Carbon Fluxes From Continuous Cotton and Pasture for Grazing in the Texas High Plains.

A carbon sequestration study was initiated in the Texas High Plains in 2010 to understand the magnitudes of carbon pools and fluxes for selected agro-ecosystems. As part of this study, carbon dioxide flux measurements were made from two irrigated commercial fields using eddy covariance methods and automated soil respiration chambers.  These fields include a center-pivot irrigated pasture of WW-B. Dahl grass for grazing and seed and a subsurface drip irrigated cotton field.  The carbon fluxes were used to calculate the net ecosystem exchange (NEE) and net primary production (NPP) from these two contrasting fields in the study. In addition to carbon flux measurements, other continuous measurements were made including latent heat flux, sensible heat flux, soil heat flux, net radiation, and fraction of absorbed photosynthetically active radiation (fAPAR), along with periodic measurements of leaf area index, vegetation cover, and biomass. In this presentation, we are presenting the preliminary results from this study.