Quoting from the abstract of the paper which apparently introduced meadows:
> We study a new axiomatic concept for number systems with division that uses only equations: a meadow is a commutative ring with a total inverse operator satisfying two equations which imply that the inverse of zero is zero. All fields and products of fields can be viewed as meadows.
In other words, since $\mathbb{R}$ is a field you just need to extend it with $0^{-1} = 0$.