In this scene, you seem to have some pretty drastic scaling issues. Think about the size of the tree vs. the size of the mountain. Your tree is literally as tall as a snow-capped mountain right now. This is a huge issue that you either need to make deliberate, or fix.
As for the grass:
This is a combination of multiple issues. The first is of scale. If this were a real mountain, those grass blades would probably be somewhere around the size of a tree, or at least a large shrub (upper image).
A second vital issue is density. You have nowhere near enough grass blades, or otherwise nowhere near full enough coverage. Grass density also varies depending on location, so make sure to paint those Density maps!
A third issue is that when you used Path, you chose to make them cones. Grass is nowhere near a cone shape. If anything, Ribbon would work better for grass, but Objects of modelled grass blades / clumps are ideal.
Lastly, all of your grass appears to be a plain diffuse shader with no color variation. Real grass is glossy, translucent, and has plenty of color variation on multiple scales depending on the amount of sunlight, amount of water, and even just kind of random factors. I would actually recommend using at least 2 particle systems for grass: one for living grass, one for dried out grass, and each one has a separate density map.
To make it look like grass from that far away, a solid but somewhat bumpy surface with textured detail would likely work more effectively than grass particles. I would instead transition the grass particle field into a Tree or Bush particle field, and concentrate a bit more on the materials.