Chris,
Assuming you captured raw you can wind the exposure slider right down 2-3 stops and get the natural dark foreground you want, export it as a 16 bit PSD or tiff.
Then do one as you have presented it here and export it as a 16 bit tiff
Then blend the darker foreground with the brighter sky in Photoshop, GIMP etc.
You can also do it in Lightroom albeit in a less sophisticated way.
Joe
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