2012 Annual Report 1a.Objectives (from AD-416): Evaluate the impact of various cropping and tillage systems on the flux of greenhouse gases to the atmosphere. 1b.Approach (from AD-416): Texas A&M University will purchase a Shimadzu Gas Chromatograph System for use at the NSDL. NSDL, ARS will run gas samples that will be used in cooperative publications and will use the instrument as needed for other research projects. 3.Progress Report: The Shimadzu Gas Chromatograph System has been purchased and is being used for the analysis of gas samples for evaluating the impact of various cropping and tillage systems on the flux of greenhouse gases to the atmosphere.