Having read that still don't know what the project really is. A venue for people and corporates to discuss open agtech and a source of funding for open agtech software?
"The AgStack Foundation will not engage in building software applications but will instead focus on the software infrastructure (tools, frameworks, and models) that will be needed to build, manage and run applications by the members and users"
My basic understanding is that on one side you have companies who want to sponsor open source tech they depend on, and on the other side you have open source developement teams who would like to be supported; the Foundation facilitates interaction between these 2 sides.