Wednesday, November 15, 2006 - 8:30 AM

Estimating Gross Primary Production of Tallgrass Prairie at Watershed Scales Using Eddy Covariance, Flux Chambers, and Temporal Stability Theory.

Jay Ham1, Patrick Coyne2, Clenton Owensby1, Kira Arnold1, Lisa Auen1, and John Murphy1. (1) Kansas State Univ, Dept of Agronomy, Manhattan, KS 66506, (2) KSU Ag. Research Cntr.-Hays, 1232 240th Ave., Hays, KS 67601-9228

Gross primary production (GPP) of tallgrass prairie near Manhattan, Kansas was calculated from eddy covariance measurements of net ecosystem CO2 exchange (NEE) and automated chamber‑based estimates of total ecosystem respiration (Rt). To determine spatial variation in carbon fluxes, soil respiration and hyperspectral reflectance were measured on transects that bisected the footprint of the flux tower as well as all other landforms in the catchment of a watershed. A simple modeling approach based on temporal stability and landform position was used to estimate mean GPP, NEE, and Rt at the watershed scale.