Organic Carbon Content in Surface and Subsurface Soil on a Toposequence on the Peterson Ranch in Poly Canyon, San Luis Obispo

Soil organic carbon (SOC) is directly related to soil organic matter (SOM), and is important in the functionality and stability of terrestrial ecosystems. Soil organic carbon is also an important pool for C storage and small changes of SOC may cause significant gains and losses in the large scale carbon cycle. The mechanisms by which SOC is transported and stored however are not widely studied. This study was conducted to determine if there is a relationship between toposequence and SOC in a small watershed on the Peterson Ranch, San Luis Obispo, CA. Nine soil pits were dug on various hillslope positions. The soils were described, and samples were taken from the surface and subsurface based on the soil descriptions. The sampled were run in a C and N analyzer for the C and N content and C/N ratio. The SOC increased from bottom to top of the sampling sites in contrast to previous research. A relationship between toposequence and SOC does not seem to exist in this watershed. The SOC is more related to the clay content. The N followed a very similar trend to that of the SOC. Animal burrowing has contributed to the subsurface SOC