ORGANIC-CARBON AND NITROGEN STOCKS AND STORAGE PROFILES IN COOL, HUMID SOILS OF EASTERN CANADA

Current interest in carbon (C) exchange processes between terrestrial ecosystems and the atmosphere have identified a need to assess soil C stocks or inventories for specific soil types and climates. In this st udy, the mean store of C and nitrogen (N) was determined in the soil p rofile of several Gleysolic, Podzolic, Luvisolic, and Brunisolic soils under different agricultural management systems, in the cool, humid r egion of eastern Canada. Based on a total of 69 management treatments from 16 agroecosystem sites, mean soil C and N densities (to a soil de pth of 60 cm) ranged from 3.1 to 13.1 kg C m(-2) and from 0.36 to 1.05 kg N m(-2). The C:N ratio ranged from 8.3 to 17.1. Distribution of C and N down the soil profile showed a relatively regular pattern of C a nd N decrease with depth. Estimated C stocks or storage for the 1-m so il depth ranged from 8.3 to 13.3 kg C m(-2) for the Gleysolic soils, a nd 5.4 to 10.5 kg C m(-2) for the Podzolic soils, with an overall rang e and mean for all soils of 3 to 16 kg C m(-2) and 9.8 kg C m(-2) +/- 2.8. This indicates that some agricultural soils in eastern Canada pos sess a relatively high potential for organic matter storage.