An inventory of carbon stocks under native vegetation and farm fields in south-central Montana

Abstract

Annually, carbon dioxide (CO 2) is emitted from the burning of fossil fuels, creating a CO 2 emission source. Vegetation and soils capture and store these emissions, however not nearly in the quantity being emitted. Disparity between sources and sinks of CO 2 emissions requires actions focused on reducing CO 2 emissions (CCSP, 2007). Cabin Creek Ranch, near Shepherd, MT offers a rich opportunity to understand the current carbon balance within various land cover types, and to determine the effect that cropping, grazing and concentrated feeding has on the potential for ranch soils to sequester additional carbon. Samples were collected from 30 soil and 16 vegetation locations, which were randomly chosen in a variety of cover types. Soil samples were taken every 15 cm throughout the soil profile (down to 100 cm, if possible). Four .25 m 2 frames were used to collect herbaceous material 25 meters in each cardinal direction from soil pit center. Clay and land cover type were found to have a significant interaction on the organic carbon content in the soils (p=0.021). Additionally, dryland crop was found to be significantly different in organic carbon content compared to other cover types (p<0.0001). Therefore, management towards a specific land cover type could help mitigate CO 2 emissions. For example, revegetating dryland crop fields to a native grassland, sagebrush or forest, the landscape would be able to store 230%, 232% and 256% more organic carbon, respectively. Understanding the carbon balance on the landscape scale contributes to understanding the global carbon balance to help mitigate burning of fossil fuels.