Carbon capture of irrigated Australian broad-acre crops

With respect to the mass and energy balance, there has been an extensive amount of research done to investigate the carbon sequestration potential of various terrestrial ecosystems world-­‐wide; however, very little has been done to quantify water, carbon and energy fluxes of irrigated broad-­‐ acre crops across spatio-­‐temporal scales for common Australian conditions and soil types. This study focuses on the use of eddy covariance methodologies to determine the empirical relationship between these fluxes for three of the major crops grown in a gravity-­‐fed irrigation system in Australia; maize, rice and wheat. Here we present the uptake or release of carbon dioxide in relation to water use (evapotranspiration) at different phenological stages of the crop at the field scale; and the extrapolation of these to provide an estimate of fluxes at the regional scale based on similar soil types. The results of this study will be used to upscale eddy covariance measurements through the application of a biophysical diagnostic model in order to bridge the gap between ground-­‐based observations and satellite-­‐derived information. This will ultimately provide a useful tool to estimate water, carbon and energy fluxes at different spatio-­‐temporal scales and assist in the closing of regional and global water and carbon budgets.