The soil is seeped with Akroydiesel, the sloshing remains of a mass of animal and plant matter rendered liquid hundreds of years ago by a terrible biological attack that nearly ended humanity. The substance can be broken into two parts, Akroy and Diesel. Akroy excites biological growth, which can be used in the fields to stir growth in even the most desolate of lands when properly treated. Diesel is an incredibly versatile and powerful liquid fuel for combustion engines.
Together these substances have made reclamation of the world by humanity possible in only a few centuries--despite serious changes to the atmosphere, which hamper all radio signals, and led to the invention of new technologies for long ranged communication. Technical understanding of most digital computation has been lost, though many of the same principles are deployed crudely in analogue format.