Comparison of Carbon, Water and Energy Fluxes Between Grassland and Agricultural Ecosystems.

A study was initiated in the Texas High Plains to understand the magnitudes of water, energy and carbon fluxes for selected agro-ecosystems. As part of this study, carbon dioxide and energy flux measurements were made from agricultural 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 several agricultural fields.  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.