The overall objective of this project is to characterize the molecular relationship between cover crop species diversity, the composition and function of the soil microbiome, and agricultural soil health. We hypothesize that: (1) there is significant variation in exudate composition between different cover crop species relevant to US agriculture; (2) species specific plant exudate effects will lead to variation in microbial community function; and (3) these changes in the soil microbiome directly and indirectly influence soil health. These hypotheses will be tested using a combination of laboratory and field experiments as outlined in the following objectives:Objective 1. The root exudate profiles from model cover crop species will be characterized in tractable hydroponic and greenhouse systems.Objective 2. The membership, metabolic capabilities, and function of microbial communities responding to root exudates will be deciphered in laboratory microcosms.Objective 3. The direct and legacy effect of cover crop species on soil health and microbial membership will be quantified in an agricultural field.