Eddy covariance is a method for large scale monitoring of greenhouse gas emissions. Using the eddy covariance technique, we can continuously measure carbon dioxide and water exchange at the ecosystem scale at a cropland compost amendment site in Concord, CA. This technique integrates greenhouse gas exchange and evapotranspiration across ~300 square meters, which facilitates up-scaling and modeling activities. Ecosystem-scale measurements of evapotranspiration will also allow an unprecedented examination of how compost (and other) amendments influence water budgets.