[Chris2048]

Hmm, is brine a waste product of desalination? Interesting.

Can brine be duped on regular and/or sandy land and make it more fertile via minerals, or will briny/salty land be less fetile?

[Xylakant]

Salty land will become less fertile to the point of becoming a desert. Very few plants actually like salty soil (mostly marsh plants). "Salt the earth" is an expression for that reason.

[saagarjha]

Yes, and it's usually exceptionally bad for any environment.