Here is a great read on the impact of measuring and managing C02 with a focus on measuring soil biology and not just mineral nutrients. Adding a biological component to soil testing will be key in understanding C02 and crop nutrient supply. Did you know that plants demand more C02 than they do nitrogen? Did you know that our soils provide a direct supply of C02 to growing crops? Making sure we have optimum C02 levels is key key to driving yield higher. 

Article: http://beyondagronomy.com//cmsFiles/documents/document55c4ef1e10b8d.pdf