Word used in English, though actually French, for "the art of mixing lab science with field work"

Solution 1:

Are you thinking of bricolage?

Bricolage

In the practical arts and the fine arts, bricolage (French for "tinkering") is the construction or creation of a work from a diverse range of things that happen to be available, or a work created by such a process.

The term bricolage has also been used in many other fields, including critical theory, education, computer software, and business.