The basic idea is, every asset, every material on that asset, is a separate draw call, pretty much anything that needs to be rendered in is a draw call. Now with landscapes it is a bit different, however I’d look into the details when you create the landscape, these one specifically
I’d take a bit of time to test out different values and see what gives the best result.
Depending on the final build you are aiming for there are differences in budget. However, if I remember right, its ok if you have around 5-7mil triangles per scene, and around 3k draw calls. That being said this is not set in stone, and refers to ue4, and last gen consoles mainly.