I need mountains on land, but how? I already have one displace (bottom of the sea). Some advice, please?
Sorry for maybe stupid question. I am beginner and Czech, this is deadly combination.
If I get your question right, since displacement can have many levels...(positive and negative, it depend on the "midlevel" you choose), you could displace with an image that could displace both sea depth and land height (mountains): in the image below, with midlevel 0.5, white is above Z=0, black is below Z=0, gray is in the middle (to get Z=0 you need a perfect middle grey, so RGB(0.5,0.5,0.5))
Can this concept work in your setup?
Since you unaccepted this answer, I guess it doesn't help you really. It's ok.
To the benefit of other readers, too, looking for similar results, I'll add a more "realistic" example with a plane (I know a globe is not as simple, but a plane is simpler to understand), though, to better visualize how it can be done: it is just matter to have at least a very good gradient.
Let's build an "Island"...
I took a height map from http://www.reallusion.com/iclone/Help/EarthSculptor/Image/Utilizing_Height_Map_05.jpg
then you could also paint over the UV texture to "adapt" it to your land/seascape