Surface-Atmosphere Carbon Fluxes On a Southern High Plains Shortgrass Prairie.

The Southern Shortgrass Prairie Ecoregion is found on 27 million ha in mostly west Texas and eastern New Mexico.  Half the landcover of this ecoregion is composed of grasslands dominated by blue grama and buffalograss. The region is characterized by low and erratic precipitation, extreme temperatures and relatively low net primary productivity compared with other grasslands. Soils generally develop a shallow horizon with increased carbon, indicating that some carbon sequestration occurred. Upland soils on which shortgrass prairie occurs are also recognized as weak sinks for atmospheric methane. Given its areal extent, shortgrass prairie could have potential to sequester atmospheric carbon. We established a site on an extensive shortgrass prairie pasture in the western Texas Panhandle to measure carbon dioxide and methane fluxes using the eddy covariance method. Our objective was to determine whether the pasture was a net sink or source for atmospheric carbon. Additionally, we were able to collect data during the latter half of the historic Texas drought of 2011. Time series of carbon dioxide and methane fluxes are presented and net carbon fluxes calculated.