cm and two-thirds below that level. The surface horizons were dominated (77-90%) by slow SOM with 23-40 y turnover times. At 20-40 cm depth, approximately 50% of SOM was slow cycling, with turnover time of 40-100 y.

In 1998, we identified and sampled soils adjacent to the pristine site from a field that has been under a long-term tillage regime (http:\\www.albany.edu/faculty/alapenis/research/sites/htm)

We are currently processing these soils to compare the carbon stock and turnover time with between the tilled and protected soils.

This work was supported by a grant from NSF.

For more information on this project, please contact:

Margaret Torn
Geochemistry Department
Earth Sciences Division
ph: 510-495-2223
email:mstorn@lbl.gov